QBanks

Question 1

How would salicylate toxicity affect pH of a patient?

Answer 1

Mixed anion-gap metabolic acidosis (late) & respiratory alkalosis (early): pH usually normal.

• May be accompanied by N/V, confusion, dizziness, tinnitus, fever, and tachypnea.
• Tx: sodium bicarbonate.

Question 2

A patient on antihypertensive medication presents with acute-onset respiratory difficulty along with severe circumoral, periorbtial, and facial edema without pruritus and skin rashes. What are ADRs?

Answer 2

ACEI:

• Angioedema (due to increased bradykinin)
• Hyperkalemiae.
• Renal insufficiency (prevents the efferent arteriole from constricting, thus decreasing the glomerula pressure and GFR).
• Can cause first-dose hypotension in patients with volume depletion (diuretic use).

The risk of cough & angioedema is much lower with ARBs (eg. valsartan, losartan).

Question 3

What’s the most common kidney stones? What precipitates it?

Answer 3

Calcium oxalate crystals: radiopaque, dumbbell shaped stones.

• Ethylene glycol (antifreeze) ingestion.
• Vitamin C abuse.
• Hypocitraturia: Has stone-preventing effects; associated with ↓pH.
• Low dietary calcium: Dietary calcium is ingested with oxalate in food and forms insouble calcium oxalate salts in the intestinal lumen, resulting in decreased gut absorption and therefore reduced renal excretion of oxalate.
• Diet high in oxalates & Malabsorption (e.g., Crohn disease)
  
  • Increased intraluminal fat, which will readily bind calcium –> Decrease in the calcium –> Less calcium is available to bind and trap oxalate in the gut.

Question 4

A 5-year old girl presents with conjunctivitis, rash on hands & feet, cervical lymphadenopathy, strawberry tongue, and high fever. Dx & complication?

Answer 4

KAWASAKI

• Complications: Coronary artery aneurysms.
• Tx: Aspirin (avoid Aspirin in children with viral infection due to Reye syndrome, except for Kawasaki disease).

Question 5

A 12-year-old girl with PMH of pharyngitis now presents with delayed rumbling mid-to-late diastolic murmur. Dx?

Answer 5

Mitral stenosis, which is often a late complication of rheumatic fever.

• In isolated MS, cardiac and pulmonary pressures proximal to the stenotic mitral valve are markedly elevated.
• However, diastolic pressure in teh left ventricle (LV) is usually near normal or even decreased with severe stenosis.
• Increased LV diastolic pressure in a patient with suspected MS suggests that the aortic valve is also dysfunctional.

Question 6

• Myxomatous changes in the media of large arteries.
• Fragmentation of elastic tissue and separation of the elastic and fibromuscular components of thet unica media by small, cleft-like spaces that become filled with amorphous ECM.
  *

Answer 6

Cystic medial degeneration

• Seen in Marfan syndrome (mutation of the fibrillin-1 gene).
• Aortic aneurysms & dissection.
• MVP.

Question 7

Which lipid-lowering agent can increase HDL but has not shown to be effective in reducing mortality rate? What are possible ADRs?

Answer 7

Niacin(B3):

• MOA: Inhibits lipolysis (HSL) in adipose tissue.
• Increases HDL.
• Also used to treat Pellagra, caused by niacian deficiency.
• Red, flushed face (due to prostaglandins); hyperglycemia; hyperuricemia (gout).

Question 8

A 10-year old boy is brought to the ER by his mother due to several days of bloody diarrhea, irritability, fatigue, and pallor. The mother mentions that they took a family trip to Mexico where her son ate a lot of food from the local street vendors.

Answer 8

EHEC:

• Shiga-like toxins that are capable of inhibiting protein synthesis (preventing tRNA binding to the 60s ribosomal subunit and inhibitng protein synthesis).
• Closely related to Shigella dysenteriae
• Unlike other species, does not ferment sorbitol during overnight incubation.
• AB toxin (active A subunit and 5 binding B subunits): plasmid coding for it is transmitted by a temperate bacteriophage.
• HUS: thrombocytopeniae, microangiopathic hemolytic anemiae, renal insufficiency (Creatinine)

Question 9

Acid in the blood of a newborn was identified to be a leucine. Presentation and Dx?

Answer 9

1. Maple-syrup urine disease
   * Defect in branched-chain a-keto acid dehydrogenase, leading to increased leucine/isoleucine/valine.
2. a-keto acid dehydrogenase (in addition to pyruvate dehydrogenase and a-ketoglutata dehydrogenase) requires 5 cofactors:

• Thiamine
• Lipoate
• CoA
• FAD
• NAD

3. Some patients with MSUD improves with high-dose thiamien Tx.

Question 10

What’s the physiologic principle underlying BB in a patient with CAD?

Answer 10

1. Slow AV nodal conduction, prolonging the PR interval; do not have specific ffects on QRs or QT interval durations.
2. Decreases renin secretion.

Question 11

A 32-year-old male patient from Peru presents with secondary achalasia (destruction of myenteric plexi in the esophagus), megacolon, and megaureter. Dx & transmission?

Answer 11

Chagas disease; Trypanosoma cruzi transmitted by Triatoma (reduviid) bugs.

• Nifurtimox

Question 12

Oligohydramnios seen in Potter syndrome is caused by a failure of?

Answer 12

Development of the ureteric buds (metanephric diverticulum)*

• Derived from caudal end of mesonephric duct; gives rise to collecting tubules/ducts, major/minor calyces, renal pelvis, and the ureters.
• Interacts with metanephric mesoderm to induce differentation of glomerulus through to DCT.

Also can be secondary to ARPKD.

Question 13

What pharmacologic Tx can reduce the mortality in patients with diabetic nephropathy ?

Answer 13

ACEI (inhibits Gq pathway) or ARB (e.g., losartan) - act by dilating the efferent arteriole, which help to decrease the intraglomerular pressure and prevent further progression of albuminuria.

Question 14

What medication can be given to a hypertensive patient with BPH? And BPH only?

Answer 14

Doxazosin (alpha-1 antagonist); tamsulosin

Question 15

Abrupt-onset gross hematuria in an otherwise healthy, young patient ?

Answer 15

Renal papillary necrosis:

• Sickle cell disease or trait
• Analgesics
• Acute pyelonephritis
• Diabetes

Question 16

What medication is the 1st line of choice for patient presenting with high TG? What ADRs can you expect?

Answer 16

Fenofibrates (e.g., gemfibrozil)

1. MOA:

• Upregulate LPL –> ↑ TG clearance & decreased VLDL production.
• Activates PPAR-a to induce HDL synthesis.

2. ADR:

• Myopathy (especially in conjunction w/ statins)
• Cholesterol gallstones (inhibition of 7a-hydroxylase, reduces the converstion of cholesterol to bile acids. ).

Question 17

Which of the following would be an effect of nadolol/propranolol/timolol but not of atenolol/esmolol/metoprolol?

Answer 17

Vasoconstriction of pulmonary, skeletal muscle (B₂)

• Safe to use in asthmatic patients & COPD patients.

B1 adrenergic receptors are found in cardiac tissue and on renal juxtaglomerular cells, but not in vascular smooth muscle.

Question 18

A 4-year-old child presents with grade II/VI holosystolic murmur at left sternal border. Dx?

Answer 18

VSD, the most common murmur.

Question 19

• Leucine Zipper.
• Helix-loop-helix
• Zinc Finger.
• DNA binding basic region is primarily composed of basic amino acids (eg, arginine, lysine), which allow it to bind in the major groove of (-) DNA.

Question 20

A 24-year-old woman complains of increased frequency of urination & burning sensation when she urinates. Denies fever, chills, flank pain. Urinalysis is positive for leukocyte estrase, nitrites, bacteria, and WBC casts. What’s the most common organism & Tx?

Answer 20

Still an E.Coli : A gram (-) rod that ferments lactose, forming pink colonies on McConkey agar.

• Remainder: S. saprophyticus; Proteus; Klebsiella; Enterococci.
• Tx: 3 days course of fluoroquinolone or TMP-SMX.

Cystitis can progress to become acute pyelonephritis in setting of vesicoureteral reflux (similar U/A+ flank pain/CVA tenderness/fever/chills/hematuria with casts).

Question 21

Celecoxib: COX-2 inhibitor

Answer 21

• For patient with PUD or GI distress: celecoxib have no effect on COX-1, minimizing gastroduodenal toxicity.
• Usage of COX-2 inhibitors (celecoxib) selectively decrease PGI2, leaving the action of TxA2 unopposed. This could well result in increased CV event due to the tonic, prothrombtic action.
  
  • Does not impair platelet aggregation.s
• Inducible enzyme that’s undetectable in most tissues under normal conditions.

Question 22

Fever, erythema around the foley urine catheters/IV/prosthetic devices/peritoneal dialysis is most likely caused by?

Answer 22

• S. Epidermidis*
• Migrates along the tubing from the skin to the inside of the body with the help of biofilm creation.

Answer 23

Aminoglycoside

• Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin
• Irreversible inhibition of initiation complex through binding of the 30S subunit; can also cause misreading of mRNA.
• Synergistic w/ B-lactam antibiotics (eg, penicillins & vancomycin): allows aminoglycosides to penetrate the gram (+) bacterial cells.
• Ototoxicity, nephrociticy, teratogen.
• Resistance: group transferases that covalently modify the antibiotics (acetylation/phosphorylation/adenylation).

Question 24

A patient presents with pheochromocytoma. What agent will antagonize both the vascular and cardiac actions of hormones released from pheochromocytoma?

Answer 24

In pheochromocytoma, norepinphrine is released that exerts its agonist effect on α1, α2, β1 receptors:

• Labetalol is a nonselective antagonist at α- and β-receptors
• Irreversible α antagonist: phenoxybenzamie.

Question 25

TRH upregulates prolactin secretion (in setting of primary hypothyroidism).

Question 26

• Tearing, sudden-onset chest pain radiating to the back
• PMH of severe HTN (eg, 180/120 mm Hg).
• Markedly unequal BP in arms.
• EKG does not show any acute ST segment or T wave changes.

Answer 26

Aortic dissection

• Stanford type A: ascending aorta
• Stanford type B: descending aorta; originate close to the origin of the left subclavian artery.
• Risk factors: HTN, bicuspid aortic valve, inherited connective tissue disorder (eg, marfan syndrome).

Question 27

Given a history of cocaine abuse in a patient with chest pain, which medication should be avoided?

Answer 27

Cocaine blocks presynpatic reuptake of NE and increases release of catecholamines form the adrenal gland:

• B-blockers because of the resulting unopposed alpha-effects, leading to vascular smooth muscle contraction.

Question 28

Autopsy of elderly person will reveal deposits of this substance in heart, colon, liver, kidney, eye, and other organs.

Answer 28

Lipofuscin, a yellow-brown “wear and tear” pigment (cytoplasmic granules) associated with normal aging.

Question 29

A patient presents with constitutional symptoms, arthralgias, pleuritic chest pain, and anti-histone antibodies. DDx?

Answer 29

Procainamide, hydralazine, and isoniazid are metabolized via phase II acetylation in the liver.

Question 30

The autopsy finding of sterile platelet-rich thrombi attached to the mitral valve leaflets is characteristic of?

Answer 30

Nonbacterial thrombotic endocarditis (NBTE) (marantic endocarditis).

• Advanced malignancy
• Chronic inflammaotry disorders: antiphospholipid syndrome, SLE
• DIC in patients with sepsis.
  *

Question 31

An older woman presents with new-onset headaches and jaw pain. Accompanying symptoms include fever, weight loss, scalp tenderness, and vision loss. The ESR is elevated. Dx & Tx?

Answer 31

Giant cell (Temporal) arteritis:

• Associated with polymyalgia rheumatica: ↑ ESR, CRP, normal CK.
• Temporal artery biopsy: intimal thickening, elastic lamina fragmentation, multinucleated giant cells.
• Complications: ischemic optic neuropathy.
• Tx: glucocorticoids.

Question 32

A pregnant woman in her 3rd trimester presents with 120/70 mm Hg while sitting upright and 90/50 mm HG while lying supine. Dx & Tx ?

Answer 32

IVC compression; the large uterus compresses the IVC, decreasing venous return to the heart;

Question 33

A patient is given a medication that has a very little risk of inducing torsades de points unlike other drugs that cause QT prolongation. ADRs?

Answer 33

Amiodarone:

• Pulmonary fibrosis
• Hepatotoxicity
• Hypo/hyperthyroidism.

Question 34

Where would you most likely find atherosclerosis?

Answer 34

AA > Coronary Artery > popliteal artery > carotid artery

Question 35

MOA of sublingual nitroglycerin?

Answer 35

Used for rapid symptom relief in patients with stable angina

• Primarily venodilators that increase peripheral venous capacitance, thereby reducing cardiac preload and LVEDP and volume.
• Moderate reduction in LV systolic wall stress and a decrease in myocardial oxygen demand, resulting in relief of angina symptoms.
  
  • Modest effect on arteriolar dilation.

Question 36

• Premature coronary artery diseae
• Corneal arcus
• Tendon xanthomas
• Xanthelasmas.

Answer 36

• Heterozygous or homozygous LDL receptor gene mutations, which cause hepatocytes under-expression of functional LDL receptors.
• Can lead to accelerated atherosclerosis and early-onsent coronary artery disease(M.I. at younger age)

Question 37

Echo shows pericardial fluid accumulation with late diastolic collapse of the right atrium.

Answer 37

Cardiac tamponade:

• Beck triad (hypotension, distended neck veins, distant heart sounds)
• Increased H.R.
• Pulsus paradoxus.
  
  • In conditions that impair expansion into the pericardial space (cardiac tamponade), the increased right ventricular volume that occurs with inspirtation leads to bowing of the interventricular septum toward the left ventricle.
• Low-voltage QRS and electrical alternans

Question 38

A neonate presents with sensorineural deafness, cataracts, and PDA. How would this virus affect the mother?

Answer 38

Rubella - toga virus - (+) icosahedral capsid, enveloped, ssRNA.

• Maculopapular rash that begins on the head and neck and spread downward with postauricular lymphadenopathy.
• Generalized lymphadenopathy, postauricular and occipital
• Polyarthritis.

Question 39

A 56-year-old white male presents with unusually dark-brown stool, fever, palpable purpura, and reddish-looking sputum. Biopsy on one of the lesions reveals necrotizing vasculitis.

Answer 39

Microscopic polyangiitis; MPO-ANCA/p-ANCA.

Question 40

A 19-year-old female presents with upper extremity B.P. that is significantly greater than lower extremity B.P., a weak to nonexistent femoral pulse, and rib notching. What are most feared complications of this congenital syndrome?

Answer 40

Coarctation of the aorta; increased risk of cerebral hemorrhages (berry aneurysms), aortic rupture, and possible endocarditis.

Question 41

A patient with PMH of valvular disease (MVP) is recently diagnosed with subacute endocarditis (Osler’s nodes, Janeway’s Lesions). What’s the most likely organism?

Answer 41

Strep viridans

• gram-positive, catalase-negative, alpha-hemolytic, optochin resistant
• Dental carries (S.mutans, S. mitis)
• Subacute bacterial endocarditis (S. sanguinis).
• Forms dextrans that adhere to fibrin and platelets.

Question 42

Aspergillus fumigatus

Answer 42

• Forms septate hyphae (eg, mold) that branch at 45-degree angles.
• Can colonize old lung cavities (from tuberculosis, emphysema, sarcoidosis), forming a “fungus ball”.
• Invasive pulmonary aspergillosis in a patient with febrile neutropeniae (FN): fever, chest pain, cough, dyspnea, and hemoptysis & dense infiltrate involving the upper lung lobe.
  
  • Can spread hematogenously to skin, paranasal sinuses, kidneys, endocardium, and brain.

Question 43

In a patient with acute renal failure, what findings would see you on EKG?

Answer 43

Peaked T waves from hyperkalemia.

Question 44

A 4-year-old boy with a history of intellectual disability and seizures is brought to a physician with a 3-month history of worsening dyspnea. During physical examination, the physician notices numerous acne-like papules on the patient’s face. Echo shows left ventricular outflow obstruction

Answer 44

Tuberous sclerosis.

• Facial angiofibromas
• “Ash-leaf” spots: oval-shaped, depigmented nevus on the lower back.
• Brain hamartomas.
• Cardiac rhabdomyomas
• Renal angiomyolipomas
• Patient most commonly infants.

Question 45

A patient notices edema following radical lymph node dissection. Dx?

Answer 45

Lymphedema due to increased interstitial fluid colloid osmotic pressure.

Question 46

WPW

Answer 46

A congenital cardiac disorder caused by an abnormal conduction pathway that bypasses the AV node and leads to AVRT.

Question 47

MOA & ADRs of sulfonylureas?

Answer 47

1st generation: chlorpropamide, tolbutamide

2nd generation: glimepiride, glipizide, glyburide

• MOA: Close K⁺ channel in B cell membrane –> cell depolarizes –> insulin release via CA²⁺ influx (insulin release independent of blood glucose level).
• Would also increase endogenous C-peptide level (a segment of proinsulin removed during post-translational processing of the protein; stored within the secretory granules).
• ADR: Hypoglycemiae (espeically glyburide since it’s long acting).

Misc: meglitinides: binds to a site(membrane ion channels) different from sulfonylureas.

Question 48

A patient presents with bacterial endocarditis. The cause of the patient’s chest pain is most similar to which of the following disease processes?

Answer 48

Septic emboli dislodged from the valves.

Question 49

Lung biopsy of patient with CHF would reveal what?

Answer 49

Acute: transudate accumulation (an ultrafiltrate of plasma caused by hemodynamic changes) in the alveolar lumen.

vs.

Hemosidern-containing macrophages (macorphages containing golden cytoplasmic granules that turn dark blue with Prussian blue staining) in the alveoli are suggestive of prior episodes of pulmonary congestion and edema that arose due to chronic left heart failure.s

Question 50

A female patient presents with symptoms of (Juxtaductal) coarctation of the aorta. What congenital defect may she have?

Answer 50

Turner syndrome

• XO genetics: loss of paternal X chromsome (meiotic nondisjunction).
• Other findings include bicuspid aortic valve, cystic hygroma, short stature, webbed neck, streak ovaries, and horseshoe kidney (can lead to recurrent UTI).
• IVF may be viable to achieve pregnancy.

Question 51

A neonate born to a diabetic mother is at increased risk of developing?

Answer 51

1. Poor maternal glucose control leads to excessive transplacental glucose transfer to the fetus, which stimulates fetal insulin production –> Leads to beta cell hyperplasia & hyperinsulinemia

• Increased fat deposition & enhanced fetal growth (macrosomia).
• Transient hypoglycemia after birth.

2. Congenital heart malformations: transposition of great vessels.
3. Caudal regression syndrome.

Question 52

Derivatives of aortic arch ?

Answer 52

1st aortic arch:

• CN V
• Maxillary artery

2nd aortic arch:

• CN VII
• Stapedial artery

3rd aortic arch:

• CN IX
• Common carotid artery & prox. internal carotid artery

4th:

• Superior laryngeal branch of vagus (CN X)
• True aortic arch & subclavian artery

6th:

• Recurrent laryngeal branch of vagus (CN X)
• Pulmonary arterys & PDA.

Question 53

Timeline of acute M.I.

Answer 53

0-4 hours: Minimal change.

4-12 hours: Early coagulation necrosis, edema, hemorrhage, wavy fibers.

12-24 hours: Coagulation necrosis and margial contraction band necrosis.

1-5 days: Coagulation necrosis and neutrophilc infiltrate.

• Pericarditis : overlying the necrotic segment of myocardium.

5-10 days: Macrophage phagocytos of dead cells.

• Abrupt rupture of the left ventricle leads to hemopericardium and cardiac tamponade (sudden death).
• Ventricular septal rupture: acute ventricular septal defect and left-to-right shunting
• Papillary muslce rupture: acute onset of severe mitral regurgitation.

10-14 days: Granualtion tissue and neovascularizaiton.

2 weeks ~ 2 months: Collagen deposits/scar formation.

• Dressler’s syndrome.

Question 54

Virulence factor for parainfluenza virus?

Answer 54

The F surface protein cause respiratory epithelial cells to fuse and form multinucleated cells.

Question 55

A soft crescendo-descrendo systolic murmur at the apex and left sternal border while supine that becomes quite pronounced when he stands up.

Answer 55

Hypertrophic cardiomyopathy:

• Biopsy would reveal myofibrillar disarry and fibrosis.
• FMH of premature sudden death.
• Dynamic left ventricular outflow tract (LVOT) obstruction that worsens with decreased LV volume, as can be caused by decreased preload (sudden standing) and/or reduced systemic vascular resistance.
  
  • Vasodilators (eg, dihydropyridine CCB, NO, ACEI) decrease systemic vascular resistance, leading to decreased afterload.
  • Diuretics decrease LV venous filling (Preload).

Question 56

A man presents with fever, weight loss, diffuse myalgias/arthralgias, and abdominal pain. He has areas of ulceration and areas of mottled purple discoloration of lower extremities. PMH includes hepatitis B. Dx & Tx?

Answer 56

Polyarteritis nodosa:

• Episodic multisystem (Kidney, heart, GI, liver) ischemic symptoms sparing the lungs.
• Biopsy: segmental, transmural inflammation of the arterial wall with fibrinoid necrosis.
  
  • Spares PULMONARY ARTERY.

Question 57

• Arm ischemia in the affected extremity (eg, exercise-induced fatigue, pain, parethesias)
• Vertebrobasilar insufficiency (eg, dizziness, vertigo).

Answer 57

Subclavian steal syndrome occurs due to severe stenosis of the proximal subclavian artery, which leads to reversal in blood flow from the contralateral vertebral artery to the ipsilateral vertebral artery.

Question 58

After the administration of drug X, norepinephrine administration results in decreased blood pressure. What could drug X be?

Answer 58

Norepinephrine is an agonist at a1 and B1 receptors but has significantly less action at B2 receptors; it is therefore a potent vasoconstrictor.

Phenoxybenzamine is an irreversible a1 and a2 receptor antagonist that’d produce decreased vasoconstriction.

Question 59

S. pyogenes (GAS).

Answer 59

1. PYR (+) test; anti-streptolysin, anti-DNaseB.
2. Rheumatic fever:

• Molecular mimicry: Antibodies to M protein cross-react with self-antigens.
• Aortic stenosis (in underdeveloped countries) vs. Mitral stenosis (late complication).

3. Scarlet fever
   * Fever/pharyngitis/sandpaper-like rash/circumoral pallor/strawberry tongue.
4. PSGN can occur following infection with S.pyogenes strains that cause either impetigo or pharyngitis. However, rheumatic fever only occur following infection with the strains responsible for pharyngitis. Either way, self-resolves.

Question 60

Digoxin?

Answer 60

1. MOA:

• Blocks Na⁺/K⁺ channels, leading to increased EF
• Increases vagal tone (decreasing heart rate).

2. ADRs:

• N/V, yellow vision.
• Elevated potassium.
• Furosemide causes hypokalemia, which increases Digoxin toxicity.
• Tx: Anti-digoxin Fab fragments as well as Mg2+ supplement.

3. Renally cleared: age-related renal insufficiency is most directly related to toxicity of the agent in the elderly.

Question 61

A patient with refractory SVT is given a medication but subsequently develops QT prolongation. What medication(s) was possible given & ADRs?

Answer 61

Class III agents block outward potassium conductance, which prolongs the repolarization portion of the QT interval but does not affect the QRS portion.

Question 62

Why is hydralazine contraindicated in patients suffering CAD?

Answer 62

Hydralazine vasodilates arteries, greatly reducing B.P., which can lead to reflex sympathetic activation & RAAS axis.

Question 63

Which anti-arrhythmic medications are used in the post-MI period to alter the neurohormonal milieu imposed by the symapthetic nervous system activation, RAAS, and ADH secretion that lead to deleterious ventricular remodeling?

Answer 63

B-B; ACEI

Question 64

Which anti-arrhythmic medication could have induced following EKG?

Answer 64

Class 1A (quinidine), Class III (AIDS)

Question 65

A patient presents with unremitting diarrhea, wheezing, flushing, and a triscupid valve insufficiency. Dx would include?

Answer 65

Carcinoid tumors

• Malignant transformations of neuroendocrine cells, most commonly located in the GI tract (eg, small intestine, rectum, appendix) followed by bronchopulmonary system.
• Symptoms generally do not manifest until metastasis occurs to or beyond the liver, as serotonin undergoes extensive first-pass metabolism in the liver.
• Histology: sheets of uniform cells with a “salt and pepper” pattern.

Question 66

Which hypertensive medications are contraindicated during pregnancy?

Answer 66

ACEI and ARBs should be avoided due to their teratogenicity (kidney and heart).

• Renal dysgenesis
• Fetal anuria/oligohydramnios – > Potter sequence.

Question 67

The mother says her newborn seems “purple,” and she becomes increasingly blue when crying. In addition, she has difficulty feeding and is at 20th percentile for weight. On PE, a harsh systolic murmur at the left upper sternal border is noticed.

Answer 67

Tetralogy of fallot;

• Due to deviation of the infundibular septum.
• Pulmonic stenosis: Determines the degree of dypsnea.
• Right ventricular hypertrophy
• Overriding aorta
• VSD
• Squatting increases systemic vascular resistance, allevating some of the symptoms.

Question 68

Pinealoma?

Answer 68

Tumor of a pineal gland

• Parinaud syndrome: limitation of upward gaze with a downward gaze preference.
• Obstructive hydrocephalus: papilledema, headache, and vomiting.
• Precocious puberty in males: β-hCG (most similar to germ cell tumors).

Question 69

Imaging studies reveal abscesses in the lungs & brain (a headache with a ring-enhancing lesion) in immunocompromised patients. Sputum gram stain shows gram-positive filaments that are weakly acid fast. Dx & Tx?

Answer 69

Nocardia - Trimethoprim.

• MOA: dihydrofolate reductase (+ SMX inhibiting dihydropteroate synthase).
• ADR: megaloblastic anemiae, leukopeniae, granulocytopeniae.s

Question 70

What’s the most common complication of a total thyroidectomy?

Answer 70

Hypoparathyroidism leading to hypocalcemia; perioral numbness, paresthesias of the hands and feet, muscle cramps, positive Trousseau and Chvostek signs.

• Tx with calcitriol (+bisphosphanates).

Question 71

Shares same vector (Ixodes) with Borrelia burgdorferi.

Answer 71

• Acute febrile illness
• Thrombocytopeniae
• Hemolytic anemiae (indirect hyperbilirubinemia, elevated LDH, low haptoglobin)
• Predominantly in northeastern U.S. (e.g., Massachusetts).
• Blood smear: Ring- and cross-shaped intraerythrocytic inclusions.

Question 72

How does reperfusion injury occur within first 24 hours of M.I.?

Answer 72

Generation of free radicals, leading to hypercontraction of myofibrils thorugh increased free calcium influx.

Question 73

Which potential complication of S. pyogenes pharyngitis can be decreased by administration of antibiotics?

Answer 73

Rheumatic fever.

Question 74

Inducers:

• Modafinil.
• Chronic alcohpl abuse.
• St. John’s wort.
• Phenytoin.
• Phenobarbital.
• Nevirapine.
• Rifampin.
• Griseofulvin.
• Carbamazepine.

Answer 74

Inhibitors:

• Acetaminophen, NSAIDs
• Antibiotics/antifungals
• Amiodarone
• Cimetidine
• Cranberry juice
• Omeprazole
• SSRIs (eg, fluoxetine).

Question 75

A patient has history of asthma and smoking. He now presents with O2 saturation of 87% and a respiratory rate of 30/min. Lung auscultation reveals diffuse and elongated end-expiratory wheezes. Which value would be increased initially?

Answer 75

Residual volume.

Question 76

What happens to gas exchange in a patient with emphysema/COPD?

Answer 76

Destruction of alveoli leads to a decreased surface area for gas exchange.

• Decrease in FEV1/FVC
• Decrease in FVC,
• Increase in both TLC and RV due to destruction of interalveolar walls
• Decreas in lung elastic recoil.
• Distal airspace enlargment.

Hypoxia is sensed by cells in the renal cortex that synthesize and release EPO in response.

Question 77

In a patient with hypertrophic cardiomyopathy, an abnormal heart sound is heard in late diastole. Dx?

Answer 77

S4:

• Represents high atrial pressure pushing against stiff LV wall.
• Best heard in left lateral decubitus position.
• Handgrip maneuver impedes the forward flow of blood, increasing left ventricular volume and decreasing murmur intensity due to reduced outflow tract obstruction.
• Valsalva maneuver will increase the murmur (while silencing other murmurs).

REVIEW HEART SOUNDS

Question 78

A patient presents with chest pain and positive Romberg test. Echo reveals aortic valvular insufficiency and a linearly calcified, aneurysmal ascending aorta. Dx?

Answer 78

Late (tertiary) syphilis

• Tabes dorsalis: endarteritis obliterans of the microvasculature supplying the posterior columns and the DRG.
• Argyll Robinson pupil
• Gummas: Painless, indurated granulomatous lesiosn that progress to white-gray rubbery lesions (vs. condylomata lata in secondary syphilis).

Question 79

After injection of an epidural(local) anesthetic, the woman complains of palpitations and severe dizziness. Her ECG is shown to have Morbitz Type II. What was injection?

Answer 79

Amide anesthetic:

• 3° amine local anesthetics penetrate membrane in uncharged form, then bind to ion channels as charged form.
• Can be given with vasoconstrictors (e.g., epinephrine).
• Bupivacaine: causes severe cardiovascular toxicity.

Question 80

A 16-year-old female Japanese exchange student presents with a history of fevers, night sweats, and muscle pain. On physical examination, the patient has extremely weak pulses in her upper extremities.

Answer 80

Takayasu arteritis:

• Granulomatous thickening and narrowing of aortic arch and proximal great vessels.

Question 81

MEN1 vs. MEN2A vs. MEN2B

Answer 81

MEN1:

• Pituitary tumor: galactorrhea
• Pancreatic tumor (e.g., Zollinger-Ellison syndrome develop postbulbar duodenal/jejunal ulcers and pareital cell hyperplasia due to gastrin hypersecretion).
• Parathyroid dysfunction (recurrent kidney stones from hypercalcemia).

MEN2A:

• Parathyroid hyperplasia.
• Medullary thyroid carcinoma.
• Pheochromocytoma.

MEN2B:

• Medullary thyroid carcinoma.
• Pheochromocotyoma.
• Mucosal neuromas/ marfanoid habitus

Question 82

• Refractory ulcers.
• Gastrin rises in response to IV secretin (normally should decrease).

Question 83

alpha2-adrenergic receptor agonist

Answer 83

1. Clonidine: a transdermal medication for refractory HTN.
2. Methyldopa: HTN in pregnancy.

Question 84

Light microscopy reveals large, hypercellular glomeruli with mesangial proliferation and thickening & splitting of BM caused by mesangial ingrowth. Immunofluorescent staining shows granular deposits of C3 and IgG. EM shows subendothelial (immune) deposits in the capillary wall.

Answer 84

MPGN with a “tram-track,” or double-contour appearance of deposits.

• Type I: secondary to hepatitis B or C infection.
• Type II: C3 nephritic factor (IgG antibody that stabilizes C3 convertase –> Persistnet complement activation–> ↓ C3 levels).

Question 85

A 55-year-old man with recurrent arthritis of both knees present to his PCP. Urine turned dark after several hours.

Answer 85

Alkaptonuria

• Congenital deficiency of homogentisate oxidase in the degradative pathway of tyrosine to fumarate
• Bluish-black connective tissue, ear cartilage, and sclerae (ochronosis)
• Urine turns black on prolonged exposure to air
• May have debilitating arthralgias.

Question 86

A patient in her 30s (or 40s) present with flank pain, hematuria, HTN, UTI, and progressive renal failure. An U/S shows numerous cysts in both kidneys and the liver. Where would the mutation be found?

Answer 86

ADPKD; Mutation in PKD1 gene on chromosome 16.

Question 87

• Nephrotoxicity
• Hepatotixicity,
• Tooth discoloration.
• Inhibition of bone growth.

Answer 87

also causes nephrogenic DI.

Question 88

• Fever
• Rash
• Acute renal failure (eg, elevated creatinine, oliguria)
• Eosinophils & IgE

Answer 88

• Sulfonamides: thiazide, loop diuretics.
• NSAIDs.
• Penicillins/ Cephalosporins/ Ciprofloxacin.
• PPI.
• Rifampin.

Question 89

How to calculate GFR? eRPF? FF?

Answer 89

GFR:

• Inulin clearance = GFR = (U_x • V) / P_x
  
  • Total filtration rate of substance = Inulin clearance X plasma concentration.
  • Net excretion: Total filtration rate - tubular reabsorption rate.
• Freely filtered and it is neither reabsorbed nor secreted.
• Creatinine can also be used, but it may slightly overestimate GFR.

Effective renal plasma flow (eRPF):

• U_PAH • V_PAH / P_x
• Between filtration/secretion, there’s nearly 100% excretion of all PAH.
• RBF= RPF (1-HCT).

Fitration Fraction

• FF= GFR / RPF
• Normally 20%

Prostaglandins dilate afferent arteriole; ANG II constrict efferent arteriole (PDA, ACE).

Question 90

A kidney recipient presents with following biopsy after a week. Mechanism?

Answer 90

Acute rejection:

• CD8⁺ T cells activated against donor MHCs.
• Vasculitis of graft vessels with dense interstitial lymphocytic (monocyte) infiltrate.

Question 91

Psychogenic(primary) polydipsia vs. D.I.?

Answer 91

• Hyponatremia (<135 mEq/L) with a low initial urine osmolality.
• A prompt increase in urine osmolality when water is withheld.
• On subsequent administration of ADH, no significant increase in urine osmolality.

Question 92

Which immunosuppressant given to transplant patients is known to cause nephrotoxicity (as evidenced by high creatinine).

Answer 92

Cyclosporine

• Binds to cyclophilin, inhibiting calcineurin, blocking IL-2 production and thus activation of all T lymphocytes.
• Tacrolimus similar MOA.

Question 93

A 63-year-old man with refractory HTN reveals bruit herd on auscultation of the abdomen just to the left of the midline. Dx & Tx?

Answer 93

Renal artery stenosis (caused by atherosclerosis or fibromusculr dysplasia) can lead to HTN (+hypokalemia) due to activation of RAAS.

Question 94

Diabetic nephropathy:

Answer 94

1. Incipient stages:

• Mesangial exapnasion, glomerular basement thickeining, arteriolar hyalinosis
• Microalbuminuria ***

2. Overt DN:

• Mesangial nodules (eg, Kimmelstiel-Wilson lesions)
• Overt proteinuria
• Nephrotic syndrome

Question 95

A 54-year old patient presents with a complaint of GI side effects resulting from the medication he takes to treat RA. Administration of alternative agent would affect renal how?

Answer 95

Celecoxib (COX-2 inhibitor) constricts afferent arteriole by downregulating PGs. This leads to increased preglomerular resistance, subsequently decreasing RBF and GFR.

Question 96

A child presents with cherry-red spots in the macula, splenomegaly, and neurologic deficits. Dx?

Answer 96

Niemann-Pick disease, a lysosomal storage disease in which a sphingomyelinase deficiency results in the accumulation of sphingomyelin.

Question 97

A HIV-positive man presents with swollen legs, foamy urine, and massive proteinuria on urinalysis. Corticosteroids Tx has been unsuccessful. Dx?

Answer 97

FSGS

Question 98

A 10 ~ 12 -year-old boy presents with gross hematuria (tea/cola-colored urine), edema, and HTN. Urine studies reveal presence of RBCs, proteins, and RBC casts. Serum studies shown an elevated creatinine, streptococcal antibodies, and decreased C3. DX?

Answer 98

• Subepithelial immune complex deposits.
• IF: “starry sky” granular apperance due to IgG, IgM, and C3 deposition along GBM and mesangium.
  
  • Low C3 level ***
• Usually develops 1-3 weeks after streptococcal pharyngitis & impetigo (as opposed to within 5 days in IgA nephropathy).
• Tx: Supportive therapy only; resolves spontaneously.

Question 99

TMP-SMX: used to treat susceptible organisms that cause urinaty tract, GI, and skin infections:

• P. jiroveci
• T. gondii
• Nocardia.

Answer 99

5-days of nitrofurantoin (Trimethoprim-sulfamethoxazole is contraindicated due to sulfa allergy).

Question 100

A medication prescribed for diabetes insipidus and bedwetting in children can also treat ?

Answer 100

Desmopressin:

• Can also treat von Willebrand disease or hemophilia A.

Question 101

A 35-year-old woman presents with right flank pain, N/V, fever. CVA tenderness is positive. Laboratory results reveal WBC casts in the urine. Dx ?

Answer 101

Acute pyelonephritis with neutrophils (PMN) infiltration in renal instititum.

• Vesicoureteral reflux in context of cystitis.

Question 102

A child presents with microcephaly, moderate to severe intellectual disability, and a high-pitched crying/meowing.

Answer 102

Cri-du-chat syndrome; congential microdeletion of short arm of chromosome 5.

Question 103

A 20-year-old female patient is currently taking a medication for her severe cystic acne. What should she be tested for beforehand?

Answer 103

A (-) pregnancy test and two forms of contraception before isotretinoin is prescribed.

Question 104

A patient suffering from hypovolemic shock would present with similiar plasma renin concentration as patient with which enzyme deficiency?

Answer 104

21 alpha-hydroxylase.

• Male: normal genitalia; salt-wasting or precocious puberty
• Female: Increased androgen levels lead to ambiguous genitalia (virilization).
• High serum level of 17-hydroxyprogesterone ***
• Tx: low-dose of exogenous corticosteriods to suppress ACTh secretion.

Question 105

In a patient with renal artery stenosis, which antihypertensive medication will require careful monitorning of renal function?

Answer 105

ACEI

Question 106

A 7-year-old boy presents with severe pelvic pain. His creatinine level is 1.7 mg/dL, and levels of lysine and arginine in the urine are elevated.

Answer 106

Cystinuria

• Cystine-reabsorbing PCT transporter loses function, causing cystinuria. Transporter defect also results in poor reabsorption of ornithine, lysine, arginine (COLA)
• ↓ pH (↑ H⁺ excretion).

Question 107

SLE nephritis presenting with “wire-loop” appearance

Answer 107

Subendothelial and sometimes intramembranous IgG-based ICs often with C3 deposition.

Type III hypersensitivity:

• Antibody-antigen immune complex disease
• Serum sickness

Question 108

Which diuretic is useful for altitude sickness (combating respiratory alkalosis), glaucoma, and psuedotumor cerebri?

Answer 108

Acetazolamide.

Question 109

• History of allergies (atopic patients).
• Asthma, sinusitis, skin nodules or purpura, peripheral neuropathy (eg, wrist/foot drop).
• Granuloamtous, necrotizing vasulcitis with eosinohpilia.

Answer 109

• RPGN: Pauci-immune.
• P-ANCA.

Question 110

3 weeks after having a cold, a 22-year-old man presents with hemoptysis. X-ray of the chest shows diffuse opacities in both lower lung fields, and U/A reveals RBCs in the urine. Dx?

Answer 110

Goodpasture syndrome (which can present following viral infections of the pulmonary system).

• Type II hypersensitivity reaction.
• Antibodies against type IV collagen in a linear fashion found in alveolar & GBM
• RPGN (crescent): Fibrin escape into Bowman’s space.

Question 111

A 55-year-old man with a 10-year history of well-controlled HTN and mild CHF presents with decreased sex drive and enlargement of his breast. Dx?

Answer 111

Spironolactone

• A weak androgen receptor antagonist in addition to being an aldosterone receptor antagonist.
• ADR
  
  • Gynecomastia.

Eplerenone is a newer & more selective aldosterone antagonist that produces fewer endocrine side effects.

Question 112

An 18-year-old man presents with HTN. Laboratory tests show a potassium level of 3.2 mEq/L. Further work-up reveals very low serum renin and low serum aldosterone levels. Dx & Tx?

Answer 112

Liddle syndrome:

• Presents like hyperaldosteronism, but aldosterone/renin level is nearly undetectable.
• ↑ Na⁺ reabosrption in collecting tubules: results in HTN, hypokaelmia, metabolic alkalosis.
• Similar to Syndrome of Apparent Mineralcocorticoid Excess (hereditary deficiency of 11B-hydroxysteroid dehydrogenase).
• Tx: ENaC inhibitor, triamterene

Question 113

Chronic Kidney Disease

Answer 113

MAD HUNGER:

• Metabolic Acidosis
• Dyslipidemia
• Hyperkalemia
• Uremia (N/V, pericarditis, asterixis, encephalopathy, platelet dysfunction)
• Na/H2O retention (HF, pulmonary edema, HTN)
• Growth retardation
• EPO failure (NORMOCYTIC ANEMIA WITH NORMAL PLATELETS/WBC COUNTS).
• Renal osteodystrophy (osteomalacia):
  
  • Due to phosphate retention & Decreased 1,25-dihydroxyvitamin D leading to secondary hyperparathyroidism.

Question 114

In any scenario manifesting in an obtunded alcoholic, aspiration pneumonia should be at the DDx. Such pulmonary disturbance is known to cause?

Answer 114

1. Aspiration penumoniae:

• The cavitary lesion with air-fluid levels: lung abscess.
• PMH of dementia and stroke
• Superior regions of the lower lobes and posterior regions of the upper lobes are the most dependent locations in the lungs of supine individuals.
• Presents with systemic symptoms.
• (Oropharyngeal) anaerobic bacteria: Fusobacterium, Peptostreptococcus, Bacteroides.

2. May also have SIADH (hyponatremia with decreased plasma osmolarity).

Question 115

Which antihypertensive medication is indicated for pregnancy?

Answer 115

Hydralazine, labetalol, methyldopa, nifedipine.

Question 116

A patient with PMH of high cholesterol presents with severe muscle aches, urinary frequency, and “strange-colored urine”. He has been drinking large amounts of grapefruit juice & taking a statin. His serum creatinine level is 2.0 mg/dL. Dx?

Answer 116

Rhabdomyloysis brought on by statin.

Question 117

A 72-year-old man presents with abdominal pain and distention. He has had a problem with starting a urine stream for the past year. His PMH is significant for diabetes, HTN, and CAD. His serum creatinine is 2.4mg/dL. When a foley catheter is placed, urinary flow begins immediately. Dx?

Answer 117

BPH: Urinary frequency, nocturia, hesistancy, weak urinary system

• Alpha adrenergic antagonist: terazosin, tamsulosin are smooth muscle relaxants that work on the dynamic component of bladder outlet obstruction.
• 5-alpha reductase inhibitors (finasteride, dutasteride) can reduce prostate volume.
  
  • Can also treat androgenetic alopeciae.

Question 118

How does angiotensin II affect acid/base status?

Answer 118

AT II stimulates HCO^3- reabsorption in the PCT by increasing the rate of H⁺ recycling across the luminal cell membrane via the Na⁺-H⁺ exchanger.

Question 119

A 45-year-old woman recently diagnosed with AML is undergoing chemotherapy with a course of methotrexate and cytarabine. She now complains of oliguria. Her CBC shows: hyperkalemia, metabolic acidosis, increased BUN/Cr, and hypocalcemia. Dx & Tx?

Answer 119

Acute kidney injury secondary to tumor lysis syndrome. Treat with:

• Allopurinol: Xanthine oxidase inhibitors.
  
  • ↑ concentrations of azathioprine nad 6-MP.
• Rasburicase/ Pegloticase: Recombinant uricase catalyzing uric acid to allantoin.

Question 120

A 12-year-old girl is brought to the clinic by her parents after she’s found to have HTN by her school nurse. Patient has had several epsidoes of fever and abdominal pain. Renal ultrasound reveals dilated calcyes with overlying cortical atrophy bilaterally, mostly in the upper & lower poles. DX?

Answer 120

Acute pyelonephritis caused by vesicoureteral reflux:

• Renal scarring most commonly @ the upper & lower poles of the kidney.
• VUR can lead to loss of neprhons and secondary HTN.
• “Thyroidization”.

Question 121

An unconsciouss 55-year-old woman is brought to the ER by paramedics. Her PMH is significant for HTN, ADPKD, and high cholesterol level. On P.E., the patient’s left eye is deviated inferolaterally, and the pupil is dilated and unreactive.

Answer 121

1. A berry aneurysm is a thin-walled outpouching at a cerebral artery branch point that can rupture, leading to SAH.
2. Aneurysms involving the posterior communicating artery may cause an isolated oculomotor nerve (CN III) palsy.

• Mydriasis (due to superifical parasympathetic fiber damage)
• Diplopia
• Ptosis
• “Down and out” deviation.

Question 122

• Flesh-colored skin nodules on neck & back: Cafe-au-lait spots
• Multiple frckels, nodules, and pigmented lesions: Neurofibromas (benign nerve tumor sheath in schwann cells).
• Pigmented iris hamartomas: Lisch noduels.
• Skeletal abnormalities (eg, scoliosis).
• Optic nerve gliomas.

Answer 122

The mutated gene resides on chromosome 17 and encodes a GTPase-activating protein that decreases the activity of Ras.

AUTOSOMAL DOMINANT

Question 123

Signs & symptoms of NF2?

Answer 123

1. Bilateral acoustic schwannomas

• CN V: loss of facial sensation & paralysis of the muscles of mastication
• CN VII: facial muscle paralysis (upper & lower); loss of taste in the anterior 2/3 of the tongue, decreased lacrimation/salivation, hyperacusis (paralysis of the stapedius)
• CN VIII: sensorineural hearing loss & tinnitus
• S-100

2. Juvenile cataracts
3. Meningiomas, and ependymomas: peripheral neuropathy, gait disturbance, and muscle wasting.

AUTOSOMAL DOMINNAT mutation on Chromsome. 22

Question 124

A 40-year-old male who visited the family’s lake house 5 days prior now presents with N/V, seizures, and altered mental status. A CSF sample is obtained with an opening pressure of 300cm H2O, WBC > 1000, with PMN predominance, erythrocyte count of 1000/uL, decreased glucose, and elevated protein. A wet mount of the CSF demonstrates motile organisms.

Answer 124

Naegleria fowleri can present with a rapidly progressing meningoencephalitis. Gains access to the CNS through the cribriform plate.

Question 125

A 52-year-old construction worker comes to the ER after being accidentally shot in the arm with a nail gun. Biceps reflex is absent. Which following sensory deficits is most likely seen in this injury?

Answer 125

Musculocutaneous nerve injury would lead to a loss of sensation in the lateral forearm.

• C5-C6 spinal nerves mediate the biceps and brachioradialis reflexes.

Question 126

After total thyroidectomy, a patient complains of hoarseness. Laryngoscopy shows that the left vocal cord is shortened and held in adduction. Dx?

Answer 126

During thryoid surgery, recurrent larygneal nerve may be damaged due to its proximity to the inferior thyroid artery. Unilateral nerve injury often causes hoarseness, whereas bilateral injury may cause inspiraotry stridor and respiratory distress.

The cricothyroid muscle is instead innervated by superior laryngeal nerve/external laryngeal brach (derivative of 4th pharyngeal arch).

Question 127

A patient taking antiepileptic presents with fevers, productive cough, and pleuritic chest pain. CBC shows dangerously low WBCs and absolute neutrophil count. What medication is he most likely taking?

Answer 127

Carbamazepine

• Blocks Na⁺ channels
• Partial; tonic-clonic
• ADRS: Blood dyscrasias (bone marrow suppression, including anemiae, agranulocytosis, and thrombocytopeniae)- monitor with CBC;
• 1st line for trigeminal neuralgia.

Question 128

A patient presents with “pill-rolling” tremor, hypokinesia, shuffling gait, cogwheel rigidity, and postural instability. Dx?

Answer 128

Parkinson disease

• Loss of dopaminergic neurons (eg, depigmentation) of substantia nigra pars compacta.
• Lewy body: Composed of α-synuclein (intracellular eosinophilic inclusions).

Question 129

Lyme disease

Answer 129

Caused by Borrelia burgdorferi, which is transmitted by the Ixodes deer tick.

• Facial nerve palsy
• Arthritis
• Cardiac block
• Erythema migrans

Tx: doxycycline.

Question 130

Receptors for neurotransmitter that is most deficient in Parkinson’s Disease are most concentrated in ?

Answer 130

Caudate/putamen; striatum.

Question 131

Lateral medullary syndrome, or Wallenberg syndrome,

• Infarct of the posterior inferior cerebellar artery (PICA; a branch of vertebral artery).

Answer 131

• Ipsilateral face numbness: trigeminal nucleus
• Contralateral limb numbness with loss of pain and temperature sensation: compromise of spinothalamic tract and medial lemniscus.
• Nucleus ambiguus (CN IX, X, XI): Dysphagia, hoarseness, ↓ gag reflex, hiccups.
• Ipsilateral Horner syndrome: compromise of sympathetic fibers.
• Disequilibrum and diplopia: from compromise of the vestibular nuclei.

Question 132

A 27-year-old man is thrown from a motorcycle into a tree. On physical examination, he has very limited abduction of his left shoulder and flexion of his left elbow. On observation, the left shoulder is held in internal rotation, with pronated forearm and extended elbow.

Answer 132

Erb palsy, due to downward compression of the shoulder and damage to the C5 and C6 nerve roots of the brachial plexus.

Question 133

The patient presents with symptoms of decreased breath sounds at the right lung apex, right upper extremity pitting edema, diminished grip and triceps reflex, and a narrowed right palpebral fissure (ptosis).

Answer 133

Pancoast/superior pulmonary sulcus tumor:

• Cough
• Hoarseness
• Severe left-sided shoulder pain
• Horner’s syndrome: ptosis, miosis, and anhydrosis.

Question 134

In superior vena cavae syndrome caused by mediastinal mass (e.g., lung cancer), dyspnea, cough, swelling of the face/neck/upper extremities would be more prominent.

Question 135

A 84-year-old patient presents with urinary incontinence, ataxia (wide-based gait, or “magnetic” gait), and dementia. This is an example of ?

Answer 135

“Wet, Wobbly, Wacky”:

Normal pressure hydrocephalus caused by either: increased CSF production by choroidal tumors or impaired CSF resorption by arachnoid granulations (superior sagittal sinus is the main location of CSF return via arachnoid granulations).

• Urinary (urge) incontinence caused by stretching of descending cortical fibers: Decreased inhibitory control of bladder contractions by the frontal lobe.

Question 136

Which antibiotic is related to causing a seizure in a patient?

Answer 136

Antibiotic-related seizure complications are most often associated with B-lactams.

Imipenem, co-adminstered with cilastatin to decrease renal metabolism, is the first-line therapy in the Tx of acinetobacter and enterobacter species infection.

ADRs include GI distress, thrombophlebitis, skin rashes, and seizures.

Question 137

Bronchoalveolar lavage specimen stained positively with Ink Stain. Dx & Tx?

Answer 137

India ink shows budding yeasts with thick capsules & stains red with mucicarmine.

• Latex agglutination: polysaccharide capsule antigen of Cryptococcus
• Primarily focus on the lungs ***
• Meningoencephalitis would present as lymphocytosis, decreased glucose, and increased protein on lumbar puncture.

Amphotericin B should be started as induction therapy along with flucytosine, which works by blocking fungal precursors from converting into pyrimidines.

• Binds ergosterol; forms membrane pores that allow leakage of electrolytes.
• Supplement K⁺ and Mg²⁺ because of alterned renal tubule permeability.

Question 138

Patellar reflex

Answer 138

Mediated by L3, L4.

Question 139

Following autopsy reveals?

Answer 139

Amyotrophic lateral sclerosis

• Degeneration of the anterior horns and lateral corticospinal tracts, resulting in both UMN and LMN lesions.
• Mutations in the SOD1 gene.
• Tx: riluzole.

Question 140

A patient with PMH of bloody diarrhea just a few weeks ago now presents with acute, progressive, and symmetric ascending muscle weakness/paralysis in addition to absent ankle jerk reflexes. Dx & complication & tx?

Answer 140

GBS (endoneural inflammatory infiltration)

• caused by Campylobacter jejuni, a curved, oxidase-positive, gram-negative bacterium that grows at 42°
• Organism acquired from domestic animals (cattle/sheep/dogs/chickens) as well as contaminated food.
• CSF profile would show increased protein but normal WBC count (albuminocytologic)
• respiratory paralysis leading to hypoventilation (respiratory acidosis).
• Tx: plasmaphoresis or IG.

Question 141

Thrombolytic therapy is contraindicated in which patients?

Answer 141

• Active bleeding
• History of intracranial bleeding
• Recent surgery
• Known bleeding diatheses
• Severe HTN: Systolic blood pressure > 185 mm Hg or a diastolic blood pressure of >110 mm Hg.

Question 142

Lesion in following CN would manifest as ?

Answer 142

CN 5: Trigeminal nerve

• Mastication and facial sensation.

Question 143

Answer 143

Wilson disease, an AR disorder caused by a mutation of the ATP7B gene on chromosome 13 leading to decreased secretion into the bile of a metal that forms free radicals.

• Hepatic: acute liver failure, chronic hepatitis, cirrhosis
• Neurologic: Parkinsonism, gait distrubance, dysarthria
• Psychiatric: Depression, personality change
• Decreased ceruloplasmin
• Kayser-Fleischer rings (cornea).

Tx: Chelators (eg, D-penicillamine, trientine).

Question 144

A 36-year-old man presents with a long history of severe headaches, which started when he was 24. The headaches occur nightly for several weeks and usually last about 30 minutes, followed by a few months without headaches. The pain is always localized to one side of his head. The physician instructs the patient to use an oxygen mask at the onset of the headaches to help relieve the pain.

Answer 144

Cluster headaches, accompanied by lacrimation/nasal congestion/conjunctival injection.

• treat with verapamil (CCB), 100% oxygen mask.
• treat with sumatriptan, a 5-HT_1B/1D agonist (can rarely cause coronary vasoconstriction).

Question 145

Using the diagram, which letter corresponds to what drug?

Answer 145

A: Metyrosine.

• blocks the rate-limiting step of catecholamine synthesis (eg, tyrosine hydroxylase).

B: Reserpine.

C: Amphetamines.

D: Cocaine.

E: Epinephrine.

Question 146

A female patient presents with bitemporal hemianopsia and a wet stain in her bra. The most likely source of her visual field defect interfers with fibers that originate from?

Answer 146

The most likely scneario is prolactinoma causing bitemporal hemianopia.

The nasal retina is responsible for the temporal visual fields, and the temporal retina is responsible for medial visual fields.

Question 147

Which endocrine hormones bind to cAMP? Intracellular receptors (zinc-finger motif)? Receptor tyrosine kinase? Nonreceptor tyrosine kinase?

Answer 147

1. cAMP: FSH, LH, ACTH, TSH, CRH, hCG, ADH (v2), MSH, PTH, calcitonin, GHRH, glucagon, histamine.
2. IP₃: GnRH, Oxytocin, ADH (v1-receptor), TRH, hstamine (H1), ANG II, Gastrin.
3. Intracellular receptor (zinc-finger: DNA binding domain): Progesterone, estrogen, testosterone, cortisol, aldosterone, T3/T4, vitamin D.
4. Receptor tyrosine kinase: Insulin, IGF-1, FGF, PDGF, EGF.
5. Nonreceptor tyrosine kinase (JAK/STAT): Prolactin, cytokines, GH, G-CSF, EPO, Thrombopoietin

Question 148

A 3-year-old child presents with abdominal distension and a firm, irregular mass that crosses the midline. Urinalysis is positive for HVA and VMA. Dx & complication?

Answer 148

NEUROBLASTOMA.

Pathogenesis:

• Neural-crest origin
• Involves adrenal medulla, sympathetic chain.

Clinical features:

• Median age <2
• Abdominal mass
• Periorbital ecchymoses (orbital metastases)
• Spinal cord compression from epidural invasion
• Opsoclonus-myoclonus syndrome.

Diagnostic findings:

• Biopsy reveals homer-wright rosettes (~medulloblastoma).
• Elevated catecholamine metabolites.
• N-myc gene amplification.

Question 149

Biopsy of a thyroid is shown. Dx?

Answer 149

Papillary carcinoma:

• Papillary clusters. ***
• “Orphan-Annie”: Large cells with overlapping nuclei containing finely dispered chromatin + intranuclear inclusions and grooves.
• Psammoma body, a concentrically calcified lamellated inclusion.
• Associated with RET and BRAF mutations, childhood irradiation.
• Usually cold lesions

Question 150

A 3-month-old child is brought to his pediatrician’s office for a check-up. The child has a rather pale complexion. He has a social smile but does not hold his head up on his own or make noises. Brisk reflexes are noted, and he has a rash. The mother reports that he also has a strange odor. Dx?

Answer 150

Phenylketonuria:

• Most commonly from a deficiency of phenylalanine hydroxylase (Phe —>Tyr): uses tetrahydrobiopterin as a cofactor.
• Findings: intellectual disability, growth retardation, seizures, fair skin, eczema, musty body odor, hypopigmentation of substantia nigra/locus ceruleus/vagal nucleus dorsalis.
• Tx: A diet low in phenylalanine with tyrosine supplementation.
• Autosomal recessive (1/4)

Question 151

PKU

Answer 151

Dihydrobiopterin reductase deficiency:

• Downstream deficiencies of neurotransmitters (e.g., dopamine, NE, epinephrine, serotonin) lead to progressive neurological deterioration in these patients.
• Problems persist even with dietary modifications.
• Decreased BH4 causes lower levels of dopamine, which lead to increased prolactin levels.

Question 152

Large, flinging movements of a patient’s arm is due to?

Answer 152

Hemiballismus;

Decreased activity of the STN leads to decreased activity of GPi, and subsequent increased activity of the thalamus.

Question 153

• Headache, N/V, photophobia.
• Preceded by flulike illness.
• Fever.
• Stiff neck.

Answer 153

Bacterial: elevated opening pressure, elevated WBC count (with PMN predominance), elevated protein, decreased glucose.

• Infants (0-6 months): GBS, E.coli, L. monocytogene
• 6 months- 6 year: S. Pneumoniae**, N. Meningitidis, H.influenza (incidence has dramatically decreased due to type B vaccines;** #1 cause of epiglottitis),
• College age (19-20 y.o) : S. Pneumoniae, N. Meningitidis
• Adult: S. Pneumoniae (otitis media)

Question 154

• Prodrome: Fever, chills, malaise, paresthesias.
• Acute neurologic symptoms: Hydrophobia, pharyngeal spasm, hyperactivity of ascending paralysis.
• Coma & Death.

Answer 154

• Rhabdoviridae, an enveloped ssRNA;
• Travels via axonal transport and direct infection.
• Glycoprotein-spiked envelope allows attachmet to Ach receptor of muscle cells.

Question 155

A 70-year old woman with a history of a-fib presents with trouble walking. Physical exam reveals unilateral leg weakness and decreased sensation, but no visual deficits.

Answer 155

Lesion in A, ACA.

Question 156

Infarction of ASA causing medial medullary syndrome would manifest as?

Answer 156

1. Occlusion of the ASA at the level of the medulla oblongata is responsible for medial medullary syndrome.

• Lateral corticospinal tract: contralateral paralysis and hyperreflexia of upper & lower extremities.
• Medial lemniscus: loss of proprioception and vibratory sensation.
• Caudal medulla (CN XII): ipsilateral hypoglossal dysfunction (tongue deviates ipsilaterally)

2. Damage to the ASA at more caudal levels of spinal cord leads to a different clinical presentation, called anterior spinal artery syndrome.
   * Complete loss of strength below the level of injury with loss of pain & temperature sensation, but preserved vibratory senses.

Question 157

• Combative behaviour.
• Confusion.
• Hallucinations.
• Nystagmus/ataxia.

Answer 157

• NMDA receptor antagonist.
• Also inhibits the reuptake of NE/Dopamine/serotonin.
• Tx: Benzodiazepines.

Question 158

Tx for Alzheimer’s disease include?

Answer 158

NMDA receptor antagonist & helps prevent excitotoxicity: Menantine

AChEI: donepezil, galantamine, rivastigmine, tacrine, physostigmine.

Question 159

Positive Romberg test would indicate?

Answer 159

Due to impaired proprioception, suggesting a lesion in the DCML tract, which is the pathway responsible for carrying information on proprioception, vibration, and light touch.

Question 160

An 86-year-old right-handed woman presents to the ER with right-sided paralysis of the arm and face with forehead sparing. Her speech is very slow and lacks a normal grammatical structure. She appears frustrated.

Answer 160

Broca’s aphasia; infarct in left inferior frontal gyrus.

Question 161

What’s the significance of ventral posteromedial nucleus of the thalamus (VPM)?

Answer 161

Facial sensory pathways corresponding to the contralateral trigeminal distribution pass through VPM.

When damaged, the contralateral face is anesthetic.

Question 162

• The lesser and greater cavernous nerves arise from the prostatic plexus and pass beneath the pubic arch to inntervate the corpora cavernosa of the penis and urethra.
• Prostatectomy or injuryt o the prostatic plexus can cause ED.

Question 163

Dx?

Answer 163

Oligodendroglioma

• Relatively benign tumors that primarily affect the frontal lobes of adults and have a tendency to calcify.
• “Fried eggs” with perinuclear halos and “chicken wire” capillary patternings.
• Symptoms include seizures, headache, personality changes, and neurologic deficits.

Question 164

• Binds to 30S and prevent attachement of aminoacyl-tRNA.
• Clinical use: Borrelia burgdorferi, M. Pneumoniae, Ricketssiae, Chlamydia (accumulate intracellularly).
• ADRs: GI distress, discoloration of teeth and inhibition of bone growth in childrne, photosenstivity.

Question 165

A patient is asked to flex his MCPs. Where would the lesion be?

Answer 165

Inflammation of the ulnar nerve leads to weakness of:

• the 4th and 5th lumbricals, which flex the MCP and extend the ICP joints,
• the medial half of the flexor digitorum profundus
• the dorsal and palmar interossei, which abduct and adduct the digits.

Question 166

Unvaccinated children are at risk for infection by the polio virus, which can invade the intestine and the motor neurons and may result in neurologic sequelae such as respiratory muscle paralysis.

Answer 166

Paralytic poliomyelitis is the most feared complication - a result of destruction of LMN in the anterior horn of the spinal cord.

Question 167

A patient with Parkinson’s disease is given an antiviral agent. MOA?

Answer 167

Amantadine, an antiviral medication used in the Tx of influenza and rubella (impairs uncoating of the influenza A virion).

It also promotes the synthesis and release of doapmine and prevents its reuptake.

Enhances the effect of endogenous dopamine.

Question 168

• Loss of pain and temperature in a cape-like distribution (upper back, shoulders, arms)
• An MRI of the spinal column shows dilation within the cervical spinal cord. Can expand to involve:
  
  • Lower extremity weakness and hyperreflexia (UMN) by affecting the lateral corticospinal tract
  • Loss of position and vibration senses in the feet due to involvement of the DCML.

Answer 168

Syringomyelia : commonly affects the C8-T1 level; can impinge on the crossing fibers of the spinothalamic tract.

Associated with Type 1 Chiari malformation (a downward herniation of the cerebellar tonsils).

• Can exapnd to damage motor neurons of the ventral horn.

Question 169

A 35-year-old man undergoes a surgical procedure in which the anesthesiologist uses halothane for anesthesia and succinylcholine, a depolarizing agent, for neuromuscular blockade. During this procedure, the patient develops muscular rigidity and pyrexia.

Answer 169

Malignant hyperthermia

• Mutations in voltage-sensitive ryanodine receptor: RyR channelopathy.
• Tx: dantrolene.

Question 170

A laborer on a fruit farm is brought to the ER by a coworker because he’s having diarrhea and difficulty breathing after the lunch break. His H/R is 50/min, BP is 80/60 mm Hg, respiratory rate is 23/min, and temperature is 36.9. On exam, he’s diaphoretic, drooling, and unable to answer questions coherently.

Answer 170

Dx: Organophosphate poisoning (permanently inactivate AChE, activating both nicotinic & muscarinic).

• Diarrhea/defacation
• Urination
• Miosis
• Bronchospasm
• Bradycardia
• Excitation of skeletal muscle & CNS
• Lacrimation
• Sweating/ salivation

Tx: Atropine, Pralidoxime (regenerates AChE)

• Atropine does not reverse muscle paralysis (nicotinic stimulation).

Question 171

Opioid intoxication & withdrawal would present as?

Answer 171

1. Intoxicaton

• Coma, pinpoint pupils, and respiratory depression
• Methadone (a full mu-opioid receptor agonist; long 1/2): the control of chronic pain and in opioid withdrawal and maintenance treatment of addiction.
• Buprenorphine: partial opioid agonist that binds with high affinity (potency) and can prevent binding of other opioid medications.
• Naloxone (pure opioid receptor antagonist with greatest binding affinity to mu receptors) to treat opioid overdose & intoxication.

2. Withdrawal

• Dilated pupils
• Yawning
• Lacrimation
• Piloerection
• • Nonspecific GI symptoms (N/V, abdominal pain, hyperactive bowel sounds).

3. Responsible for majority of overdose deaths in the U.S.

Question 172

An infant presents with prominent epicanthal folds, single palmar crease, and intellectual disabiltiy. Dx & complications?

Answer 172

1. Down syndrome
   * ↓AFP; ↑b-hCG & inhibin A
2. Increased risk of:

• Alzheimer’s disease
• ALL/AML: anemia; thrombocytopeniae leading to fatigue, easy bruising and anemia.
• Duodenal atresia, Hirschsprung disease
• Endocardial cushion defects (eg, defects in the lower part of the interatrial septum and the interventircular septum).

3. Trisomy 21

• Segregation error (nondisjunction) during meiosis I anaphase may cause an abnormal number of chromosomes in the daughter cells >
• Robertsonian translocation (entire long arm of one chromosome 21 is translocated to the long arm of an acrocentric chromosome, 14)
• Postfertilization mosaicism.

Question 173

A 40-year-old man was admitted to the neurology service for evaluation of persistent numbness over his left lower jaw and face. His jaw deviates to his left when attempting to open his mouth. Nerve responsible for this exits skull via?

Answer 173

V₃- Foramen ovale.

Question 174

Correcting serum Na⁺ too fast:

• “From low to high, your pons will die”

Answer 174

Osmotic demyelination syndrome, eg “Locked-in syndrome”

Question 175

After a brain-tumor resection, a patient presents with agraphia, acalculia, finger agnosis, and right-left disorientation. Dx?

Answer 175

Gertsmann syndrome

• Dominant (left) parietal lobes.

Question 176

Pheomochromocytoma is related to which embryologic structure?

Answer 176

Neural crest

• Melanocytes
• Odontoblasts
• Tracheal cartilage
• Enterochromaffin cells
• Laryngeal cartilage
• Parafollicular cells of the thryoid (eg, Calcitonin)
• Adrenal medulla & ganglia
• Schwann cells
• Spiral membrane (aorticopulmonary septum & endocardial cushions)

Stains for S-100.

Question 177

A patient with a severe cough, hemoptysis, and a 40-pack-year history of smoking presents with ptosis, miosis, and anhidrosis. Possible DDx?

Answer 177

Horner’s syndrome secondary to Pancoast tumor.

• Frequently strangulate and/or damage the 2nd-order preganglionic sympathetic neurons that pass through the inferior cervical or stellate ganglion and ascend to eventaully synapse in the superior cervical ganglion.

Question 178

A gram-positive bacilli, with narrow B-hemolysis on sheep blood agar, that causes sepsis and meningitis in children & immunocompromised (HIV) adult.

Answer 178

Listeria, which can be transmitted via unpasteurized dairy products:

• As a facultative intracellular (tumbling motility) organism, it is best controlled by the cell-mediated arm of the immune system. In HIV/AIDs, the cell-mediated response is compromised as indicated by the low CD4+ count.
• Can survive refrigerated temperature.
• Resistant to cephalosporins(eg, cefotaxime, ceftriaxone) but susceptible to ampicillin.
• Transmitted transplacentally or via vaginal contact during delivery.

Question 179

Antihistamines (diphenhdyramine, doxylamine)

TCA (amitriptyline, imipramine)

1st-generaiton low-potency antispychotics (chlorpromazine, thioridazine)

2nd-generation antipsychotics (clozapine)

Antiparkinson drugs (benztropine)

Belladonna alkaloids (Atropine)

Answer 179

• Increased body temperature
• Decreased secretions (eg, mucous membranes, sweat glands)
• Flushed skin
• Cycloplegia, mydriasis
• Altered mental status
• Urinary retention.
• Tx: physostigmine, AChEI; preferred over neostigmine due to its ability to cross BBB.

Question 180

A patient with deep laceration on his left cheek presents with drooping of left corner of his mouth. Dx?

Answer 180

Buccal branch of the CN VII sustained an injury;

Exits through IAM–> stylomastoid foramen.

Question 181

A 73-year-old woman undergoing chemotherapy presents with extremely painful blistering lesions behind the left ear and on the left side of the back of her head. Dx & Tx?

Answer 181

VZV reactivation in C2 DRG.

Tx: Acyclovir, a nucleotide analogue that must be activated by viral thymidine kinase.

• Obstructive crystalline nephropathy and acute renal failure if not adequately hydrated.

Question 182

A 6-month-old infant presents with recurrent bacterial/viral infections, constant diarrhea, failure to thrive, full anterior fontanelle and a white coating on the tongue that can be scraped off (thrush). CXR demonstrats an absent thymic shadow. Dx?

Answer 182

SCID, secondary to adenosine deamine deficiency (causes T, B, and NK cells to dysfunction)

• Absence of thymic shadow (CXR), germinal centers (lymph node biopsy), and T cells (flow cytometry).

Question 183

• Sudden impairment of consciousness
• Unresponsive to tactile/verbal stimulation
• Automatisms (eg, rhythmic blinking or rpetitive lip smacking, may occur).
• EEG: 3-hz spike-wave discharges during episodes.

Answer 183

Ethosuximide:

• T-type Ca²⁺ channels blocker.
• Can potentially cause Stevens-Johnson syndrome.

Valproic acid: Second-line Tx for absence epilepsy.

Phenytoin can treat all but absence (partial, tonic-clonic, and status epilepticus).

Question 184

Rapid progression of neurologic & psychiatric symptoms (over the course of just a few months), paired with strong startle response and jerking movements are consistent with?

Answer 184

CJD

• Corneal transplants, implantable electrodes, or preparation of GH.
• Associated with PrP that’s resistant to enzymatic digestion.
• Spongiform encephalopathy: vacuoles form in the cytoplasm of the neutrophils and neurons.

Question 185

Multiple Sclerosis is a clinical diagnosis characterized by at least two separate attacks with two different clinical lesions. The most common presentations include

Answer 185

• Asymmetric sensory and motor deficits, often in the extremities (+loss of bladder function)
• Optic neuritis: eye pain, blurred vision, and afferent pupillary defect.
• Defect in MLF (paramedian pontine reticular formation projects to ipsilateral lateral rectus muscle and contralateral medial rectus muscle).
• Cerebellar abnormalities, which include ataxia, nystagmus, and tremor.
• Worse in hot temperature.
• Diagnosed by presence of oligoclonal bands.
• RELAPSE-REMITTING.
• Tx: B-inteferon produced by connective tissue fibroblasts.

Question 186

Falciform ligament contains?

Answer 186

Ligamentum teres hepatis (derivative of fetal umbilical vein).

Question 187

Which GI ligament may be compressed between thumb and index finger placed in omental foramen to control bleeding?

Which GI ligament can lead to jaundice when an adenocarcinoma is centered near the pyloric sphincter on the lesser curvature?

Answer 187

1. Hepatoduodenal ligament - contains portal triad (proper hepatic artery, portal vein, common bile duct)
   * If liver bleeding does not cease when the portal traid is occluded, it’s likely that there has been injury to the IVC or hepatic veins.
2. Tumor can impinge on the omental foramen, which is formed partly by the hepatoduodenal ligament –> obstruction of the common bile duct leads to cholestasis and subsequently conjugated hyperbilirubinemia.

Question 188

Celiac trunk

Answer 188

1. Strong anastomoses exist between:

• Left and right gastroepieploics (supplying greater curvature).
• Left and right gastric arteries (lesser curvature).
• Occlusion of a single artery is tolerated. ***

2. Short gastric artery supplies fundus of the stomach & doesn’t anastomose: greastest risk of ischemiae when celiac trunk is occluded.
3. Anterior superior pancreaticoduodenal/posterior superior pancreaticoduodenal innervate pancreas.
   * Inferior pancreaticoduodenal supplied by SMA.
4. Posterior duodenal ulcers penetrate gastroduodenal artery.

Question 189

How is esophageal squamous cell carcinoma different from adenocarcinoma?

Answer 189

Squmous cell carcinoma

• Upper 2/3, more common world-wide
• Alcohol, smoking, N-nitroso-containing foods.
• Keratin pearls + intercellular bridges

Adenocarcinoma

• Lower 1/3 (distal), more common in America
• GERD, Barrett esophagus (intestinal-type columnar cells), obesity, smoking.

Question 190

Derivatives of first pharyngeal arch

• Maxilla
• Zygoma
• Mandible
• Incus, malleus
• Muscles of mastication (eg, masseter, temporalis)
• Trigeminal Nerve.

Answer 190

Derivatives of second pharyngeal arch:

• Styloid process of temporal bone.
• Lesser horn of the hyoid.
• Stapes.
• Muscles of facial expression
• CN VII.

Question 191

Presbycusis

Answer 191

The most common cause of sensorineural hearing loss in the elderly and manifests with gradually worsening high-frequency hearing loss. Degeneration of the proximal hairs cells of the organ of corti.

Question 192

An 11-year-old boy with intellectual disability is noted to have unusually long face, large jaw, large everted ears, and macroorchidism. Dx?

Answer 192

Fragile X syndrome, an X-linked defect affecting the methylation and expression of the FMR1 gene (CGG).

• A small gap near the tip of the long arm of the X chromosome.
• Expansion of trinculeotide repeats (CGG) in the FMR1 gene.
• Developmental delay (speech and motor) is common in infancy, but neuropsychiatric features often present in childhood (eg, anxiety, ADHD, ASD).

Question 193

A patient presents with daytime sleepiness, cataplexy, sleep paralysis, and (hypnagogic/hypnopompic) hallucinations. Dx & Tx?

Answer 193

Narcolepsy; orexin deficiency.

• treat with stimulant such as modafinil.
• Avoid suvorexant (orexin receptor antagonist).

Question 194

Clostridia: Gram (+) spore-forming obligate anaerobic rods.

TOXINS

Answer 194

1. C. tetani

• Wound –> Motor Neurons –> Spinal cord.
• Exotoxin blocks glycine and GABA release from Renshaw cells in the spinal cord, preventing the inhibitory signal from reach motor neurons downstream.
• Risus sardonicus/opisthotonus.

2. C. botulinum

• Infants: Preformed toxins in honey
• Can used to treat focal dystonias, achalasia and spasms.

3. C. perfringens

• Loss of cell membrane integrity.
• alpha-toxin lecithinase (watery diarrhea).
• Clostridial myonecrosis (gas gangrene).

4. C. difficile

• Pseudomembranous colitis.
• Toxin A: enterotoxin (diarrhea); Toxin B: cytotoxin that disrupts cytoskeleton via actin depolymerization.
• Secondary to antibiotic/PPI use, espeically clindamycin or ampicillin ; disrupts intestinal microbiome.
• Tx: Fidaxomicin: macrocyclic antibiotic that inhibits the sigma subunit of RNAP + metronidazole + vancomycin.

Question 195

A patient, after taking antipsychotic medication (typical - haloperidol, chlorpromazine, fluphenazine), presents with altered mental health status, fever, consciousness shifts, autonomic instability (HTN, tachycardia, tachypnea), and muscle rigidity.

Answer 195

NMS.

Tx: dantrolene or dopamine agonists (bromocriptine)

Question 196

Signs & symptoms of ICP ? Tx?Copyright (c) UWorld, Please do not save, print, cut, copy or paste anything while a test is active.

Answer 196

• Coma, bradycardia (respiratory depression), HTN, and papilledema.
• • The immediate Tx is intubation with mechanical ventilation (to rid of CO₂, which is a very potent vasoconstrictor that can increase ICP), elevating the head of the bed to 30 degree, and using osmotic diuretics such as mannitol.

Question 197

Ascending: Exophytic mass, IDA, weight loss

Descending: INfiltrating mass, partial obstruction, oclikcy pian, hematochezia.

Answer 197

1. Iron deficiency anemia (fatigue, pallor) and (occult) rectal bleeding, accompanied by weight loss, (esp. involving ascending colon) in males (espeically >50) and postmenopausal females

• “Colon cancer until proven otherwise”

2. Adenomatous polyps:

• Chromosomal instability pathway with mutations in AK53 mutation.
• Tubular histology has less maligant potential than villous.

3. CEA tumor marker: good for monitoring recurrence, should not be used for screening.

4. Chromosomal instability pathway

• Loss of APC gene: colon at risk
• Loss of KRAS gene: Unregulated intracellular signaling leading to adenoma
• Loss of p53: adenoma–> carcinoma.

5. Overexpression of COX-2 has been linked to colorectal cancer; NSAIDs may be chemopreventive.

Question 198

• Lynch syndrome (HNPCC)
  
  • Increased risk of colorectal, endometrial, and ovarian cancer.
  • eg) microstatellite instability.
• FAP
  
  • An autosomal dominant mutation in the APC tumor suppressor gene.
  • Adenomatous colonic polyps starting in the puberty.
  • Derivatives: Gardner (Fibromatosis + Osteomas) & Turcot (CNS tumors).

Answer 198

• Peutz-Jeghers: Hamartomatous polyps+ hyperpigmented mouth, lips, hands, genitalia.
• Juvenile polyposis syndrome: in children.

Question 199

• Microcephaly/holoprosencephaly.
• Microphthalmia.
• Cleft lip/palate.
• Cutis aplasia (focal skin defect of the scalp).
• Polydactylyl.
• Congenital heart diseae.
• Omphalocele.

Answer 199

Trisomy 13.

Question 200

Lewy body dementia

Answer 200

• Deficits in executive and visuospatial funciton, have trouble driving, get lost frequently, and have poor on-the-job performance.
• In addition to dementia, patients must have two of the three following symptoms: cognitive fluctuations, visual hallucinations, and parkinsonism with frequent falling.

Question 201

A 76-year-old woman with a long-standing history of HTN and vascular claudication was found deceased in her home. An autopsy determined the cause of death to be an acute M.I. Additionally, multiple cystic lesions (5 to 6-mm cavities in the deep stuctures of her brain filled with clear fluid), surrounded by hemosiderin-laden macrophages, were discovered in the basal ganglia.

Answer 201

Lacunar infarctions:

• Small vessel disease and are usually associated with long-standing HTN, DM, and atherosclerosis.
• Most commonly affect the small penetrating arterioles that supply the deep brain structures (eg, basal ganglia, pons) and subcortical white matter (eg, internal capsule, corona radiata).
• Lipohyalinosis, microatheroma formation, and hypertensive arteriolar sclerosis.
• In the acute setting, CT imaging may not reveal the expected hypodensity of ischemic stroke due to the small infarct size.

Question 202

A patient presents with an eye appearing in a “down-and-out” position, mydriasis (sphincter pupillae), diplopia, and partial ptosis (levator palpebrae superioris). Which CN would be affected?

Answer 202

CN III.

Question 203

The vitamin deficiency seen in patient with Wernicke-Korsakoff serves as a cofactor for?

Answer 203

1. B₁ is a required cofactor for several dehydrogenase enzyme:

• a-ketoglutarate dehydrogenase
• pyruvate dehydrogenase
• transketolase.
• branched-chain ketoacid dehydrogenase

2. Deficiency results in: beriberi (cardiac and neurologic complications) and/or Wernicke-Korsakfoff syndrome.

• Dry: Symmetrical peripheral neuropathy
• Wet: Addition of cardiac involvement (cardiomyopathy, high-output CHF, peripheral edema, and tachycardia).

Question 204

A patient presents with upper extremity weakness, face weakness (sparing the forehead), along with a gaze deviating toward the contralateral side. Dx?

Answer 204

Infarcts in the MCA.

• MCA also supplies Broca’s area (left inferior frontal gyrus)
• Wernicke’s area (left superior temporal gyrus): aphasia.
  
  • Since this region of the temporal lobe also contains fibers of the visual radiations traveling to the primary visual cortex, patients can also present with right upper quadrantanopia.

Question 205

• Adolescence.
• Neuropathic pain.
• Hypohidrosis.
• Angiokeratomas: dark red, non-blanching macules and papules that clasically occur in clusters over the buttocks, groin, and umbilicus.
• Telangiectasias.

Answer 205

Fabry disease:

• Accumulation of ceramide trihexoside due to a-galactosidase A deficiency.
• Renal, cardiac, or cerebrovascular disease complications.

Question 206

• More prevalent in Jew.
• Hepatosplenomegaly.
• Pancytopenia.
• Avascular necrosis of femur (due to insufficiency of medial circumflex femoral artery).

Answer 206

Gaucher disease, deficiency in B-glucocerebrosidase leads to glucocerebroside accumulation in the brain, liver, spleen, and bone marrow.

Peripheral blood smear would show Gaucher cells (lipid-laden macrophages resembling crumpled tissue paper).

Question 207

Ectoderm derivatives ?

Answer 207

Surface Ectoderm

• Epidermis
• Lens of eye; oral cavity; sensory organs of ear; olfactory epithelium
• Adenohypophysis (Rathke pouch)
• Parotid, sweat, mammary glands

Neural tube/Neuroectoderm - CNS

• Brain: Neurohypophysis; CNS neurons; oligodendrocytes; astrocytes (BBB); ependymal cells; pineal gland
• Spinal cord.

Question 208

Dizygotic twins:

• Always have 2 chorions and 2 amnions.
• A male and a female.

Answer 208

In monozygotic twins, the timing of cleavage determines chorionicity and amnionicity:

Cleavage between 0-4 days (2-cell stage to morula): Dichorionic/Diamniotic

Cleavage between 4-8 days (morula to blastocyst): Monochorionic/Diamniotic

Cleavage after 8-12days: Monochorionic/Monoamniotic or Conjoined twins (Seam twins).

Question 209

A homeless, alcoholic patient presents with confusion, ophthalmoplegia, and ataxia. What’s the most feared complication?

Answer 209

Wernicke encephalopathy can progress to Korasakoff syndrome: fabrication of stories to fill memory gaps. Anterograde amnesia is irreversible.

Lesions are located in the mammillary bodies.

AST > ALT.

Tx: Thiamine (B1) before glucose infusion.

Question 210

The brachial artery, median nerve, and radial nerve all run anterior to the elbow with the brachial artery and median nerve running together medially and the radial nerve running laterally.

Answer 210

Ulnar nerve runs immediatley posterior to the medial epicondyle.

Question 211

A 45-year-old woman is brought to the ER after an accident. She does not use tobacco or illicit drugs but admits to drinking 6-8 beers daily for the last several years. Her BAC indicates she’s intoxiated. Which of the following symptoms or signs is most likely to appear earliest during patient’s hospitalization?

Answer 211

Fine hand tremor.

Tx: Benzodiazepines (e.g., chlordiazepoxide).

Question 212

Increased number of polyglutamine repeats neart the amino terminal of the huntingtin protein.

Answer 212

1. Symptoms manifest between ages 20 ~ 50: Chorea, athetosis, aggression, depression, dementia.
2. Anticipation results from expansion of CAG repeats

• Deacetylation of histone leading to transcriptional repression.
• Caudate loses ACh and GABA.

3. Autosomal dominant.

Question 213

A HIV patient presents with areflexia, spasticity, lower extremity pain & weakness, urinary retention, and numbness. What other symptoms would you see?

Answer 213

CMV:

• Immunocompetent: Heterophile antibody-negative mononucleosis-like syndrome (fever, fatigue, splenomegaly, atypical lymphocytosis)
• Immunocompromised:
  
  • Retinitis can cause retinal detachment.
  • Esophagitis: Linear, shallow ulceration (in the lower esophagus).
• Enlarged cells with basophilic or eosinophilic intranuclear inclusion bodies

TRANSPLANT RECIPIENTS & IMMUNOCOMPROMISED (HIV) PATIENTS.

Question 214

Treatment for CMV

Answer 214

1. Gancyclovir:

• MOA: Activated by phosphorylation by viral protein kinases and acts as an analogue to dGTP, competitively inhibiting the incorporation of dGTP into replicating viral DNA.
• ADR: myelosuppression & nephrotoxicity.

2. Foscarnet, which selectively inhibits the pyrophosphate binding site on DNA polymerase without viral modification.

• For gancyclovir-resistant CMV.
• ADRs: Electrolyte disturbances including hypocalemiae, hypomagnesiae, hypokalemiae, hypophosphatemiae.

Question 215

A 10-year-old boy presents with:

• Progressive intellectual disability.
• marfanoid habitus.
• Ectopia lentis: displaced downward.

Answer 215

Homocystinuria, with elevated homocysteine levels in blood and urine.

• Complication: Cardiovascular effects (thrombosis and atheroscleorsis –> CAD, stroke and MI).
• Cystathionine synthase: Cysteine becomes essential and increased methionine causes toxicity.
  
  • B6 supplement.

Question 216

Marfan syndrome.

Answer 216

Mutations in the fibrillin gene:

• A major component of microfibrils that form a sheath around elastic fibers.

Marfan syndrome has similar presenstations to homocystinuria, but with an upward lens dislocation and without intellectual disability.

• Aortic root dilation, dissection, and rupture.

Question 217

Myotonic Dystrophy

Answer 217

1. CTG trinucleotide extension: autosomal dominant.

• Myotonia (difficulty relaxing muscles & losing a grip).
• Muscle wasting (muscular dystrophy)
• Cataracts/testicular atrophy/frontal balding/arrhythmia.

2. Anticipation: Offspring of those with the disease allele can acquire more copies of the mutated trinucleotide, thus exhibiting symptoms at earlier ages.

Question 218

A patient presents with jaw fatigue and muscle weakness, particularly late in the day and along with the physical exam finding of ptosis. CXR is shown below. Dx & Tx?

Answer 218

Myasthenia gravis: Neuromuscular-junction (NMJ) disorder caused by antibodies that block the nicotinic acetylcholine receptors (type II hypersensitivity).

• Reduced post-synaptic motor end-plate potential.
• Ocular & bulbar muscle weakness.
• Thymoma present (mediastinal mass).
• Edrophonium (rapid acting AChEI) can be used to make a diagnosis.
• Tx: pyridostigmine.
  
  • Treat overdose with scopolamine/hyoscyamine.

Question 219

Treatment for ischemic stroke?

Answer 219

Thrombolytic therapy (alteplase, streptokinase) if <5 hours.

• Antidote: Aminocaproic acid.

Other choices inlcude antiplatelet drugs (e.g., aspirin) and anticoagulants (e.g., warfarin).

Question 220

What’s the long-term consequence of measles/rubeola virus?

Answer 220

Subacute sclerosing panencephalitis (SSPE): personality changes, lethargy, difficulty in school, odd behaviour, dementia, severe myoclonic jerking.

Often a history of primary measels infections at an early age (2) followed by a latent interval of 6-8 years:

• Maculopapular rash head-down (Cephalocaudal & centrifugal).
• Cough.
• Coryza.
• Conjunctivitis.
• Koplik spots.
• Warthin-Finkeldey cells in respiratory secretions.
• Complicated by vit. A deficiency.
• Live, attenuated MMR vaccine.

Question 221

A 43-year-old man with PMH of HIV presents with vision problems, speech, memory, and coordination. CD4 cell count is <24 cells/mL. A 3D FLAIR MRI revealed (multiple) nonenhancing areas of demyelination.

Answer 221

JC virus causes progressive multifocal leukoencephalopathy:

• Occurs in HIV patients with CD4 < 200/mm³
• Multiple areas of demyelination throughout the white matter of the CNS.
• Very rapid progression to death: initial findings include deficits of speech, memory, and coordination.
• ↑ Risk with natalizumab, rituximab.

Question 222

A strict vegan presents with fatigue, tingling in her hands/feet, depressed mood and memory issues, unsteady gait, conjunctival pallor, shiny/enlarged tongue. Dx?

Answer 222

1. Vitamin B₁₂ deficiency, which affects spinocerebellar tracts, lateral corticospinal tracts, and dorsal columns (SCD).
2. Other causes of vitamin B₁₂ deficiency:

• IBD (e.g., Crohn disease most commonly manifests as a terminal ileitis, and the terminal ileum is the site of IF absorption).
• H. pylori.
• D. latum infection.

Question 223

A 2-year-old boy is brought to the ED by an ambulance after an episode of seizure-like activity. His mother says he developed a fever of 104°F earlier that afternoon. A few hours later, he had an episode of “whole-body” shaking that lasted 4 min, but quickly recovered. Dx & Tx?

Answer 223

Simple febrile seizure

• 6 months - 5 years.
• Generalized clonic or generalized tonic-clonic
• A single episode lasting < 15min
• Lack of underlying neurologic disease; usually recovers spontaneously.
• Most caused by HHV-6 (roseola infantum) or influenzae.
  
  • High fever for 3-5 days followed by an erythematous maculopapular rash.

Question 224

• PMH of ADPKD.
• Presents with sudden onset of severe headache and confusion.
• Blood in subarachnoid space.

Answer 224

Subarachnoid hemorrhage.

• most likely due to rupture of an aneurysm (such as a berry/ saccular aneurysm) or AV malformation.
• Vasospasm can ensue –> Tx with nimodipine (CCB).

Question 225

Which nerve can be blocked to relieve woman’s perineal pain?

Answer 225

Pudendal nerve block is performed injecting an anesthetic intravaginally, medially to ischial spine, through sacrospinous ligament.

S2-S4:

• External urethral and anal sphincters: fecal incontinence, external urethral sphincter paralysis.
• Sensory innervation to external genitalia/anal: decreased sensations.

Question 226

Which drug, if used in combination with SSRIs (sertraline/citalopram/fluoxetine) or TCAs (amitryptyline) can cause serotonin syndrome ?

Answer 226

1. MAOIs: Tranylcypromine, phenelzine, isocarboxazid, selegiline.

• MAO: Serotonin, NE, Dopamine.
• Treatment-resistant & atypical depression (eg, mood reactivity).
• LINEZOLID ***: an antibiotic used to treat Gram-positive infections, particularly VRE and MRSA; has MAOI activity.

2. ADRs: Serotonin syndrome, HTN crisis.
3. May take up to 2 weeks following discontinuation of the drug before the enzyme is resynthesized to levels adequate for normal monoamine degradation (/oxdiation).

Question 227

Serotonin Syndrome

Answer 227

• Neuromuscular hyperActivity: clonus, hyperreflexia, tremor, seizure.
• Autonomic stimulation: hyperthermia, hypertension, tachycardia, diaphoresis, diarrhea.
• Agitation & delirious.
• Tx: cyproheptadine.
• Serotonin derived from tryptophan.
• Utilizies tryptophan hydroxylase (eg, tetrahydrobiopterin)
• Concentrated in raphe nuclei.

Question 228

An anorexic/bulimic patient presents with seizure after taking an antidepressant.

Answer 228

Bupropion; inhibits reuptake of NE and dopamine.

• 1st-line Tx for major depressive disorder that does not cause sexual dysfunction.

Question 229

Vitamin B₃ deficiency can cause?

Answer 229

1. Vitamin B₃:

• Pellagra: Diarrhea, Dermatitis, Dementia (+beefy glossitis)
• May also be seen in Hartnup disease, carcinoid syndrome, and vitamin B₆ deficiency.
• An essential component of the coenzyme NAD and NADP.
  
  • Serves as a cofactor for isocitrate dehydrogenase and malate dehydrogenase.

2. Hartnup:

• Deficiency of neutral amino acid (e.g., Trp) transporters in proximal renal tubular cells and on enterocytes.
• Neutral aminoaciduria.
• Tryptophan for conversion to niacin –> pellagra-like symptoms.

Question 230

Cerebellar lesion would manifest as?

Answer 230

Ipsilateral deficits, including loss of coordination (ataxia), hypotonia, intention tremor, and instability (patient feels as if he/she is going to fall toward the side of the lesion).

Question 231

Ca²⁺-Calmodulin will act ?

Answer 231

Activates MLCK, which in turn phosphorylates myosin light chains. Once phosphorylated, MLCs facilitate cross-bridge formation and smooth muscle contraction.

Question 232

A patient presents with recurrent/episodic episodes of vertigo, along with low-frequency sensorineural hearing loss in the right ear (Weber localizes to unaffected ear), and tinnitus.

Answer 232

Meniere disease:

• ↑ Volume & Pressure of endolymph.

Question 233

What are major lymphatic drainage for reproductive structures?

Answer 233

1. Ovaries/tests –> para-aortic lymph nodes.
2. Descending & sigmoid colon & Rectum proximal to the anal dentate line (pararectal) –> inferior mesenteric and internal iliac lymph nodes.

3. Below umbilicus: Genitalia (penis, scrotum, perineum, vulva), buttocks, anus below the dentate line (eg, orifice of the anal canal), abdominal wall –> Superficial inguinal lymph nodes.

4. Deep inguinal nodes: receive lymph drainage from glans penis & skin of the posterior calf (popliteal lymph nodes).

Question 234

Following a total abdominal hysterectomy, a patient presents with a fever and right-sided back pain. She has been able to urinate without any difficulty. Injury to which of the following structures is the most likely explanation for this patient’s post-op symptoms?

Answer 234

1. Ureter at risk of injury during ligation of uterine vessels in hysterectomy (cardinal ligament)
2. Unintentional ureteral ligation causes obstruction with hydronephrosis and flank pain due to distension of the ureter and renal pelvis.
   * Since the second ureter is uninjured, patients are able to void normally.

Question 235

Meiosis I is arrested in prophase I until ovulation.

Meiosis II is arrested in metaphase II until fertilization.

Answer 235

Mittelschmerz: transient mid-cycle ovulatory pain; classically associated with peritoneal irritation (follicular swelling/rupture, fallopian tube contraction). can mimic appendictis.

Question 236

1. hCG

• Maintains corpuse luteum (and thus progesterone) for first 8-10 weeks of pregnancy. After 8-10 weeks, placenta synthesizes its own estriol and progesterone and corpus luteum degenerates.
• ↑: Multiple gestations & Hydatidiform moles & Choriocarcinomas & Down syndrome.
• ↓: Ectopic/failing pregnancy & Edward syndrome & Patau syndrome.

Answer 236

2. hPL
   * Stimulates insulin production; increased insulin resistance due to shunting carbohydrate metabolism toward supplying glucose/amino acids to fetus.

Question 237

A 50 y.o. female presents with hot flashes, dry vagina, osteoporois, CAD, and sleep disturbances. Which lab finding would support your diagnosis?

Answer 237

Menopause:

• ↑↑ FSH (loss of negative feedback on FSH due to ↓ estrogen); ↑↑ GnRH.
• Mean age in the US: ~ 51 y.o.
• Vertebral compression fractures are a common complication of postmenopausal osteoporosis due to loss of trabecular bone and can occur with low-intensity trauma.

Question 238

• Amenorrhea at age <40
• (UP) FSH
• (DOWN) Estrogen.

Answer 238

• Premature follicular atresia (eg, apoptosis).

Question 239

1. Placental aromatase deficiency

• Inability to synthesize estrogens from androgens.
  
  • ↑ Serum testosterone and androstenedione.
• High androgen and low estrogen levels in the female fetus.
  
  • Normal internal genitalia + ambiguous external genitalia.
• Maternal virilization (eg, hirsutism) commonly occurs during prengnacy due to transfer of excess androgens into the maternal ciruclation.

Answer 239

2. Mullerian aplasia

• Variable uterine development + upper vagina (short vagina)
• Primary amenorrhea
• Normal ovaries, which secret estrogen –> regular development of secondary sexual characteristics.

Question 240

Complete mole vs. partial mole:

Answer 240

1. Complete mole:

• 46, XX > 46, XY (paternal DNA only).
• First-trimester vaginal bleeding and an enlarged uterine size out of proportion to gestational age.
• No fetal parts; ↑↑↑ hCG.
• Diffuse trophoblastic proliferation & edematous chorionic villi: “Honeycombed” uterus or “clusters of grapes”, “snowstorm” on U/S.
• ↑ risk of malignancy (eg, choriocarcinoma).

2. Partial mole:

• 69, XXX; 69, XXY; 69, XYY (paternal & maternal DNA).
• Yes fetal part (focal trophoblastic proliferation); ↑ hCG.
• Presents in early pregnancy with vaginal bleeding and no fetal cardiac activity.
• <5% risk of malignancy.

Question 241

Compare & contrast placental abruption vs. placenta accreta/increta/percreta vs. placenta previa.

Answer 241

Placental abruption:

• Abrupt, painful bleeding in 3rd trimester (dark red blood); possible DIC, maternal shock, fetal distress.
• Risk factors: trauma, smoking, hypertension, preeclampsia, cocaine abuse.

Placental accreta: attaches to myometrium without penetration.

• Risk factor: prior surgery (e.g., C-section)
• No separation of placenta after delivery –> postpartum bleeding (Tx: oxytocin).

Placental increta: placenta penetrates into myometrium

Placental percreta: invades entire uterine wall; can result in placental attachment to rectum or bladder.

Placenta previa:

• Attachment of placenta to lower uterine segment or internal cervical os.
• Prior C-section;associated with painless 3rd bleeding (bright red blood).

Question 242

A female patient presents with sudden lower abdominal pain in RLQ region and vaginal bleeding. Her LMP was 6 weeks ago. Past surgical history is significant for C-sections and permanent sterilization via a bilateral tubal ligation. A urine pregnancy test is positive, and an ultrasound shows a 2-cm mass in teh left adnex adjacnet ot the ovary and a thickeend endometrial stripe. Dx?

Answer 242

Ectopic pregnancy:

1. A uterine curettage would reveal decidualized endometrium only: dilated, coiled endometrial glands and edematous stroma; embryonic and trophoblastic tissue will be absent.
2. Risk f(x):

• Prior ectopic pregnancy
• History of infertility
• PID (e.g., Neisseriae & Chlamydia trachomatis)
• Ruptured appendix
• Prior tubal surgery (e.g., ligation).

Question 243

A 4-year-old girl presents with clear, grape-like, polypoid mass emerging from her vagina. Dx?

Answer 243

Embryonal rhabdomyosarcoma variant; sarcoma botryoides.

• Malignant tumor of skeletal muscle.
• Rhabdomybolast is the characteristic cell; desmin positive.

Question 244

• Dysmenorrhea *** (vary with menstrual cycle).
• Adhesions may interfere with ovulation and fallopian tube function, resulting in infertility.
• Implants and adhesions involving the uterosacral ligament can result in a fixed, retroverted uterus.
• Infiltration of posterior cul-de-sac (eg, Pouch of Douglas) can result in painful intercourse and tenderness with palpation of the posterior vaginal fornix.
• “Chocolate cyst” - endometrioma filled with dark, reddish-brown blood.
• Most often affects ovary (lined by simple cuboidal epithelium)

Answer 244

Ectopic growth of endometrial glands and stroma in the peritoneum and pelvic organs

Question 245

Mature cystic teratoma vs immature cystic teratoma: ovarian neoplasm.

Answer 245

1. Germ cell tumor, most common ovarian tumor in female 10-30 years old.

• Cystic mass containing elements from all 3 germ layers (teeth, hair follicles, sebum, skin).
• Can present with pain secondary to ovarian enlargement or torsion.
• A monodermal form with thyroid tissue (struma ovarii) uncommonly present w/ hyperthyroidism.

2. Immature teratoma: Aggressive; typically represented by immature/embryonic-like neural tissue.

Question 246

Dysgerminoma vs. yolk sac tumor: ovarian germ-cell neoplasm

Answer 246

1. Dysgerminoma

• Most common in adolescents = equivalent to male seminoma.
• Sheets of uniform “fried egg” cells.
• ↑↑↑hCG, LDH.

2. Yolk sac tumor

• Aggressive, in ovaries or testes and sacrococcygeal area in young children; most common in male infants.
• 50% have Schiller-Duval bodies.
• ↑↑↑ AFP (also seen in hepatocellular carcinoma).

Question 247

Granulosa cell tumor

Answer 247

• Most common malignant stromal tumor.
• Predominantely women in 50s.
• Often produces estrogen and/or progesterone and presents with endometrial hyperplasia (post-menopausal bleeding, sexual precocity, breast tenderness).
• Histogloy shows Call-Exner bodies (cuboidal granulosa cells in a rosette pattern with coffee bean nuclei).
• Yellow theca cells with lipid.

Question 248

A patient who worked at textile mill presents with a 1-month history of “red pee”.

Answer 248

MRI is remarkable for dark thickening of his bladder, which given his history of hematuria, is concerning for transitional cell carcinoma.

• Painless gross hematuria, weight loss, night sweats
• Associated with: Phenacetin, smoking, aniline dyes, and cyclophosphamide.
• Tumor stage is the most important factor determining prognosis and depends on the degree of invasion into the bladder wall and adjacent tissues.

Question 249

Median nerve courses between the humeral and ulnar heads of the pronator teres muscles and then runs between the flexor digitorum superficialis and the flexor digitorum profundus muscles before crossing the wrist within the carpal tunnel.

Answer 249

• First and second lumbricals: flex the MCP joints and extend the interphalangeal joint.
• Flexor digitorum supeficialis: flexes the MCP and PIP joints.
• Lateral half of the flexor digitorum profundus: flexes DIP
• Flexor pollicis longus tendon: thumb abduction & opposition.
• All contained within transverse carpal ligament (flexor retinaculum) on the volar aspect.
  
  • Carpal tunnel.

Question 250

• Recurrent episodes of UTI.

Answer 250

As the kidneys rise from the pelvis, they encounter the inferior mesenteric artery

Question 251

A 2-year-old girl is brought to the clinic because she has recently developed muscle weakness. A peripheral nerve biopsy reveals histologic evidence of demyelination and macrophages with prominent reddish-pink vacuoles in the cytoplasm after staining with toluidine blue.

Answer 251

Metachromatic leukodystrophy:

• Central and peripheral demyelination with ataxia, dementia
• Arylsulfatase A deficiency –> Accumulation of cerebroside sulfate.

Question 252

Frontal lobe disinhibiton would manifest as?

Answer 252

1. Left-sided lesions: apathy, depression
2. Right-sided lesions: disinhibited behaviour.
3. Reappearance of primitive reflex.

Question 253

Leber hereditary optic neuropathy

Answer 253

A mitochondrial mutation (mother –> offspring) that causes degeneration of the optic nerve with rapid loss of central vision, leading to a central scotoma.

• Males > females, in 30’s

Question 254

What do different regions of hypothalamus regulate ?

Answer 254

1. Lateral area: Hunger; stimulated by ghrelin & inhibited by leptin.
2. Ventromedial area: Satiety; stimulated by leptin.
3. Anterior hypothalamus: cooling, parasympathetic
4. Posterior hypothalamus: heating, sympathetic.
5. Paraventricular & supraoptic: ADH & oxytocin.
6. Suprachiasmatic: Circadian rhythm regulation & pineal gland function.

Question 255

During what stage of sleep would you see sleep spindles and K complexes?

Answer 255

Stage N2.

BATS DRINK BLOOD

Question 256

New-onset seizures in an HIV positive ptient with a CD4 count < 100 cells/uL is highly suggestive of?

Answer 256

Toxoplasmosis: obligate intracellular protozoan.

• Multiple ring-enhancing central nervous system, especially in immunocompromised (HIV) patients.
• Other manifestations are chorioretinits, characterized by eye pain and decreased visual acuity, hydrocephalus, intracranial calcifications, and microcephaly (eg, in-utero infection).
• Extensive pet exposure (cat feces) is not always essential.
• Tx: pyrimethamine and sulfadiazine.

Question 257

Epidural hematoma

• Middle meningeal artery (branch of maxillary artery) lacerated by a fractured temporal lobe (pterion).
• Biconvex disc on CT.
• Lucid interval followed by a rapid deteroriation.

Answer 257

Subdural hematoma

• Bridging veins (from the cerebrum to the dural sinuses) are more vulnerable in the elderly as a result of the natural atrophy of the aged brain and their subsequent stretching.
• Trauma or atrophy.
• Shaken baby syndrome (+bilateral retina hemorrhages).
• Crescent-shaped CT on scanning.
• Slow, progressive deterioration.

Question 258

A 12-year-old boy has been seizeing for 14 minutes. He’s alternatively contracting and jerking his extremities in a rapid manner. Dx & Tx?

Answer 258

Status epilepticus

• > 5 min of continuous activity of multiple seizures without an intervening return to baseline.
• 2 or more discrete seizures between which there’s incomplete recovery of consciousness.

Tx:

• Benzodiazepine to rapidly control and abort the seizure.
• Followed by IV phenytoin to prevent recurrence.
  
  • Na+ blocker.
  • ADR: gingival hyperplasia; megaloblastic anemia; SLE; teratogen

Question 259

Type 1 hypersensitivity:

Answer 259

IgE-mediated basophils and mast cells release vasoactive mediators (histamine + tryptase)

• Allergies; atopic disease; anaphylaxis (following food & medications & insect stings).
• Mast cells: bind the Fc portion of IgE to membrane; IgE crosslinking by antigen leads to degranulation.

Question 260

A 12-year-old girl presents with amnesia and bizzare behaviour over the past 2 days. MRI of the brain is shown. Dx?

Answer 260

1. HSV-1 encephalitis; CT or MRI of the brain typically demonstrates focal pathology in the temporal lobe (can cause seizures)
2. Other findings may include:

• Gingivostomatitis (painful vesicles covering the lips & hard palate & gingivia).
• Keratoconjunctivitis
• Latent in trigeminal ganglia (sensory neurons) —> Reactivation leads to herpes labialis (eg, cold sores).

3. Blood smear: Multinucleated giant cells with intranuclear inclusions (eg, Tzanck smear).

Question 261

Temporal lobe lesion would manifest as ?

Answer 261

• Memory disturbances (eg, hippocampus)
• Speech (eg, Wernicke area in dominant hemisphere)
• Vision (eg, Meyer loop)
• Hearing
• Bilateral damage to the amygdala results in Kluver-Bucy syndrome (eg, hyperphagia, hyperorality, hypersexuality).

Question 262

The most common cause of childhood nephrotic syndrome (following an URI)

Answer 262

Mimimal Change Disease

• Peripheral and periorbital edema
• Massive proteinuria —> Hypoalbuminemia
• Hyperlipidemia.
• Involvement of (possible) T lymphocytes?
  
  • Effacement of foot processes of the podocytes on electron microscopy: Loss of negative charge leads to selective loss of albumin in the urine.
  • Responds well to steroids

Question 263

• Male children, aged 3 ~ 11.
• Palpable rash on buttocks & legs.
• Abdominal pain.
• Arthralgia.
• Hematuria (renal disease due to IgA nephropathy).

Answer 263

• Occurs a few days following infection (eg, URI).
• Circulating IgA-antigen immune complexes (Type III hypersenstivity).
• Mesangial hypercellularity on LM.

Question 264

A mutation in B-tubulin will cause resistance to which anti cancer medications?

Answer 264

Both are M-phase specific.

Paclitaxel:

• Prevents microtubule disassembly.
• First-line therapy for metastatic ovarian/breast carcinoma.

Vincristine & vinblastine:

• Prevents microtubule assembly (+ colchicine, griseofulvin).
• May be useful for Hodgkin lymphoma (vinblastine).
• ADR: peripheral neuropathy.

Question 265

A patient who develops heparin-induced thrombocytopeniae is at risk of ?

Heparin:

• Binds to antithrombin & inhibits Factor Xa and IIa (eg, thrombin).

Answer 265

Heparin-induced thrombocytopeniae is an immunologic reaction to heparin, producing antibodies that cross-react with PF4, leading to platelet activation and clumping (thrombosis).

• Bivalirudin directly binds thrombin and inhibits its action. It is used to treat PE and DVT and is used instead of heparin for anticoagulation in patients with HIT.
• (Argatroban, dabigatran).

Question 266

A patient who started on adjuvant chemotherapy for germ cell tumor presents with following CXR.

Answer 266

Bleomycin:

• Antineoplastic antibiotic that halts cell division by generating free radicals that cause single double-stranded DNA breaks.
• Use: Testicular cancer, Hodgkin lymphoma.
• ADRs: Pulmonary fibrosis (CT shows cystic degeneration of the posterior lung bases with interstitial thickening/fibrosis and cyst formation).

Question 267

A 3-day-old girl is brought into the ER by her mother after having seizure. The patient was born at home at 37 weeks’ gestation to a 28-year-old primigravia. The mother took prenatal vitamins throughout her pregnancy but did not receive prenatal care. Small areas of ecchymoses are noted on the lower extremities. A cranil U/S indicates blood in the right lateral ventricle.

PT; PTT increased; positive stool guaiac test result

Answer 267

Dx: Hemorrhagic disease of the newborn secondary to vitamin K deficiency.

• Increased bleeding: dried blood around the umbilicus; ecchymoses on the lower extremities; positive stool guaiac test result (GI bleeding); intraventricular hemorrhage from germinal matrix bleeding (causing seizure).
• Vitamin K: necessary for gamma-carboxylation of glutamic acid residues on clotting factors II, VII, IX, X, Protein C & S.

Misc: Antibiotics (esp. cephalosporins) can disrupt normal abdominal bacterial flora, significantly decreasing levels of vitamin K.

Question 268

Common statistical tests:

Answer 268

1. t-test: Compares the mean values of 2 different populations.
2. ANOVA: Compares the mean values of >3 different populations.
3. Chi-square test: Test categorical (yes vs no) data.
4. The Pearson correlation coefficiency: a single number representing the strength and direction of a linear relationship between 2 quantitiative variables.
5. Meta-analysis: an epidemologic method of analyzing pooled data from several studies, thereby increasing the statistical power beyond that of the individual studies.

Question 269

The patient presents with weakness, weight loss, and constitutional symptoms. Additionally, he has luekocytosis, anemia, thrombocytopeniae, and his cytogenetic analysis reveals a common translocation. Blood smear is shown. Dx?

Answer 269

CML; associated with Philadelphia chromosome, t(9;22), BCR-ABL

• Peripheral blood smear: leukocytes of myeloid origin at various stages of development: myeloblast, promyelocyte, myelocyte, metamyelocyte, and band forms
• Basophilia & Eosinophilia ***
• Can progress to ALL or AML (blast crisis)
  
  • AML is notorious for causing DIC.
• Very low leukocyte alkaline phosphatase.
• A part of myeloproliferative disease and presents with elevated white count and platelet count ***
• Tx: BCR-ABL tyrosine kinase inhibitors, imatinib.

Question 270

A fair-skinned 56-year-old farmer presents to the clinic with a scaling, indurated, ulcerated nodule just below his lower lip. Biopsy reveals sheets of neoplastic epidermal cells and keratin pearls.

Answer 270

Squamous cell carcinoma

• Lower lip
• Keratin pearls
• Risk factors: sun exposure; industrial carcinogens; old burn scars; arsenic; exposure to ionizing radiation
• Locally invasive, may spread to lymph nodes, and will metastasize (although rarely).
• Actinic keratoses: thick, scaly, or crusty skin and are sandpaper-like on palpation.

Question 271

A 67-year-old former landscaper is referred to the dermatologist for a lesion on his right forearm. The lesion is a flesh-colored pearly papule approximately 1.5 cm in diamater with a central telangiectasia. A biospy is shown. Dx?

Answer 271

Basal cell carcinoma:

• Pink or flesh-colored pearly papules found in sun-exposed areas
• Papules are locally invasive but virtually never metastasize.
• Palisading nuclei, or small fusiform cells with little cytoplasm and hyperchromic dense nuclei.

Question 272

• Elderly patients.
• Fatigability (anemiae).
• Constipation (hypercalcemiae).
• Bone pain (bone lysis).
• Elevated serum proteins (monoclonal proteins).
• Renal failure.

Answer 272

• Bone marrow suppressed due to the hyperproliferation of plasma (mature B) cells: pancytopeniae
• Punched-out lytic bone lesions release calcium.
  
  • Elevated serum calcium & reduced PTH —> Hypercalciuria.
  • Renal failure –> Reduced 1,25-dihydroxyvitamin D synthesis.
• Bence Jones proteinuria: Monoclonal free light chains (cast nephropathy).
• High peak in the gamma-globulin region serum protein electrophoresis usually represents an M protein consisting of an overproduced monoclonal immunoglobulin.
• Rouleaux formation.
• AL amyloid:“apple-green” birefringence with Congo red stain when viewed under polarized light.

Question 273

Hodgkin lymphoma

Answer 273

• “B” symptoms: profuse sweating, fevers, significant weight loss.
• Localized, single group of nodes; contiguous spread (vs. multiple, generalized lymph nodes found in Non-hodgkin): usually cervical adenopathy, but can also have lymphoma located in the mediastium or lung.
• Reed-sternberg cells: bi- or multilobed nuclei and prominent nucleoli; positive for CD15 and CD30.
• May be associated with EBV, enveloped dsDNA virus (herpesviridae) ***
  
  • Also cause nasopharyngeal carcinomae.

Question 274

The patient presents with a central lung mass and high levels of cortisol and ACTH, unaffected by high-dose dexamethasone or corticotropin-releasing hormone. Dx & Tx?

Answer 274

1. Paraneoplastic syndromes of small cell lung carcinoma

• ADH, leading to SIADH (–> hyponatremia–> seizures).
• Cushing syndrome
• Lambert-Eaton (antibodies against calcium channels).
• Neuro/endocrine
  
  • Stains for: neural cell adhesion molecule (NCAM), enolase, chromogranin, and synaptophysin.

2. Ketoconazole & mitotane can be used to mitigate the progression to centripetal obesity and Cushingoid appearance.

Question 275

A 60-year-old patient presents with seizure, headache, and visual field deficit. Histology reveals following images. Dx?

Answer 275

Meningioma:

• Most often occurs near surfaces of brain and in parasagittal region.
• Extra-axial (external to brain parenchyma) and may have a dural attachment.
  
  • May present with seizures or focal neurologic signs.
• Arachnoid cell origin.
• Spindle cells concentrically arranged in a whorled patten
• Psammoma bodies.

Question 276

A brain biopsy shows midline shift & tumor crossing the corpus callosum, forming a “butterfly glioma”.

Answer 276

Glioblastoma multiforme (grade IV astrocytoma) :

• Most common primary brain tumor in adults.
• Cerebral hemisphere.
• Astrocyte origin, GFAP (+)
• Pseudopalisading: Pleomorphic tumor cells and central areas of necrosis and hemorrhage.

Question 277

Leuprolide mechanism of action

Answer 277

Initially causes a transient increase in pituitary LH secretion, which leads to a rise in testosterone levels. However, continuous use of leuprolide suppresses LH release and leads to a decrease in testosterone production.

• Continuous infusion of GnRH: Decreases the synthesis of estrogens and androgens.
• Pulsatile can be used to treat anovulation.

Question 278

Chronic Lymphocytic Leukemiae:

Answer 278

1. Smudge cells in peripheral blood smear.
   * Crushed little lymphocytes (CD5, CD19, CD20, CD23 positive).
2. Causes autoimmune hemolytic anemia.

• “Warm”: IgG , “Cold”: IgM.
• Direct: Can detect autoantibodies directed against the patient’s own RBCs.
• Indrect: Can detect the presence of unbound antibodies in the patient’s serum, which can bind to RBCs from a normal, healthy donor.

Question 279

A patient presents with painful abdomen, red-colored urine, and psychological disturbances.

Answer 279

Acute Intermittent porphyria (AIP)

• Deficiency of porphobilinogen deaminase.
• 5 P’s: Painful abdomen & port wine-colored urine & polyneuropathy; psychological disturbances & precipitated by drugs (eg, phenobarbital), alcohol, starvation.
• Tx: Glucose & Heme can inhibit ALA synthase, reducing downstream effects ***

Question 280

Drugs of choice for Hep.C?

Answer 280

1. Interferon-alpha
2. Ribavirin:

• Inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase.
• Also used for RSV.

Question 281

A 25-year-old man presents to the ER due to abdominal pain and swelling. He denies having a bowel movement for the past week. An abdominal CT revealed a significant mass. Biopy reveals?

Answer 281

Burkitt lymphoma:

• Jaw lesions in endemic form in Africa; pelvis or abdomen in sporadic form.
• “Starry sky” - sheets of highly mitotic, basophilic lymphocytes surrouding clear zones of macrophages.
• 8:14 translocation (c-myc).
  
  • Transcription activator.
  • Ki-67 fraction approaching 100%
• Strong association with EBV, linear ds-DNA.

Question 282

• Recent-onset gait instability and gait ataxia
• Midline posterior fossa mass
• Sheets of primtive cells and many mitotic figures.
• Children.

Answer 282

Medulloblastoma:

• Commonly involves cerebellum, compress 4th ventricle, causing noncommunicating hydrocephalus.
• Homer-wright rosettes.
  *

Question 283

Despite the high (immature) WBC, patients with ALL often present with neutropeniae because the rapid proliferation of WBCs crowds out production of other cells and causes bone marrow failure.

Question 284

Langerhans cell histiocytosis

Answer 284

• Presents in children as lytic bone lesions (bone swelling & tenderness); skin rash; recurrent otitis media with a mass involving the mastoid bone.
• Macrophges are deficient; cells are functionally immature and do not effectively stimulate primary T cells.

Question 285

Brown-Sequard syndrome

Answer 285

• Ipsilateral loss of all sensation at level of lesion
• Ipsilateral LMN signs at level of lesion
• Ipsilateral UMN signs below level of lesion (due to corticospinal tract damage)
• Ipsilateral loss of proprioception, vibration, light touch, tactile sense below loss of lesion (DCML).
• Contralateral pain, temperature, and crude touch below level of lesion (due to spinothalamic tract damage).

Question 286

What does following blood smear show?

Answer 286

Lack of central pallor (↑ MCHC); hereditary spherocytosis due to spectrin deficiency.

• Infections can trigger hemolysis and lead to acute hemolytic crisis.
• Presents in infants/children with severe jaundice and splenomegaly (+splenomegaly since the spleen rapidly clears spherocytes).
• Complications: black bilirubin gallstones and cholecystitis.
• Osmotic fragility test (+) on acidified glycerol lysis test.
• Parvovirus B19 –> aplastic crisis.
• Tx: splenectomy.

Question 287

How does pernicious anemia present?

Answer 287

1. Production of autoantibodies against parietal cells that lead to atrophic gastritis and IF deficiency (B12)
2. Decreased secretion of hydrochloric acid causes an elevated intraluminal pH and stimulates gastrin secretion by G cells (gastrin hyperplasiae).

Question 288

DIC (Increased FDP, prolonged prothrombin/partial thromboplasin, thrombocytoepanie) + following blood smear is indicative of which hematologic condition?

Answer 288

AML

• DIC: Bruising/oozing form venipuncture sites (suggesting low Pt) associated with low fibrinogen levels and immature myeloid cells.
• Needle-shaped cytoplasmic inclusions known as Auer rods (fused lysosomal granules, MPO +).

M3 variant of AML: APML: t(15;17)

• Disruption of the nuclear retinoic acid receptor (RAR) that’s required for maturation of myeloblasts.
• Tx: all-trans retinoic acid; promotes the terminal differentiation of the immature malignant promyelocytes into mature granulocytes.

Question 289

Antidote for cyclophosphamide/ifosfamide-induced hemorrhagic cystitis?

Answer 289

Mesna: binds to acrolein to form an inert compound that is excreted, preventing toxic exposure to the bladder epithelium.

Question 290

Granulocyte CSF that can be used to promote bone marrow recovery (and therefore prevent infections) in patients receiving myelosuppressive chemotherapy.

Answer 290

Filgrastim.

• G-CSF is a glycoprotein growth factor that stimulates neutrophils to differentiate in the bone marrow. As such, G-CSF binds a transmembrane receptor to effect downstream genes.
• Stimulates granulocyte production in patients with neutropenia (may present w/ fever secondary to infection) , and acts by activating pluripotent hematopoetic stems cells (CD34+).

Question 291

HNPCC is caused by?

Answer 291

Autosomal dominant mutation of DNA mismatch repair genes with subsequent microsatellite instability.

Associated with endometrial, ovarian, and skin cancers (at relatively younger age ~40).

Question 292

A 6-year-old of Greek ancestry is admitted to the hospital because of dehydration secondary to crampy abdominal pain and bloody diarrhea. Laboratory test results are significant for ↓Hg/Hct, platelet count (thrombocytopeniae), ↑ creatinine. Peripheral blood smear would show?

Answer 292

Microthrombi in small blood vessels –> Erythrocytes passing through the damaged capillaries suffer shear injury & schistocytes –> Microangiopathic hemolytic anemiae.

HUS in this patient.

• Microangiopathic hemolytic anemia
• Thrombocytopeniae
• Kidney failure (↑ creatinine)

Question 293

A 28-year-old female presents with malar rash, multiple miscarriages, chronic anticoagulation, and a positive test for syphilis. Dx & laboratory values?

Answer 293

SLE with antiphospholipid syndrome, which can lead to anemia of chronic disease.

• Normal to ↑ ferritin
• ↓TIBC, total iron saturation.
• Normocytic (normal MCV) anemiae.

Hepcidin is an acute phase reactant synthesized in liver that prevents iron release from macrophages.

Question 294

Most common cause of inherited thrombophilia/hypercoagulability?

Answer 294

Factor V leiden, which causes resistance to deactivation of factor V by protein C. Uninhibited factor V activity leads to a hypercoagulable state, which predisposes to DVT and subsequent P.E.

• Marked fever, tachycardia, tachypnea, leukocytosis, elevated D-dimer level, pleuritic chest pain.
• Aggravated by OCP+ smoking
  *

Question 295

Warfarin-induced skin necrosis

Answer 295

Warfarin (tx for a-fib). works via inhibition of vitamin K epoxide reductase.

Since warfarin inhibits the synthesis of the vitamin K-dependent clotting factors (II, VII, IX, X, protein C and S), in patients with protein C or S deficiency, warfarin leads to a transient hypercoagulable states.

Question 296

A 49-year-old man presents with obstructive jaundice (pruritus, dark urine, and pale stools) with palpable, nontender gallbaldder (Courvoisier sign). He has smoked two packs of cigarettes/day for the past 20 years.

Answer 296

Pancreatic adenocarcinoma.

• SMOKING is the most important environmental risk factor.
• CA 19-9.
• Migratory thrombophlebitis: redness and tenderness of veins on palpation of extremities (Trousseau syndrome)
  
  • Due to release of clotting tissue factors.
  • Presdisposes patients to higher risk of DVT.

Question 297

A 35-year-old African American woman presents to her gynecologist with lower abdominal pain. U/S reveals an embryonic structure implanted in the left fallopian tube. The patient is treated medically with a pharmaceutical agent. A few months later, she returns complaining of vaginal bleeding. Testing identifies an early-stage choriocarcinoma. Tx?

Answer 297

Methotrexate

• Antimetabolites: effective during S phase of DNA synthsis (along wih Azathioprine/5-FU); folic acid analogue that inhibits dihydrofolate reductase.
• Anti-inflammatory: inhibits AICAR; RA, psoriasis, IBD, vasculitis.
• Immunosuppressant, an abortifacient, or an antineoplastic agent.
• ADR:
  
  • hepatotoxicity,
  • as a folic acid analog, can cause neutral tube defects in infants,
  • myelosuppression that’s reversible with leucovorin (folinic acid, reduced to methylene tetrahydrofolate) ***

Question 298

After large blood transfusion, patient complains of signs & symptoms of hypocalcemiae (irritability, fatigue, muscle cramping and perioral paresthesias, Chvostek sign). Cause?

Answer 298

Blood is anticoagulated with sodium citrate and citric acid, and thus a massive blood transfusion is accompanied by a large dose of citrate.

Two possible complications: metabolic alkalosis and a decline in plasma free calciums.

Question 299

What are the classic pentad of thrombocytopenic purpura (TTP)?

Answer 299

• Fever
• Microangiopathic hemolytic Anemia*: schistocytes on peripheral blood smear
• Thrombocytopeniae*: petechiae
• Renal abnormalities
• Neurologic disturbances (headache, stroke, change in mental status).

* : required to make the diagnosis.

• Caused by deficiency of the metalloprotease that breaks down the ultralarge vWF multimers (ADAMTS13)–> intravascular platelet aggregation, creating partially thrombosed vessels.

Question 300

A patient who complained of distortion of straight lines now presents with loss of central vision (scotoma). Dx & Tx?

Answer 300

Age-related macular (central area of retina) degeneration:

• Dry (non-exudative): Prevent progression with multivitamin and antioxidant supplements.
• Wet (exudative): Treat with anti-VEGF (eg, ranibizumab, bevacizumab).

Question 301

A patient presents with an acute, but painless monocular vision loss. Opthalmic exam shows cloudy retina with attenuated vessels and “cherry-red” spot at fovea. Dx?

Answer 301

Central retinal artery occlusion

Internal carotid artery –> Ophthalmic artery –> central retinal artery.

Question 302

The effect of IV anesthetics (e.g., Thiopental) is terminated via:

Answer 302

Rapid resdistribution into tissue and fat, ↓ cerebral blood flow.

• Brain, kidney, liver, lungs, heart –> skeletal muscle, bone, fat.

Question 303

Neuromuscular blocking drugs

Answer 303

1. Selective for Nm nicotinic receptors at NMJ but not autonomic Nn receptors.
2. Succinylcholine: strong Ach receptor agonist that produces sustained depolarization and prevents muscle contraciton.

• Phase 1: Prolonged depolarization leading to equal reduction of all 4 twitches.
• Phase II: Repolarized.
• Hyperkalemia ***

3. Nondepolarizing:

• Competitive antagonist for postsynaptic AchR.
• Tubocurarine, atracurium, mivacurium, pancuronium, vecuronium, rocuronium.
• Reversed by neostigmine.

Question 304

• A newborn presents with tremor, irritability, and diarrhea.
• A mother’s PMH is significant for mental illness (eg, schizophreniae) and Hepatitis C.
• Dx?

Answer 304

• Result from illicit materal drug use or prescribed opiate use (eg, drug treatment program)
• At-risk newborns include those born to mothers with poor mental health, no prenatal care, and hepatitis C infection.
• Tx of choice for acute opioid withdrawal: opiate replacement: morpine or methadone.

Question 305

ADRs of opioid analgesics?

Answer 305

• Pruritus: IgE-independent mast cell degranulation.
• Constipation/miosis (tolerance does not develop).
• Contraction of smooth muscle cells in the sphincter of oddi: ↑ bile duct pressure.
• Addiciton.
• Respiratory depression.

Question 306

During delivery, an infant’s arm is pulled upward. How would this affect infant’s intrinsic hand muscles?

Answer 306

Klumpke palsy: traction or tear of lower trunk C8-T1 from sudden upward jerking.

• Lumbricals, interossei, thenar, hypothenar affected
• Total claw hand: lumbricals normally extend DIP and PIP joints.
• Involvement of the T1 nerve root proximal to the sympathetic trunk may cause concomitant Horner’s syndrome (eg, ipsilateral ptosis, miosis, anhidrosis).

Question 307

• Dermoepidermal junction aggregates of large cells that fuse with adjacnet nets.
• Individual atypical cells have irregular nuclear contours, hyperchromasis and are round or spindle-shaped.
• CDKN2A mutation on chromosome 9p21.
• Can evolve into melanoma.

Answer 308

• Melanoma is a relatively frequent source of metastatic lesions to the brain & has a tendency to hemorrhage.
• Vertical growth (invasion) associated with the highest risk of metastasis.
• Asymmetry, Border irregularity, Color variation, Diameter > 6mm, and Evolution over time.
• Often driven by activating mutation in BRAF V600E kinase
• 4 different variants: Superficial spreading, nodular, lentigo maligna, and acral lengitinous.

Question 309

Immune thrombocytopeniae

Answer 309

May be primary (idiopathic with no obvious causes) or secondary to autoimmune disorder, viral illness, malignancy, or drug reaction (e.g., acetaminophen, TMP/SMX)

• Anti-GpIIb/IIIa antibodies –> autoimmune destruction of platelets.
• Mucocutaneous bleeding and a mild petechial hemorrhage
• ISOLATED THROMBOCYTOPENIAE.
• Peripheral blood may show presence of large platelets occasionally.

Question 310

Infectious mononucleosis

Answer 310

• Caused by EBV (also associated nasopharyngeal carcinoma, primary CNS lymphoma, Hodgkin lymphoma, and Burkitt lymphoma).
• Classic symptoms: moderate to high fever, pharyngitis, hepatosplenomegaly, lymphadenopathy in adolescents and young adults.
• IgM (cold) -mediated hemolytic anemia (scleral icterus, decreased HgB level, increased reticulocyte count).
• Peripheral smear shows atypical cytotoxic T lymphocytes.
• Monospot test: heterophile antibodies are detected by agglutination of sheep or horse RBCs.
• Immortalization of B cells

Question 311

• Anemia, mild neutrophilia (variable), and mild thrombocytosis (variable).
• Bone marrow is gradually replaced by collagen fibrosis: unsuccessful bone marrow aspiration.
• “Tear drop” RBCs.

Answer 311

• Idiopathic myelofibrosis

Question 312

Most common type of non-Hodgkin lymphoma in adults:

• Constitutional “B” symptoms: low-grade fever, night sweats, weight loss/gain
• A biopsy of enlarged spleen shows sheets of large lymphocytes that stain positively for CD20.
• May be associated with immunosuppression: HIV, autoimmune diseases (eg, Crohn disease).

Answer 312

DLBCL:

• Richter transformation- CLL/SLL transformation into an aggressive lymphoma, most commonly diffuse large B- cell lymphoma.

Question 313

• Fatigue/weakness/pallor (anemiae)
• Mucosal bleeding, easy bruising (thrombocytopeanie)
• Recurrent infections (Leukopeniae)
• LOW RETICULOCYTE COUNT (<0 . 1%)
• NO HEPATOSPLENOMEGALY
• Chloramphenicol.

Answer 313

• Hypocellular marrow filled with fat cells and marrow stroma.
• Increased production of EPO by the peritubular cells of kidney (in response to anemiae-induced hypoxia) would be expected.
  *

Question 314

Limited use due to toxicity but often still used in developing countries because of low cost

Answer 314

• Anemiae (dose dependent)
• Apalstic anemia (dose independent)
• Gray baby syndrome ( in prematrue infants because they lack liver UPD-glucuronosyltransferase).

Question 315

A 7-year-old boy presents with fatigue, arthralgias, and discomfort in his left upper abdominal quadrant. His conjunctivae are pale and an enlarged liver and spleen are palpable. He has required multiple blood transfusions since he was very young.

Answer 315

B-thalassemia major

• Manifests as ineffective erythropoiesis, causing severe hemolysis and anemia
• 2° hemochromatosis due to transfusion: elevated blood glucose, restrictive cardiomyopathy.
  
  • Iron overload: hemosidern appears as brown or yellowish-bronw pigments in Kupffer cells.
• Extramedullary hematopoiesis –> hepatosplenomegaly.
  
  • Maxillary overgrowth and frontal bossing are associated with the characteristic “chipmunk facies”.

Question 316

A young African-American patient has a PMH of painful episodes requiring hospitalization. He now presents with painful, swollen, erythematous extremities. Dx ?

Answer 316

Sickle cell disease

• Substitution of valine (hydrophobic) for glutamic acid (hydrophilic)
• HbS polymerizes at low oxygen tension, causing sickling and hemolysis of erythrocytes and resultant vascular occlusion.
• Autoinfarction of spleen leads to scarring, fibrosis, and atrophy.
• Susceptible to infection by encapsulated organisms.
  
  • Howell-Jolly bodies.
• S.aureus is the most common cause of osteomeylitis in all groups, but Salmonella osteomyelitis has a particular association with SCD.

Question 317

• Triad of dermatitis (maculopapular rash), hepatitis (elevated LFT, jaundice, hepatosplenomegaly), and gastroenteritis (diarrhea)
• Usually seen in bone marrow transplantation patients weeks after transplantation.

Answer 317

Graft-vs-host disease.

• Donor lymphocytes reacting against major or minor histocompatibility antigens on recipient cells.

Question 318

• Aplastic crises in SCD.
  
  • Replicates in erythrocyte precursors in the bone marrow.
  • Diminised number of reticulotyes available to replace the deformed and/or remove erythrocytes.
• Erythema infectiosum (fifth disease): self-limiting; bright, blanchable erythema on the cheeks –> a lacy, reticular rash then ensues.
• Fetal hydrops in fetuses.
  
  • Pleural effusions, pericardial effusion, and ascites.

Answer 318

Parvovirus B19

• A nonenveloped ssDNA virus.
• Arthritis/arthralgia in adults.

Question 319

Clinical use for azathioprine (or 6 MP)?

Answer 319

1. Use:

• Preventing organ rejection, RA, IBD, SLE
• Used to wean patients off in chronic disease and to treat steroid-refractory chronic diseae

2. ADR:

• Myelosuppression *
• Increased toxicity with allopurinol or febuxostat.

Question 320

• Increase in PT/PTT coagulation time but paradoxically leads to recurrent arterial/venous thrombosis (eg, spontaenous abortions).
• Recurrent miscarriage as well as false positive syphilis tests.

Answer 320

• Patients with Lupus are at risk of developing acquired antiphospholipid antibody syndrome caused by lupus anticoagulant.

Question 321

• Defect in androgen receptor resulting in normal-appearing female.
• Female external genitalia with scant axillary and pubic hair, rudimentary vagina; uterus and fallopain tubes absent.
• Normal functioning testes often found in labia majora; surgically removed to prevent malignancy.
• ↑ testosterone, estrogen, LH

AIS

Answer 321

• Male pseudohermaphroditism: A small phallus & hypospadias are common.
• Ambiguous genitalia until puberty, when ↑ testosterone causes masculinization/↑ growth of external genitalia (eg, clitomegaly @ age 12).

5a-reductase deficiency

Question 322

• Dysfunction of NADPH oxidase.
• Susceptible to catalase-positive organisms that can destroy their own hydrogen peroxide:
  
  • S. Aureus.
  • Pseudomonas cepacia
  • Burkholderia cepacia.
  • Serratia marcescens.
  • Nocardia & Aspergillus
• Diffuse granuloma formation.
• Dihydrorhodamine (decreased fluorescent green compound); negative NBT test.

Question 323

• Cardiac defects: Tetralogy of Fallot, interrupted aortic arch, truncus arteriosus
• Craniofacial deformities (orbital hypertelorism, short palpebral fissures, cleft palate, bifid uvula).
• Thymic hypoplasia/aplasia –> Leading to T cell deficiency (CD3/CD28) & Underdeveloped paracortex of lymph nodes.
• Hypocalcemia –> tetany/seizures, Chvostek sign, Trousseau sign.
  *

Answer 323

Chr 22q11.2 deletion associated with failure of neural crest cell migrations

• 3rd pharyngeal pouch: inferior parathyroid, thymus (MG).
• 4th pharyngeal pouch: superior parathyroid glands, ultimobranchial body (parafollicular C cells).

Question 324

A patient presents with following signs & symptoms

• Lives in an older houe (probably painted with lead)
• Symptoms of abdominal pain, headaches, fusiness/decreased concentration, and inconsolability
• Burton lines (thin, black-blue lines on the gingiva due to lead deposition)
• “Lead lines”: dense radiographic lines at the metaphysis
• Microcytic, hypochromic anemiae.

Answer 324

Lead poisoning:

• Inhibits ALA dehydratase + ferrochelatase.
• Basophilic stippling: peripheral smear.
  
  • RBCs with dark-purple, punctate inclusions.
  • Inhibition of erythrocyte 5’ nucleotidase by lead results in ribosome aggregation due to inability to degrade RNA.
• Tx: Dimercaprol and EDTA.

Question 325

Folic acid deficiency would present as?

Answer 325

• Tetrahydrofolate form of folate (folic acid) functions as an intermediate in the transfer of 1-carbon units.
• NO neurologic symptoms; folic acid deficiency becomes evideny within a few months
• Increased homocysteine but normal methylmalonic acid levels

Question 326

Dysphagia (due to esophageal web) + Iron deficiency anemiae + koilonychia (spoon-shaped nails) + shiny red tongue (glossitis) secondary to atrophy of lingual papillae.

Answer 326

Plummer-Vinson Syndrome.

Question 327

Hyperviscosity syndrome:

• Bleeding.
• Dizziness.
• Headache.
• Visual/hearing disturbances.
• Raynaud phenomenon.

Answer 327

Waldenstrom macroglobulinemia.

High levels of IgM and a predominance of plasma cells in bone marrow

• Proteins are separated into albumin, α₁, α₂, β, γ regions, with the γ region corresponding to IGs.
• “M spike”: Any relative increase in Igs causing a spike in the γ region.

Question 328

A 7-year-old girl (children) presents with fever, fatigue, bone pain, generalized lymphadenopathy and petechiae. Her labs reveals anemia, thrombocytopeniae, and leukocytosis. Peripheral blood smear is shown. Dx & risk factors?

Answer 328

Acute lymphoblastic leukemia/lymphoma

• Weakness (due to anemia).
• Petechiae (thrombocytopeniae).
• Generalized lymphadenopathy/bone pain (rapid expansion of bone marrow)
• Stain positive for terminal deoxynucleotidyl transferase (TdT), a specialized DNA polymerase important for V(D)J recombination in both T and B lymphocyte precursors.
• B-ALL stains positive for CD10, CD19, and CD20
• T-ALL stains positive for CD3 and CD5 and presents with thymic mass.
  
  • Anterior mediastinal mass can cause superior vena cavae syndrome, dysphagia, dyspnea, stridor.
• Associated with Trisomy 21.

Question 329

A preadolescent patient presents with signs & symptoms of pancytopeniae, in conjunction with abnormal skin, skeletal/facial findings. Dx?

Answer 329

Fanconi Anemia,a DNA repair defect causing bone marrow failure:

• “dizzy spells”: presyncope and palpitations caused by anemia.
• Bleeding gums & nosebleeds: thrombocytoepniae
• Frequent infections: Leukocytopeniae
• Cafe-au-lait spots + congenital abnormalities (e.g., wide thumbs, small eyes, hypogonadism, microcephaly).
• Due to increased chromosomal breakage caused by a defect in multiprotein complex required for DNA repair, which ameks patients more sensitive to chemotherapy and radiation.

Question 330

Which chemotherapeutic agent is notorious for causing ototoxcity & nephrotoxicity?

Answer 330

Cisplatin:

• Works by cross-linking DNA, preventing DNA replication and interfering with cell division.
• Alopecia, N/V are common side effects of all chemotherapeutic agents.
• Cisplatin also results in ototoxicity and nephrotoxicty (can be rescued by amifostine).

Question 331

MOA of Etoposide/Tenoposide ?

Answer 331

Etoposide

• DNA topoisomerase II inhibitor
• Tx: small cell carcinoma of the lung, prostate, testicular carcinoma
• ADR: myelosuppression, alopecia, N/V.

Question 332

• Present during the first year of life with severe sun senstivity (e.g., erythema, scaling).
• Neurologic manifestations: unsteady gaint, peripheral neuropathy.
• Increased risk of basal cell carcinoma, squamous cell carcinoma, and melanoma.

Answer 332

Xeroderma pigmentosum:

• Nucleotide excision repair deficient
• UV radiation cross-links pyrimidine residues, and nucleotide excision (endonuclease) is required for DNA repair.
• +

Question 333

In a patient with liver cirrhosis (and/or hepatocelluar carcinoma), which is the most representative of the severity of organ involvement?

Answer 333

Increased prothrombin time (biosynthetic function).

Question 334

Squamous cell carcinoma of the bladder is caused by?

Answer 334

Schistosoma haematobium, freshwater snails.

• Urinary bladder venous plexus: S. haematobium
  
  • Characterized by ulceration & scarring of the bowel or bladder/ureters.
• Mesenteric venules of the intestine: S. japonicum, S. mansoni.
• Tx: Praziquantel.

Question 335

Target Cells

Answer 335

HbC

Asplenia

Liver disease

Thalassemiae

• Microcytic, hypochromic anemiae (+along with iron deficiency anemiae).

Question 336

Which agent used for breast cancer can cause endometrial carcinoma?

Answer 336

Tamoxifen:

• Selectively antagonizes estrogen receptors in the breast, thus inhibiting growth. Agonists at bone (osteoclasts apoptosis)
• Clinical use: breast cancer
• Agonist effect at endometrial tissues may increase the risk of endometrial carcinoma.

Raloxifen:

• No risk of endometrial carcinoma.
• Estrogen antagonistic activity on the breast: prevention of breast cancer.
• Supplement Tx for osteoporosis in postmenopausal women

Both can cause hot flashes/ thrombosis.

Question 337

What’s the MOA of a medication that’s highly effective for the prevention of chemotherapy-induced N/V (antiemetic) ?

Answer 337

Ondansetron/Granisetron

• 5-HT₃ receptor antagonist.

Question 338

A patient presents with non-tender, painless lumps in multiple areas of her body. These lumps have become larger and smaller in size during the past 5 years.

Answer 338

Follicular lymphoma

• t (14;18)- translocation of heavy-chain Ig (14) and Bcl-2(18)
• Bcl-2 inhibits apoptosis.

Question 339

A patient presents with jaundice, scleral icterus, and hemoglobinuria after starting primaquine. Furthermore, he has a first-degree male relative who has experienced a similar episode. Dx?

Answer 339

G6PD deficiency:

• Reduces NADP⁺ to NADPH, which in turn reduces glutathione (GSSG to GSH) via glutathione reductase.
• Caused hemolytic anemia: paleness/fatigue/shortness of breath, jaundice/scleral icterus/dark urine (indirect bilirubin)
• Oxidative stress: fava beans, antimalarias, viral infections.
• Blood smear: Bite cells, Heinz bodies.

G6PD oxidative is also required for fatty acid & cholesterol biosynthesis.

Question 340

An infant presents with cataracts and a failure to achieve developmental milestones. Possible DDx?

Answer 340

Classic galactosemiae:

• Absence of galactose-1-phosphate uridyltransferase.
• Symptoms develop when infant begins feeding (lactose present in breast milk and routine formulae).
• Jaundice, vomiting, hepatomegaly, renal dysfunction, E.coli sepsis, cataract, hemolytic anemiae.

vs. galactokinase deficiency
* Cataracts may be the only manifestation.

Autosomal recessive - as in most cases with enzyme deficiency.

Question 341

A patient presents with jaundice/scleral icterus following stress a couple days ago. CBC shows increased indirect bilirubin. His PMH is unremarkable. Dx?

Answer 341

Gilbert syndrome:

• Decreased level of UDP glucuronyl transferases following stress

vs.

Crigler-Najjar syndrome, type I:

• Absent UDP-glucuronyltransferase. Presents early in life & patients die within a few years.

Question 342

1. Hat size can be increased due to skull thickening; hearing loss is common due to auditory foramen narrowing.
2. Serum Ca²⁺, phosphorous, and PTH levels are normal. ↑ ALP.
3. Mosaic pattern of woven and lamellar bone.

Answer 342

Paget disease of bone

4 stages:

• Lytic : osteoclasts.
  
  • M-CSF, RANK-L important for osteoclastic differentiation & maturation
  • Tx: Osteoprotegerin (decoy protein) & Denosumab.
• mixed
• sclerotic
• quiescent

5. Increased risk of osteosarcoma.

Question 343

• 20-40 years old, more often in women.
• Epiphysis of long bones (often in knee region): arises most commonly at distal femur and proxmial tibia.
• Multinucleated giant cells that express RANK-L: “Soap bubble” on X-Ray.

Answer 343

Giant cell tumor (“osteoclastoma”)

Question 344

1. Bimodal distribution: 10-20 years old (1°) , > 65 (2°)
2. Predisposing factors: Paget disease of bone, retinoblastoma, bone infarcts, radiation, Li-fraumeni syndrome.
3. Metaphysis of long bones.
4. Codman triangle (elevation of periosteum) or sunburst pattern (pleomorphic malignant osteoblasts surrounded by abundant osteoid material) on X-ray.

Answer 344

Avoid teriparatide: Recombinant PTH analog given subcutaneously; increased osteoblastic activity.

Question 345

1. Boys < 15 years old.
2. Diaphysis
3. Anaplastic small blue cell malignant tumor.
4. “Onion skin”
5. t(11:22).

Answer 345

Ewing Sarcoma

Question 346

Seronegative spondyloarthritis: HLA-B27 (MHC class I serotype).

Answer 346

1. Psoriatic arthritis.
2. Ankylosing spondylitis.

• Common in young & middle-aged men.
• Presents with morning stiffness and low back pain.
• Destruction of articular cartilage with resulting stiffness and fusion of axial joints.
• Involvement of the thoracic spine and enthesopathies of the costovertebral and costosternal junctions can limit chest wall expansion.

3. IBD
4. Reactive arthritis

• “Can’t see (pink eye), Can’t pee, Can’t bend my knee (arthritis)” + rash.
• Following urogenital (eg, Chlamydia) or intestinal infection (Salmonella, Shigella, Campylobacter, Yersinia) in young male.
• Sterile joint aspirates.

Question 347

1. Endemic in developing countries (eg, recent migration).
2. A club-shaped, gram-positive rod. Often found in clumps (Chinese characters) or joined V- or Y-shaped chains on Cysteine-tellurite agar.

• Expressing diphtheria toxin that inhibits eukaryotic protein synthesis: Exotoxin A: ADP-ribosylation of EF2 ~ similar to P. aeruginosa.
• Pseudomembrane into the larynx & trachea
• Neck swelling & enlarged lymph nodes = “bull neck”
• Myocarditis & neurologic toxicity.

Answer 347

C. diphtheriae

• Diphtheriae antitoxin: passive immunization against toxoid.
• DTaP vaccine: active immunization.
• IgG against circulating _toxoid proteins ***,_ not the actual bacteriae.

Question 348

Patients with mild to moderate α and β, thalassemia have a microcytic, hypochromic anemia with minimal anistocytosis. Severe cases of alpha thalassemia can cause death in uero (hydrops fetalis).

Answer 348

Question 349

• Manifests within the first several months of life with hepatomegaly and severe hypoglycemia.
• ↑ Glycogen in liver, lactate, TG, uric acid (gout).

Answer 349

Deficiency of glucose-6-phosphatase

• von Gierke disease/ type 1 glycogen storage disease.

Question 350

A 4-year-old patient presents with decreased eye contact, increased startle, macrocephaly, seizures, ataxia, and cherry-red spots on macule. A patient dies within a few years of diagnosis. Dx?

Answer 350

Tay-Sachs disease:

• Hexosaminidase A deficiency–> accumulation of GM₂ ganglioside.
  vs. Niemann-Pick disease (+ cherry-red spots AND hepatomegaly.)
• Sphingomyelinase deficiency leads to sphingomyelin.

Question 351

• flank tenderness,
• a palpable abdominal mass,
• and (+/- painless) hematuria.
• Travel history of Sub-Saharan Africa
• Elevated HCT.

Answer 351

RCC

• Unusually clear cells with a cytoplasm rich in lipids and glycogen.
• Usually found in PCT.
• Associated with vHL syndrome (gene deletion on Chr.3)
• Associated with paraneoplastic syndroms: ectopic EPO(increased HCT), ACTH, PTHrP, renin.

Question 352

A 68-year-old African American man presents to his PCP complaining of worsening low back pain, urinary hesistancy, and occasional blood in his urine. Imaging reveals osteoblastic/sclerotic metastases to multiple vertebral bodies. Dx & Tx?

Answer 352

Adenocarcinoma of the prostate

• Prostate cancer spread to the lumbosacral spine via the vertebral venous plexus (VVP) –> prostatic venous plexus.
• Radionucleotide bone scan: several foci of increased uptake, where radioactive tracers have accumulated.
  
  • Constant back pain (not relieved by rest or positions) that worsens during night.
• Tx
  
  • Leuprolide.
  • Flutamide: inhibits interactions of testosterone and DHT with their receptors.

Question 353

A patient is being treated for dematophytes. What’s the MOA of an antifungal medication ?

Answer 353

1. Terbinafine: Inhibits squalene epoxidase.
2. Caspofungin: Inhibit cell wall synthesis by inhibiting synthesis of β-glucan.

Question 354

Which tumor-suppressor gene is implicated in Li-Fraumeni syndrome?

Answer 354

Li-Fraumeni syndrome:

• TP53 gene.
• Sarcoma (osteosarcoma), Leukemia, Adrenal, Breast cancer

Question 355

B-thalassemia major:

Answer 355

1. Presents with:

• Hemolytic (microcytic) anemiae
• Hepatosplenomegaly
• “Chipmunk facies”: maxillary overgrowth reflecting the extramedullary hematopoiesis in the bones of the face.

2. Requirement of the blood transfusions since birth
3. Increased HbF (α2γ2) HbA₂ (α2δ2); synthesis of a chain is intact; absence of HbA₁ (a2b2) supports an absence of B-chain syntehsis.

Question 356

An African-American fe/male patient presents with refractory HTN. Labs show hypercalcemia. What would CXR show?

Answer 356

Sarcoidosis:

• Other physical findings include erythema nodosum, arthralgias and hepatosplenomegaly.
• Elevated serum ACE levels
• Hypercalcemia due to increased 1α-hydroxylase-mediated vitamin D activation in macrophages.
• CXR: Hilar adenopathy and pulmonary infiltrates + noncaseating granulomas
• T_H1, IL-2, IFN-Y

Question 357

Pemphigus vulgaris vs. bullous pemphigoid

Answer 357

1. Pemphigus vulgaris

• IgG antibody against desmoglein, a component of desmosomes which connects keratinocytes in the stratum spinosum (type II hypersensitivity).
• Oral mucosa involved
• IF: antibodies around epidermal cells in a net-like pattern.

2. Bulluos pemphigod

• IgG antibody against hemidesmosome
• Spares oral mucosa
• IF: linear pattern @ epidermal-dermal junction.

Question 358

• Papules and plaques with silvery scaling, especially on knees & elbows.
• Acanthosis with parakeratotic scaling.
• ↑ Stratum spinosum; ↓ stratum granulosum
• Auspitz sign: pinpoint bleeding spots from exposure of dermal papillae.
• DEFORMING JOINT DISEASE.

Answer 358

Tx:

• Topical vitamin D analogues (eg, calcipotriene, calcitriol, tacalcitol).

Question 359

What does Leser-Trelat sign indicate?

Answer 359

Leser-Trelat sign: sudden appearance of multiple seborrheic keratoses, indicating an underlying malignancy.

Question 360

Vascular tumors (eg, hemangioma):

Answer 360

1. Angiosarcoma: Rare blood vessel malignancy typically occurring in the head, neck, and breast areas. Usually in elderly, on sun-exposed areas. Associated with radiation therapy and chronic postmastectomy lymphedema.
2. Glomus tumor: Benign, painful, red-blue tumor, commonly found under fingernails. Arises from modified smooth muscle cells of the thermoregulatory glomus body.
3. Pyogenic granuloma: Polypoid lobuated capillary hemangioma; associated with trauma and pregnancy.
4. Cherry (adult) hemangioma vs. Strawberry/superficial (infant) hemangioma.
   * Strawberry hemangioma initially grow & progressively regress.

Question 361

Miscellaneous skin disorders:

1. A patient presents with symmetric, hyperpigemtned thickening of skin, especially in axilla and/or neck. What underlying disorder may this patient have?
2. A patient with PMH of hepatitis C presents with pruritc, purple, polygonal, planar, papules and plaques. Dx?
3. Pityriasis rosea

Answer 361

1. Acanthosis nigricans:

• Insulin resistance: diabetes, obesity, Cushing syndrome; visceral malignancy.
• Hinders the anti-lipolytic effects of insulin, leading to lipolysis and release of FFA –> elevated FFA contributes to insulin resistance by impairing insulin-dependent glucose uptake and increasing hepatic gluconeogenesis.

2. Lichen planus:

• Wickham striae: reticular white lines.
• Saw tooth infiltrate of lymphocytes @ dermal-epidermal junction.

3. “Herald patch” followed days later by other scaly erythematous plaques, often in a “christmas tree” distribution of trunk. Self-resolving.

Question 362

A COX inhibitor that’s commonly used instead of aspirin to avoid Reye syndrome is associated with which ADR?

Answer 362

1. Overdose produces hepatic necrosis: jaundice, coagulopathy, hypoglycemiae, hepatic encephalopahty:

• NAPQI deplete glutathione and forms toxic tissue byproducts in liver
• N-acetylcysteine is antidote - regenerates glutathione.

Question 363

• GP1b deficiency; increased bleeting time but normal PT/aPTT
• (+/-) Thrombocytopeniae
• Abnormal ristocetin activity (upregulates Gp1b) that does NOT correct with mixing studies.

Bernald-Soulier syndrome

Answer 363

• GPIIb/IIIa deficiency; increased bleeting time but normal PT/PT
• Normal platelet count.

Glanzmann thrombasthenia

Question 364

Common chromosomal translocations?

Answer 364

Question 365

Methemoglobinemia?

Answer 365

Nitrites and benzocaine causes poisoning by oxidizing Fe²⁺ to Fe³⁺:

• Methylene blue increases conversion back to Fe²⁺, increasing hemoglobin oxygen content and overall oxygen delivery to body tissues.
• Fe³⁺ doesn’t bind oxygen effectively, but has increased affinity for cyanide (eg, almond odor).

Question 366

The patient presents with abnormal vaginal bleeding and decreased appetite with a discrete mass in her uterus. Histopatholgic image is shown. Dx?

Answer 366

Leiomyo/sarcoma:

• Spindle-shaped smooth muscle cells with varying degrees of atypia.
• Sarcomas are malignant neoplasms of mesenchymal origin.

Question 367

There are 350 nurses in the trial. The study finds that 238 have experienced between 3 and 7 needlesticks/year. Assuming a Gaussian distribtuion, approximately how many nurses have experienced more than 9 needlesticks/year?

Answer 367

350 * 2.5%= 9

Question 368

A patient treated for Plasmodium vivax returns to a patient complaning of fatigue and jaundice/scleral icterus. What medication was given?

Answer 368

Chloroquine eliminates the erythrocytic stage of his malaria infeciton; however, with P. vivax, a patient would still have exoerythrocytic parasites (hypnozoites) dormant in the liver –> Primaquine is effective in preventing disease relapse, but can also cause hemolytic anemia in G6PD.

• Can also cause torsades de pointes

Question 369

• Hemangioblastoma (foamy cells and is highly vascular) of the retina, cerebellum, medulla.
• Increased risk of developing bilateral RCC (flank pain, palpable flank mass, and hematuria).

Answer 369

• The deletion of the tumor-suppressing vHL gene on chromosome 3p causes VHL disease.
• AUTOSOMAL DOMINANT

Question 370

• Inhibit ADP-induced expression of GPIIb/IIIa via P2Y_{<strong>12</strong>} receptor.
• Treatment for coronary artery disease & ischemic stroke.
• As effective aspirin for prevention of CV events and should be used in patients with aspirin allergy.

Clopidogrel, prasugrel, ticlopidine

Answer 370

• GPIIb/IIIa inhibitor: same site where fibrinogen binds.

Abciximab, eptifibatide, tirofiban

Question 371

In the setting of ischemia (bowel ischemia), lactic acid is produce in the cytoplasm of the cell in anaerobic conditions and can cause an anion-gap metabolic acidosis.

Answer 371

Winter’s formulae:

• 1.5 X [HCO3^-] + 8 +/-2

Question 372

A patient presents with symptoms of calf pain and leg swelling following a business trip/flight. Dx?

Answer 372

DVT:

1. Virchow triad

• Stasis (immobility, obesity, CHF)
• Endothelial injury (trauma, surgery, previous DVT)
• Hypercoagulable state (pregnancy, OCP, coagulation disorders, malignancy)
• Increased risk in smokers.

2. TXA2, produced by platelets, stimulatest platele aggregation and vasoconstrction.

Question 373

Fanconi Syndrome.

Answer 373

• Generalized reabsorptive defect in PCT.
• Associated with ↑ excretion of nearly all amino acids, glucose, HCO₃^-,PO₄^3-.
• May result in metabolic acidosis (proximal renal tubular acidosis).

Question 374

Barter RTA: Reabsorptive defect in NKCC in thick ascending Loop of Henle

• Presents similiarly to chronic diuretic loop use.

Gitelman syndrome: Reabsorptive defect of NaCl in DCT.

• Presents similar to chronic HCTZ diuretic loop use.

Answer 374

Liddle syndrome: Presents like hyperaldosteronism, but aldosterone level is nearly undetectable.

• ↑ Na⁺ reabsorption in collecting tubules: results in HTN, hypokaelmia, metabolic alkalosis.
• Similar to Syndrome of Apparent Mineralcocorticoid Excess (hereditary deficiency of 11B-hydroxysteroid dehydrogenase).

Question 375

What causes hyperkalemia?

Answer 375

Digitalis (blocks Na⁺/K⁺ ATPase).

HyperOsmolarity.

Lysis of cells (e.g., crush injury, rhabdomyolysis, tumor lysis syndrome).

Acidosis.

B-B (blocks Na⁺/K⁺ ATPase).

High blood sugar (insulin deficiency; blocks Na⁺/K⁺ ATPase).

Succinylcholine.

Question 376

Which anticoagulant, used for emergency such as in DVT/PE, does not require monitoring?

Answer 376

LMWH, given subcutaneously, binds to antithrombin III, and predominantely inhibits factor Xa from converting prothrombin to thrombin.

• eg: Enoxaparin
• The use of LMWH does not require monitoring of the aPTT, so it can be adminstered on an outpatient basis.
• Safe in pregnancy
  *

Question 377

Days after beginning a cytotoxic chemotherapy regimen, a patient experiences significant pain in his left great toe, N/V, multiple excoriations on his extremities. His CBC shows increased potassium, phosphorus, and uric acid. Dx?

Answer 377

Tumor lysis syndrome:

• ↑ Uric acid (increased turnover of purine nucleotides)
• ↑ Potassium
• ↑ Phosphate (breakdown of intracellular ATP)
• Decreased calcium (precipitation with increased phosphate)
• Excess potassium and low calcium can both lead to heart arrhythmias/weakness.

Question 378

A pregnant patient who took TMP-SMX recently presents with increased indirect bilirubin level. Her fetus is at risk of?

Answer 378

Kernicterus, from indirect bilirubin deposited in basal ganglia.

Question 379

• Mature adults.
• Causes marrow fibrosis –> Dry tap on aspiration –> Pancytopeniae.
• Massive splenomegaly, but peripheral lymphadenopathy is rather uncommon.
• Stains TRAP – > replaced with flow cytometry.

Answer 379

Hairy cell leukemia: lymphocytes with cytoplasmic projections.

• Mature B-cell tumor that infiltrates the bone marrow & RES system.

Question 380

A 4-year-old girl presents with severe abdominal pain, nausea, hematemesis, hypotension, and tachypnea. She was diagnosed with acute iron overload. Tx?

Answer 380

Treat w/ deferoxamine.

Question 381

What are some examples of direct Factor Xa & thrombin inhibitors?

Answer 381

Direct factor Xa inhibitors:

• Apixaban
• Rivaroxaban
• Antidote: Andexanet alfa
• Increased PTT & PT/INR.

Direct thrombin inhibitors:

• Argatroban, bivalirudin, dabigatran.
• Increased thrombin time.

Preferred anticoagulants in the setting of AF. They’re taken orally and do not require weekly monitoring like warfarin does.

Question 382

Pathophysiology of retinoblastoma:

Answer 382

Characterized by diminished visual acuity and white pupillary reflex:

• Loss-of-function mutation in the tumor suppressor gene Rb: “two-hit” hypothesis.
• Rb binds and inactivates E2F, a TF involved in the progression of the cell cycle from G1 to S phase; phosphorylation of the Rb releases it, allowing E2F to become active.

Question 383

• 97% of alveolar surfaces.
• Line the alveoli.
• Squamous; thin for optimal gas diffusion.

Pneumocytes I

Answer 383

• Secrete surfactant from lamellar bodies:
  
  • ↑ Compliance.
  • ↓ Alveolar surface tension.
  • Prevent alveolar collapse.
• Cuboidal and clustered.
• Precursors to type I and other type II cells.
• Proliferate during lung damage.

Pneumocytes II

Question 384

What structures perforate diaphragm at T8? T10? T12?

Answer 384

T8: IVC, Phrenic nerve.

T10: Esophagus, Vagus.

T12: Azygose vein, Aorta, Thoracic duct.

Diaphragm is innervated by C3, 4, and 5. (phrenic nerve):

• Any abdominal process (ruptured spleen, peritonitis, hemoperitoneum) irritating the sensory fibers around the diaphragm can cause referred pain via the phrenic nerve to the C3-C5 shoulder region.

Question 385

Respiratory Equations

Answer 385

1. V_D = physiologic dead space = anatomic dead space of conducting airways plus alveolar dead space.

V_D=Tidal volume X (PaCO₂ - PECO₂ / PaCO₂)

• Physiologic dead space should be approximately equal to anatomic dead space.
  2. Ventilations
• Minute ventilation: V_E = V_T X RR
• Alveolar ventilation: V_A= (V_T-V_D) X RR

Question 386

Schistosomiasis

Answer 386

• A parasitic fluke infection that can cause Katayama fever, characterized by fever, hepatosplenomegaly, and peripheral eosinophilia.
• Consider katayama fever in otherwise healthy patients with recent travel history to middle east, sub-saharan africa, and south america, especially if the individual was exposed to sources of fresh water.

Question 387

A patient presents with palpitations and lightheadedness. EKG is shown. Which drug should be prescribed long-term to prevent future complications?

Answer 387

Warfarin.

Question 388

Prognosis of (Hodgkin’s) lymphoma is based on?

Answer 388

Ann Arbor staging system, which takes into account the extend of lymph node involvement as well as extranodal involvement.

Question 389

What precipitates sickling?

Answer 389

• Low oxygen levels
• Increased acidity.
• Low blood volume (dehydration).

Tx: HbF.

Question 390

Carbon monoxide poisoning? - Carboxyhemoglobin.

Answer 390

1. Poorly functioning heating systems, improperly vented fuel-burning devices, motor vehicles operating in poorly ventilated areas.
2. CO binds to the iron present in heme proteins with an affinity 250 X that of oxgyen.

• Normal Hb concentration.
• ↓ %O₂ saturation of Hb.
• Normal dissolved O₂ (PaO₂).
• ↓Total O₂ content.

3. Increased binding affinity of oxygen to remaining hemoglobins.

Question 391

• A 8-year-old child presents with recent-onset headache, bitemporal hemianopia.
• CT shows a calcified cyst in the suprasellar region.

Answer 391

Craniopharyngioma:

• Derived from remnants of Rathke’s pouch.
• Cholesterol crystals found in “motor oil”-like fluid within the tumor.

Question 392

• Bleeding from skin and mucosal sites.
• Heavy menstrual periods (menorrhagia).
• Nosebleeds (epistaxis)
• Prolonged bleeding following tooth extraction.

Answer 392

1. Serves as the ligand for platelet adhesion to an exposed subendothelial collagen by binding to platelet receptor GPIb.
2. vWF also serves as the plasma carrier of factor VIII.
3. Deficiency results in increased BT & aPTT.
4. Desmopressin can reverse vWF deficiency.
   * Increases vWF release from endothelial cells.

Question 393

Eosinophils

Answer 393

Defends against helminthic infections (MBP)

Question 394

A patient presents with hepatosplenomegaly, malaise, anemia, leukopenia, and weight loss. Dx?

Answer 394

• L. donovani* - microsocpically, macrophages containing amastigotes are observed.
• Tx: sodium stibogluconate.

Question 395

West Niles Virus?

Answer 395

• Flaviviridae: (+) icosahedral, enveloped RNA virus.
• A febrile viral illness with a rash and neurologic manifestations, including encephalitis associated with a flaccid paralysis syndrome.
• Most common in summer.

Question 396

Needle stick exposures carry a risk for exposure to blood-borne pathogens, not those transmitted by airborne or fecal-oral routes. Of these, HIV has a relatively low risk of infection, HEP. B is vaccine-preventable, and HEP. C has the highest risk of infection.

Question 397

A Japanese male presents with skin lesions, hepatosplenomegaly, generalized lymphadenopathy, and neurologic symptoms (sensory neuropathies, gait abnormalities, bladder dysfunction, and ED). CBC shows hypercalecmiae.

Answer 397

Adult T-cell lymphoma caused by HTLV

• Infected T cells demonstrate a characteristic multilobulated nucleus described as “cloverleaf”.

Question 398

• Thrombocytopeniae: Petechiae/purpura/hematemesis/epistaxis
• Eczema
• Increased risk of pyogenic infections, esp. against N. meningitidis, H. infleunzae, S. pneumoniae.

Answer 398

Wiskott-Aldrich syndrome:

Question 399

Pulmonary Emboli

Answer 399

1. Presentations:

• V/Q mismatch ***
• Hypoxemia (↓ PaO2) –> Tachypnea (respiratory alkalosis) –> ↓ Plasma HCO3^- compensation in approximately 48 hours.
• Sudden-onset dyspnea
• Pleuritic chest pain.
• Tachycardia.
• Large emboli or saddle embolus may cause sudden death.

2. Fat emboli - associated with long bone fractures/liposuction/classic triad of hypoxemia, neurologic abnormalities, petechial rash.

Question 400

Asbestosis:

Answer 400

• Shipbuilding, roofing, plumbing.
• Calcified, supradiaphragmatic and pleural plaques.
• Risk of bronchogenic carcinoma > mesothelioma.
• Only pneumoconioses affecting lower lobes.
• Asbestos (ferruginous) bodies.

Question 401

What’s the most common lung cancer in nonsmokers/women and overall?

Answer 401

Adenocarcinoma:

• Activating mutations include KRAS, EGFR, and ALK.
• Glandular patterns on histology, often stains mucin (+)
• Bronchioloalveolar subtype: grows along alveolar septa –> apparent thickening of alveolar walls/ tall columnar cells containing mucous.

Question 402

Dx?

Answer 402

Paget disease:

• Results from underlying DCIS (ducts distended by pleomorphic cells with prominent central necrosis without extension beyond ductal basement membrane; microcalcifications) or invasive breast cancer.
• Eczematous patches on nipple.

Question 403

Intraductal papilloma

Answer 403

1. Most common cause of alarming unilateral bloody or serosanguneous nipple discharge in a premenopausal woman.
2. Caused by a proliferation of papillary cells in a duct or cyst wall with a fibrovascular core and may contain foci of atypic or DCIS.

Question 404

Phyllodes tumor

Answer 404

• Large, bulky tumors that can cause ulceration of the overlying epidermis.
• Have cystic spaces with “leaf-like” projections and myxoid contents.
• Most are benign.

Question 405

Invasive lobular carcinoma?

Answer 405

Orderly row of cells (single file/parallel) due to decreased E-cadherin expressions.

Question 406

Aldesleukin

Answer 406

Recombinant IL-2 promotes the proliferation, differentiation, and recruitment of lymphoid cells (NK cells). It’s used to treat RCC, and is thought to promote immune-mediated antitumor effect.

Question 407

Live-attenuated vaccines:

• Induces both cellular and humoral responses.
• BCG, influenza (intranasal), MMR, polio (oral; Sabin), rotavirus, varicella, yellow fever.

Answer 407

Inactivated or killed vaccine: does not induce cellular response (MHC class I antigen-processing pathway).

• Rabies ***
• Influenzae (Injection)
  
  • Neutralizing antibodies against the hemagglutinin antigen: prevents the live virus from entering cells via endocytosis.
• Polio (salk)
  
  • Preferred in the developed countries - cannot revert to a virulent form.
• Hepatitis A.

Question 408

Viral vs. Fungal meningitis?

Answer 408

Viral: Normal or slightly elevated opening pressure, elevated lymphocytes, normal to increased protein level, normal to decreased glucose levels.

• HSV: begin treatment with acyclovir immediately.
• CMV, enterovirus (most common)

Fungal: elevated opening pressure, elevated lymphocytes, elevated protein, and decreased glucose.

• Cryptococcus

Question 409

A 53-year-old woman presents to the clinic because of abdominal pain and a 5.4 kg (12-lb) weight loss during the past month. U/S reveals bilateral ovarian masses consistent with malignancy. On histopathologic examination, metastasis is suspected due to presence of off-center nuclie and cytoplasm that stains heavily for mucin.

Answer 409

Krukenberg tumors

• malignancies in the ovaries that are metastases from a primary tumor, usually located in the GI.
• Histologically, the overproduction of mucin pushes the nucleus to the side of the cell, producing the characteristic “signet ring” morphology: plaquelike appearance, ill-defined, infiltrate large areas of the stomach wall, causing a “leather-bottle stomach” (linits plastica; thickened stomach wall).

Question 410

Squamous cell lung carcinoma?

Answer 410

• Centrally located.
• Smoking.
• Keratin pearls/intercellular bridges.
• PTHrP: hypercalcemiae.

Question 411

A 7-year-old African-American boy presents with a history of prolonged bleeding following procedures (eg, dental extractions, surgeries), and right knee pain and swelling (hemarthrosis). Dx?

Answer 411

Hemophilia A:

• an X-linked disorder caused by factor VIII deficiency
• Spontaneous bleeding into deep soft tissues (muscle), easy bruising, and hemarthrosis into weight-bearing joints (hip,knee, ankle).
• tx infusion of factor VIII.

Hemophilia B:

• factor IX deficiency; 5 times less common than Hemophilia A.

In either case, adminstration of thrombin (factor II) will make up for the deficiency and lead to blood clotting.

Question 412

• ↑ IgM
• ↓↓IgG, IgA, IgE.

Answer 412

• Most commonly due to defective CD40L on Th cells, leading to class switching defect.
  
  • Occurs by splicing out DNA coding for different types of the heavy chain constant region until the desired isotype is reached.
• Recurrent sinopulmonary, GI, and opportunistic infections (Pneumocystis, Cryptosporidium).

Question 413

A 2-year-old boy is brought to a clinic because of a large, unilateral, painless, abdominal mass his mother noticed while bathing him. She also has noticed a slight pink tinge to the boy’s urine. While performing an U/S-guided biopsy, the technician notes the kidney calyces on the right are highly distorted by a mass.

Answer 413

Nephroblastoma (Wilms tumor):

• Arises from neoplastic embryonic renal cells of the metanephros (eg, blastema).
• Can be associated with WAGR syndrome, Denys-Drash syndrome, and Beckwith-Wiedemann syndrome (hemihypertrophy).
• Deletion of tumor suppressor gene WT1 on Chr. 11

Question 414

HIV-infected patient presents with purple-colored, painless plaques on his upper back. Dx?

Answer 414

HHV-8, also known as Kaposi’s sarcoma.

• Lesions can affect lungs, GI, and biliary tract..
• Spindle-shaped tumor cells with small-vessel proliferation.
• Tx: Interferon alfa-2b (Also effective for hepatitis B/C, leukemias, malignant melanoma).

Question 415

Paroxysmal noctural hemoglobinuria?

Answer 415

A rare acquired disorder caused by mutation in PIGA gene, which helps synthesize the GPI gene. Absence leads to uncontrolled complement-mediated intravascular hemolysis & hemosiderin in the urine.

• CD55/59 (-) RBCs on flow cytometry.
• Mesenteric vein thrombosis.
• Chronic hemolysis with breakdown of iron-containing erythrocytes can also lead to iron deposition in the kidney (hemosiderosis).

Question 416

Under what circumstances would following RBCs be seen?

Answer 416

DIC results from activation of the coagulation cascade.

• Deposition of microthrobi (leading to schistocytes) and consumption of platelets, fibrin, and coagulation factors with subsequent bleeding.
• Decreased platelet count, elevated bleeding time, elevated PT/PTT, elevated D-dimer/fibrin degradation products.

Common causes:

• Gram-negative urosepsis, malignancy, pancreatitis, trauma, transfusion reactions.
• Obsteteric complications (amniotic fluid embolism):
  
  • Amniotic fluid causes occlusion and vasospasm of the maternal pulmonary circulation, leading to left ventricular failure, decreased CO, and a severe ventilation-perfusion mismatch.
  • Fetal squamous cells and mucin in the maternal pulmonary artereis.

Question 417

Fibroadenoma:

• Most common in women < 35 years old.
• A solitary, well-demarcated, non-tender, firm, and mobile nodule.
• Increase in size during pregnancy, lactation, or with estrogen therapy and usually regress after menopause.
• Proliferation of myxoid stroma that encircles epithelium-lined glandular and cystic spaces: may compress and distort the surrounding glandular epithelium.
• Benign.

Answer 417

Fat Necrosis:

• Post-traumatic
• Irregular Mass
• Ecchmosis
  *

Question 418

Orotic aciduria?

Answer 418

Inability to convert orotic acid to UMP (pyrimidine) because of defect in uridine 5’-monosphosphate (UMP) synthase.

• Failure to thrive, developmental delay, megaloblastic anemia refractory to folate and B₁₂, and elevated urinary orotic acids.
• No hyperammonemia (vs. ornithine transcarbamylase deficieincy- orotic acid with hyperammonemia).
• Supplement with uridine.

Question 419

• =Increased orotic acid in blood and urine <— Excess carbamoyl phosphate
• Symptoms of hyperammonemia <— Impaired ammonia excretion.
  *

Answer 419

Ornithine transcarbamylase deficiency:

• Combines ornithine and carbamoyl phosphate to form cirtrulline.
• No megabloblastic anemia (vs. orotoic aciduria).

Question 420

Carbamoyl phosphate synthetase II is an enzyme that catalyzes teh inital step in de novo pyrimidine synthesis and is located in the cytosol.

Question 421

An infant who has been exclusively breastfed (and/or with small amount of baby formulae) presents with lethargy. CBC shows anemia.

Answer 421

Microcyctic (decreased MCV) hypochromic anemia due to iron deficiency.

Question 422

A 52-year-old woman presents with fatigue/arthritis/hyperpigmented skin/elevated LFT/hyperglycemiae/dilated cardiomyopathy.

Answer 422

Hereditary hemochromatosis: Hemosiderin (rion) can be identified on liver MRI or biopsy with Prussian blue stain.

• “Bronze diabetes”
• Tx: Phlebotomy + deferoxamine.
• Premenopausal menstrual bleeding in female slows the disease progression.

Question 423

Blistering cutaneous photosensitivity and hyperpigmentation

Answer 423

Porphyria cutanea tarda:

• Uroporphyrinogen decarboxylase deficiency.

Question 424

Blood transfusion therapy:

Answer 424

1. FFP/Prothrombin complex concentrate:
   * ↑ Coagulation factor levels: DIC; cirrhosis; immediate anticoagulation reversal.
   * Antidote for warfarin toxicity.
2. Cryoprecipitate:
   * Treat DIC (contains coagulation factors).
3. Risk factors: iron overload; hypocalcemia (citrate is a Ca²⁺ chelator); hyperkalemia.

Question 425

• Androgen excess: Hirsutism, acne, androgenic alopeciae.
• Ovarian dysfunction: Menstrual irregularities.
• Insulin resistance: Acanthosis nigricans, glucose intolerance/diabetes, metabolic syndrome.
• Obesity.

Answer 425

PCOS:

• Enlarged ovaries with cysts.
• LH > FSH
• Complications: Endometrial hyperplasia (increased in glands: stroma) & carcinoma.

Question 426

1. Clomiphene:
   * Results in inhibition of estrogen-negative feedback on the hypothalamic-pituitary-ovarian axis, and a subsequent increase in pulsatile GnRH secretion.
2. Anovulation:
   * Exogenous hCG –> alpha subunit of hCG is structurally similar to LH and therefore stimulates LH surge.
3. OCP for treating hirsutism

• Suppress LH secretion from the pituitary, thereby decreasing ovarian androgen production.
• Increase BHG synthesis by the liver, decreasing free testosterone levels.

Answer 426

PCOS Tx.

Question 427

Risk f(x) for breast cancer?

Answer 427

• Early menarche.
• Late menopause.
• Delayed first pregnancy (>30 years old) & Nulliparity.
• Family history.

Question 428

Trastuzumab (Herceptin)

Answer 428

Monoclonal antibody against HER-2 (c-erbB2), a tyrosine kinase receptor:

• ADCC
• ADR: cardiotoxicity.

Question 429

Bortezomib/carfilzomib

Answer 429

Boronic-acid containing proteasome inhibitors

• Inducing arrest at G2-M phase & apoptosis.
• Clinical use: Multiple Myeloma, mantle cell lymphoma (11;14)
• ADR: peripheral neuropathy, herpes zoster reactivation

Question 430

T_reg

Answer 430

1. Help maintain specific immune tolerance by suppressing CD4 and CD8 T-cell effector functions.
2. Identified by expression of CD3, CD4, CD25, and FOXP3.
3. Activated regulatory T cells produce anti-inflammatory cytokines (IL-10, TGF-B)
4. IPEX: genetic deficiency of FOXP3.

• Immune dysregulation.
• Polyendocrinopathy.
• Enteropathy.
• X-linked.

Question 431

Sheehan syndrome

Answer 431

Associated with ischemic necrosis of the anterior pituitary caused by blood loss and hypovolemic shock during delivery:

• Hormonal loss of FSH, LH, ACTH (cortisol deficiency) , TSH, Prolactin (decreased lactation; primary complaint), GH

Question 432

A patient presents with aquagenic pruritus, facial plethora, and splenomegaly. Dx?

Answer 432

Polycythemia verae, a chronic myeloproliferative disorder characterized by:

• Erythrocytosis & low EPO level.
• Leukocytosis
• (Mild) thrombocytosis
• Splenomegaly ***
• JAK/STAT (nonreceptor cytoplasmic tyrosine kinase) mutation rendering hematopoietic cells more sensitive to growth factors such as EPO & thrombopoietin.

Question 433

1. Primary (polycythemia verae) & secondary polycythemia are absolute erythrocytosis (increased total RBC mass).
2. EPO-producing tumors (e.g., RCC, hepatocellular carcinoma) or hypoxia can cause secondary polycythemia due to abnormal EPO production. Workup will show an elevated EPO level.

• Only RBC increases.
• Combination of multiple elevated cell lines and splenomegaly is unlikely.

Answer 433

Normal RBC mass indicates a relative erythrocytosis secondary to dehydration & excessive diuresis.

Question 434

Consequences of splenectomy & splenic rupture & (spleen is the most commonly injured organ with blunt abdominal trauma) & SCD.

Answer 434

1. Target Cells:
   * HALT
2. Howell-Jolly bodies
3. Increasing susceptible to encapsulated bacteria:

• Pseudomonas aeruginosa,
• S. pneumoniae ***
• H. influenzae *** (vaccination only against typeable & encapsulated Hib antigen).
• N. meningitids *** (C5-C9 can lead to recurrent infections).
• E. Coli,
• Salmonella,
• Klebesiella,
• GBS.

Question 435

Which medication can be used to treat ER (+) breast cancer in postmenopausal women?

Answer 435

Anastrozole;

• Aromatase inhibitor that selectively blocks estrogen production.
• In postmenopausal women, the greatest source of estrogen is the conversion of androstenedione, produced in the adrenal glands, to estrone through aromzation in liver, muscle, and fat.

Question 436

Hgb-O2 dissociation curve

Answer 436

Question 437

The vast majority of CO₂ is transported in the blood as ?

Answer 437

HCO₃^-

• The enzyme CA in RBC converts CO₂ to HCO₃^-
• Facilitated by HCO₃^- and Cl^- transporter.

Question 438

A patient presents with headache, flushing, dyspepsia, and cyanopia (blue-tinted vision). What could be included in his PMH?

Answer 438

ED/Pulmonary HTN

• May have been taking sildenafil/vardenafil/tadalafil.
• Inhibit PDE-5 –> ↑ cGMP –> prolonged smooth muscle relaxation in response to NO.

Question 439

• Recurrent pyogenic infections by staphylococci and streptococci.
• Partial albinism.
• Progressive neurodegeneration: nystagmus, neuropathy.

Answer 439

Defect in lysosomal trafficking regulator gene (LYST).

• Microtubule dysfunction in phagosome-lysosome fusion —> abnormal giant lysosomal inclusions.

Question 440

Transplant rejection

Answer 440

1. Hyperacute: within minutes.

• Type II hypersensitivity reaction
• Preformed antibodies against graft in recipient’s circulation.
• Widespread thrombosis of graft vessels & fibrinoid necrosis.
• Gross mottling & Cyanosis.

2. Acute: (1-4) Weeks to months.

• Type IV hypersensitivity reaction: Cellular (CD8⁺ T cells) + Humoral.
• Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate.
• Prevent/reverse with immunosuppressants.

3. Chronic: Months to years.

• Type IV hypersensitivity reaction: Cellular (CD4⁺ T cells) + Humoral.
• Proliferation of vascular smooth muscle, parenchymal atrophy, interstitial fibrosis
• Bronchiolits obliterans: small airways.

Question 441

A natural response is elicited by a conditioned stimulus that was previously presented in conjunction with an unconditioned stimulus

Answer 441

Classical conditioning (as opposed to operant conditioning).

Question 442

2 years:

• Walks up/down stairs with both feet on each step.
• Jumps.
• Builds a tower of 6 cubes.
• 50+ word vocabulary/2-word phrases.
• Parallel play.
• Toilet training.

Answer 442

3 years:

• Alternating feet.
• Rides tricycle.
• Copies a circle.
• Uses utensils.
• 3-word sentences.
• Knows age/gender.
• Imaginative play.

Question 443

1. 3.3 half-lives to reach 90% of the steady-state level & 4-5 half-lives to reach steady-state.
2. t_1/2 = (0.7 X V_d) / Clearance
   * CL= (rate of elimination of drug)/ (plasma drug concentration)
3. Maintenance dose= Steady-state plasma concentration (Cp_ss) X CL / [Bioavailability fraction]
   * Bioavailability usually 1 for medications administered intravenously.
4. In patients with renal or hepatic impairment, the loading dose remains unchanged, but the maintenance dose is decreased.

Question 444

After degradation (by proteasome), antigen-derived peptides enter the rough endoplasmic reticulum (RER) by ATP-dependent transport via TAP (transporters associated with antigen processing) proteins.

Answer 444

MHC class I molecule.

Question 445

1. Thayer-Martin media contains vancomycin, colistin, and nystatin; drugs used to select for N. gonorrhoeae.
2. Tx: Ceftriaxone + oral azithromycin (to treat Chlamydia trachomatis).
3. An infection with N. gonorrhoeae does not result in lasting immunity because of the ability of these bacteria to modify their outer membrane proteins (eg, pillus) by the process of antigenic variation.

Answer 445

• N. gonorrhoeae*
• Gram (-) diplocci; intracellular.

Question 446

Imipenem

Answer 446

Co-administered with cilastatin, an inhibitor of dehydropeptidase-1, an enzyme in the brush border of the PCT that metabolizes imipenem.

Question 447

Bartonellae (cat scratch disease) vs. Pasteurella multocida (cats & dogs)

Answer 447

1. Bartonellae:

• Fever + regional (axillay) lymphadenopathy + scratches
• Gram (-); visualized by Warthin-Starry stain.
• Cause Bacillary angiomatosis.

2. Pasteurella multocida:
   * Fever + rapid inflammation/cellulitis/purulent drainage + scratches.

Question 448

An 8-week-old boy has had developmental delay since birth. On examination, the child has normal vital signs, coarse facial features, diffuse joint stiffness, clawhand deformities, and kyphoscolosis. Muscle biopsy reveals numerous intracytoplasmic inclusions in cells.

Answer 448

I-cell disease:

• Defect in N-acetylglucosaminyl-1-phosphotransferase–> failure of Golgi apparatus to phosphorylate mannose residues
• Proteins are secreted extracellularly rather than delivered to lysosomes (increased hydrolase).

Question 449

• (+) direct Coombs test
• Anemiae
• Jaundice (–> Kernicterus).
• Hydrops fetalis: characterized by collection of fluid in two or more body compartments (subcutaneous tissue, abdomen, pericardium, pleura).
• Release of immature, nucleated erythrocytes and leads to persistent extramedullary hematopoiesis.

Answer 449

Rh hemolytic disease of the newborn (erythroblastosis fetalis)

• Type II hypersensitivity.
• Prevention: Administration of anti-D IgG (RhoGAM)
• Immediate Tx (in case of hemolysis): exchange transfusion with matched Rh-negative blood.

Question 450

Lesch-Nyhan syndrome:

Answer 450

1. Defective purine salvage due to absent HGPRT, which converts hypoxanthine to IMP and guanine to GMP.
2. Intellectual disability, self-mutilation, aggression, hyperuricemia, gout, dystonia.
3. May cause megaloblastic anemia: overproduction of de novo purine synthesis.

Question 451

1. Tuberculoid:

• Limited to a few hypoesthetic, hairless skin plaques
• High-cell mediated immunity with a largely Th1-type immune response.
• Milder ***

Answer 451

2. Lepromatous:

• Low-cell mediated immunity with a humoral Th2 response.
• Diffuse skin thickening, plaque-like hypopigmentation, leonine facies, paresis, regional anesthesia, testicular destruction.
• Skin, superficial nerves (eg, Schwann cells), eyes, and testes.

3. Tx: Dapsone/rifampin/ + clofazimine for lepromatous form.

Question 452

• A pleomorphic, gram-variable rod involved in bacterial vaginosis.
• A gray vaginal discharge with a fishy smell.
• Loss of lactobacilli & overgrowth of anaerboic bacteria in vagina.
• Clue cells (vaginal epithelial cells) covered with Gardnerella have stippled appearance along outer margin.
• Tx: Metronidazole & Clindamycin.

Answer 452

Gardenella vaginalis

Question 453

Vaginitis

• Foul-smelling, yellow or greenish discharge; itching and burning.
• Trophozoites (motile) on wet mount (saline microscopy).
• “Strawberry cervix”.

Answer 453

Trichomonas vaginalis

• Tx: Metronidazole for patient & partner
  
  • Can potentially cause disulfiram-like reaction if patient is simultaneously drinking alcohol.

Question 454

• Enlarged lymph nodes.
• Recurring fever (due to antigenic variation).
• Somnolence.
• Coma.
• Dx: Trypomastigote in blood smears.

Answer 454

African sleeping sickness.

• Trypanosoma brucei - Tsetse fly.
• Tx: Suramin for blood-bonre disease or melarsoprol for CNS penetration.

Question 455

1. Norovirus

• Icosahedral capsid, naked, ss-RNA, nonsegmented.
• Acute onsent; resolves in 2-3 days
• Vomiting and/or diarrhea (no blood or mucous).
• Outbreaks in crowded settings (school, hospitals, cruise ships, nursing homes).
• The most common cause of viral gastroenteritis in children in resource-rich countires (U.S.) ***

Answer 455

2. Rotavirus

• Icosahedral capsid, naked, ds-RNA, segmented.
• Decline in incidence/prevalence due to vaccination ***

Question 456

A disorder in myelin formation due to defective very long chain and branched-chain fatty acid oxidation or synthesis in peroxisome:

Answer 456

1. Adrenoleukodystrophy
2. Refsum disease:

• Anosmia
• Vision loss
• Progressive muscle weakness & wasting
• Poor balance & coordination (ataxia)
• hearing loss
• dry, scaly skin (ichthyosis).

3. Zellweger syndrome:

• Craniofacial abnormalities (e.g.,widened sutures, large anterior fontanelle)
• Hepatomegaly
• Profound neurologic defects (hypotonia, seizures, developmental delay).

Question 457

• Hypopigmented, hyperpigmented, or erythematous macules or patches on the upper body.
• Hot & Humid climates.
• Often most visible after extensive sun exposure due to tanning of the adjacent skin.

Answer 457

Question 458

1. MOA: Binds tightly to the D-alanyl-D-alanine portion of cell wall precursors, thereby blocking glycopeptide polymerization and inhibiting bacterial cell wall synthesis.

• IV: serious MRSA infections
• ORAL: severe C. difficile pseudomembranous colitis.

2. ADRs: Red man syndrome (preventable with slow infusion & antihistamines), nephrotoxicity, ototoxicity.

Question 459

Answer 459

Nerve is not contained within femoral sheath.

Question 460

Drug of choice for terminating PSVT?

Answer 460

Adenosine.

ADRs: Flushing, hypotension, chest pain, sense of impending doom, bronchospasm.

2. Valsalva maneuever: rectus abdominis preodminant muscle.

Question 461

Essential fructosuria: Fructose intolerance

Answer 461

1. Essential fructosuria:

• Hereditary deficiency of fructokinase
• Fructosemia and fructosuria.
• Positive copper reduction test: nonspecifically detects the presence of reducing sugar: fructose, glucose, and galactose
• Negative glucose oxidase test.

2. Hereditary deficiency of aldolase B:

• Symptoms presents following consumption of fruit, juice, and honey.
• Symptoms: hypoglycemiae (fructose-1-phosphate and depletion of inorganic phosphate inhibit glycogenolysis and gluconeogenesis), jaundice, cirrhosis, vomiting.

3. Remains able to metabolize fructose due to compensatory activity of hexokinase.

Question 462

Selective IgA deficiency

• Usually asympatomatic
• Increased risk of upper/lower respiratory infections & gastroenteritis (giardiasis).
• Autoimmune disease (eg, celiac disease)
• Anaphylaxis during blood product transfusions.

Answer 462

Leukocyte adhesion deficiency (Type I)

• Defect in LFA-1 integrin (CD18) protein on phagocytes; impaired migration and chemotaxis; autosomal recessive.
• Defect in PECAM-1: affects transmigration.
• Delayed separation of the umbilical cord.
• Recurrent cutaneous infections without pus
• Marked peripheral luekocytosis with neutrophilia.

Question 463

The pathogenesis of certain bacteria is dependent on the expression of a temperate bacteriophage exotoxin, a process known as lysogenic conversion. Examples inlcude

Answer 463

• GAS.
• Botulinum toxin.
• Cholera toxin.
• Diptheria toxin.
• Shiga Toxin.

ABCD’S.

Question 464

What are some evidences of child/elderly abuse?

Answer 464

• Spiral fractures of the extremities: Unlikely to happen when a child “falls”
• Multiple bruises at various stages of healing
• Abdominal trauma
• scattered circular burns (cigarette burns)
• subdural hematomas (eg, shaken baby syndrome).
• retinal hemorrhages
• MUST BE REPORTED IN ALL 50 STATES.

Question 465

• Obligate intracellular organism.
• Lab diagnosis: cytoplasmic inclusions (reticulate bodies) seen on Giemsa or fluorescent antibody-stained smear

Answer 465

Types D-K:

• Urethritis
• PID: lower abdominal pain that worsens during coitus; presents with discharge, proctitis, fevers and chills.
  
  • Lead to chronic pelvic pain, infertility, etopic pregnancy, Fitz-Hugh-Curtis syndrome.

Types L1, L2, L3.

• Lymphogranuloma venereum
• Small, painless ulcers on genitals
• SWollen painful ingula lymph nodes that ulcerate (buboes).

Question 466

Serratia marcescens

Answer 466

A gram-negative rod that produces red pigment, often in the setting of CVC rather than UTI.

Question 467

Neuraminidase inhibitors block the normal function of viral neuraminidase enzymes to prevent the release of viral progeny from infected cells.

Answer 467

Oseltamivir and zanamivir

• Effective against both influenza A and B.
• used for both tx and prophylaxis.

Question 468

Which intermediate of TCA cycle inhibits the rate-limiting enzyme of glycolysis and activates the rate-limiting enzyme of fatty acid synthesis?

Answer 468

Citrate:

• Inhibits PFK-1, which converts fructose-6-phosphate to fructose-1,6-bisphosphate.
• Activates Acetyl-CoA Carboxylase, which converts acetyl-CoA to Malonyl-CoA.

Question 469

A 17-year-old girl is brought to the physician by her mother who’s concerned that her daughter is losing weight. The daughter is 165 cm tall and wights 44.5 kg. She’s wearing multiple layers of clothing, and yet complains that the office is cold. Physcial examination reveals her body is covered by soft, fine hair.

Answer 469

Anorexia Nervosa:

• Excessive dieting
• Intense fear of gaining weight
• Body image distortion
• Lanugo
• Stress fracture & osteoporosis
• Functional hypothalamic amenorrheae.
• Enlarged parotid glands (if binge/purge type)
• Cardiac atrophy, cardiomyopathy, arrhythmias.
• BMI < 85% of ideal body weight (vs. bulimina nervosa) = Weight (kg) / Height² (m²)

Question 470

Edward syndrome (trisomy 18)

Answer 470

Prominent occiput

Rocker-bottom feet

Intellectual disability

Nondisjunction

Clenched fists

low-set Ears

Congenital heart disease.

Question 471

• Gingival swelling/bleeding.
• Petechiae & Ecchymoses (anemiae).
• Poor wound healing.
• Perifollicular hemorrhages and coiled (corkscrew) hairs.

Answer 471

Vitamin C deficiency (eg, alcoholics, the poor, and the elderly) causes sCurvy due to a Collagen synthesis defect:

• Decreased hydroxylation of proline and lysine into hydroxyproline and hydroxylysine in RER.

Question 472

A microbiology laboratory is investigating the possibility of using enzymes as a novel class of antibacterial. These enzymes cannot traverse the double-layer lipid membrane. Instead, they bind directly to the surface of peptidoglycans and hydrolyze bonds within them.

Answer 472

gram (+) with thick cell walls; e.g., S. aureus.

• Penicillins, cephalosporins, and vancomycin are able to disrupt the peptidoglycan cell wall –> can induce osmotic stress.

Question 473

• Spirochete with hook-shaped ends found in water contaminated with animal urine.
• Flu-like symptoms, myalgias, jaundice, photophobia with conjunctival suffusion (erythema without exudate).

Answer 473

LEPTOSPIROSIS

Question 474

Darunavir

Indinavir

Ritonavir

Answer 474

1. Protease inhibitors used to treat HIV infection through inhibition of HIV-1 protease.
2. ADRs: GI upset, hyperglycemiae, lipodystrophy (Cushing-like syndrome & fat redistribution).

FLASH CARD ***

Question 475

S. aureus

Answer 475

1. Protein A binds with the Fc protion of IgG antibodies at the complement-bindig site.
2. TSST: Superantigens that bind to MHC class II and TCR.
   * Tampons & Nasal packing.
3. Causes acute bacterial endocarditis with rapid onset of symptoms, including shaking chills (rigors), high fever, dyspnea on exertion, and malaise. In IV drug users, it can cause right-sided endocarditis with septic embolization into the lungs.
4. Main culprit of organ abscess.
5. Acute food poisoning due to ingestion of preformed toxin.

Question 476

Quantifying risk

Answer 476

1. Incidence: (# of new cases) / (# of people at risk)
2. Risk: Divide the number of affected subjects by the total number of subjects in the corresponding exposure group.

Relative risk:

• Ratio of probability of the event occurring in the exposed group vs. control.
• [A/(A+B)] / [C/(C+D)]

3. Prevalence: (TP+FN) / (TP+FP+FN+TN).
4. Odd ratio: (A/C) / (B/D) = AD/BC

5. NNT= 1/ ARR

• ARR: ER_control - ER_treatment
  6. NNH= 1/ Absolute risk increase.
• Adverse event rate in the experimental group - adverse event rate in control group.
  7. PPV/NPV: depends on the prevalence of the population.
  8. Case fatality: Dividing the number of fatal cases of a disease or condition by the total number of people with that disease or condition.

Question 477

Quantifying risk 2

Answer 477

ARR:

• Control event (eg, disease) rate - Experimental event (eg, disease) rate.
• NNT= 1/ ARR.

Question 478

In which instance is parental involvement NOT required for a non-emancipated minor?

Answer 478

1. Sex: Contraception, Pregnancy, STDs

2. Drugs: Addiction.
3. Rock ‘n roll: Trauma and Emergency.

2/3 of states require parental conset prior to abortion; one-third require parental notification, but not consent.

Question 479

Kawashiorkor

Answer 479

Question 480

A 13-year-old girl recently returned from spending a day in the woods with the Girl Scouts. Upon returning, she started to complain of a rash that began on her wrists/ankles and spread inwardly to her trunk. Her blood test reveals antibodies that react with the Proteus antigen.

Answer 480

Rickettsia rickettsii:

• “Centripetal” pattern of spread
• Positive Weil-Felix reaction

vs. Rickettsia typhi
* Centrifugal: spreads outward, not intward.

Question 481

Hanta virus

Answer 481

Bunyaviridae: (-) helical; enveloped; circular RNA virus.

• (Hemorrhagic) pulmonary edema –> respiratory distress
• Deer mice feces.

Question 482

Type II Pompe disease:

Answer 482

Lysosomal acid α-1-4 glucosidase (acid maltase) deficiency

• Pathologic accumulation of glycogen within liver and muscle lysosomes.
  
  • Cardiac & skeletal muscles are particularly susceptible, as ballooning lysosomes intefere with contractile function.
• Cardiomegaly, hypotonia, and hepatomegaly.

Question 483

Kertagener syndrome:

Answer 483

A defect in dynein that prevents effective movement of cilia:

• Sinusitis
• Bronchiectasis
• Situs inversus
• Male & female infertility.

Question 484

• Pruritus ani.
• Diagnosed by seeing egg via the Scotch tape test.
• Albendazole; pyrantel pamoate.

Question 485

HPV

Answer 485

1. Koilocytes (perinuclear vacuolization) due to viral particles.
2. CIN refers to atypical squamous cells and is classified as low-grade squamous intraepithelial lesions (if extending <1/3 of the epithelium) or high-grade squamous intraepihtela lesions (if expanding beyond basal cells)
3. Has a tropism for stratified squamos epithelium, including the anal canal/vagina/cervix (condylomata acuminatum), and true vocal cords.

Question 486

Mullerian aplasia:

Answer 486

• Variable uterine development + upper vagina (short vagina)
• Primary amenorrhea
• Normal ovaries, which secret estrogen –> regular devleopment of secondary sexual characteristics.

Question 487

• Heartburn.
• Regurgitation.
• Dysphagia.
• Nocturnal cough, Hoarsenss.

Answer 487

GERD:

• GE junction incompetence.
• Histologic findings (from chronic inflammation).
  
  • Basal zone hyperplasia.
  • Elongation of the lamina propria papillae.
  • Scattered eosinophils & neutrophils.
• PPI usually result in symptomatic improvement.

Question 488

A 22-year-old caucasian male presents to the ER with abodminal pain that started around his belly button, then moved to the right lower abdominal quadrant.

Answer 488

Appendicitis:

• Incited by obstruction of the lumen: fecaliths, hyperplastic lymphoid follicles, foreign bodies, or tumors.
• RLQ, N/V, diarrhea, fever.

Question 489

Bilateral ligation of the internal iliac artery can decrease uterine blood flow and control postpartum hemorrhage in case uterine massage & uterotonic medications (eg, oxytocin) fails.

Answer 489

internal iliac artery

Question 490

Selection Bias?

Answer 490

The studied sample does not represent the general population.

• Before the study, with randomization of study participants to different arms of the study
• End of the study if researchers do not account for high dropout numbers.
• eg) Berkson bias: choosing hospitalized patients as control group.

Question 491

Recovery vs. immunized hepatitis serologic markers.

Answer 491

Recovery: Anti-HBs; Anti-HBc IgG

Immunized: Anti-HBs

Question 492

Exceptions to informed consent?

Answer 492

1. Patient lacks decision-making capacity or is legally incompetent.
2. Implied consent in an emergency (e.g. unconsciouss)
3. Therapeutic privilege: witholding information when disclosure would severly harm the patient or undermine informed decision-making capacity.
4. Waiver: Waives/refuses the right of informed consent.

Question 493

Macrolides (azithromycin, erythromycin)

Answer 493

Bacteriostatic antibiotics that bind to the 23s rRNA of the 50S ribosomal subunit and block ribosomal translocation (and thus protein synthesis).

• MOA: Gastrointestinal motility issues, arrhythmia caused by prolonged QT interval, acute cholestatic hepatitis, Rash, eosinophilia.

Question 494

Species of Plasmodium

Answer 494

P. ovale**/vivax: 48-hour cyclic fever

P. falciparum: irregular fevers; cerebral involvement

P. malarie: 72-hour cyclic fever

Question 495

Macrophage secrets IL-12, which causes naive helper T cell to differentiate into a T_H1 cell –> T cell secrets IFN- γ in turn, stimulating macrophages to increase antigen presentation and lysosome production.

Answer 495

Langerhans giant cells are characteristic of granulomatuos conditions, including the caseating granulomas associated with M. tubuerculsois infection.

• Multiple nuclei peripherally oranized in the shape of a horsehose.

Question 496

Positively skewed: Median < Mean

Negatively skewed: Mean < Median

Question 497

Ehlers-Danlos syndrome (EDS)

Answer 497

• Hyperextensible skin
• Hypermobile joints
• Easy bleeding & bruising
• Joint dislocation, organ rupture, berry aneurysm leading to ↑ SAH (vascular type; deficient type III collagen).
• Due to impaired N-terminal propetide removal.

Question 498

• Dysostosis multiplex (eg, enlarged skull, abnormally shaped ribs and vertebrae)
• Corneal clouding
• ACcumulation of heparan sulfate and dermatan sulfate due to a-L-iduronidase deficiency.

Question 499

Psoas muscle

Answer 499

Major hip flexor: vital in standing up from a supine position.

• Psoas abscess: Pain is exacerbated by movements that cause the psoas muscle to be stretched or extended, such as extension of the hip.

To assess for appendicitis:

• When the right hip is hyperextended, the iliopsoas muscle group pushes against the appendix and causes significant pain & irritiation.
• Innervated by the lumbar plexus –> femoral nerve.

Question 500

Indication of abnormal/pathologic grief

Answer 500

Excessive, intense, prolonged grief, as well as grief that’s delayed, inhibited, or denied.

• Hallucination not always pathologic ***

Question 501

Lead-time bias

Answer 501

A new screening tool touts longevity when in reality the disease process remains the same, but was detected at an earlier time.

Question 502

Mitochondrial-inherited disease.

Answer 502

1. Leber hereditary optic neuropathy: Bilateral vision loss.
2. Myclonic epilepsy with ragged-red fibers: Myoclonic seizures and myopathy-associated wtih exercise. Skeletal muscle biopsy shows irregularly shaped muscle fibers.
3. Mitochondrail encephalomyopathy with lactic acidosis and storke-like episodes (MELAS).
4. Heteroplasmy:
   * Variable severity of these diseases is explained by the random distribution of normal and mutated mitochondria between daughter cell during mitosis.

Question 503

Deep peroneal nerve vs. superficial peroneal nerve.

Answer 503

1. Deep peroneal nerve

• Responsible for dorsiflexion & toe extension.
• Found in anterior compartment with anterior tibial artery.

2. Superifical peroneal nerve:

• Eversion of the ankle.
• (Sensorry) Lateral compartment.

3. Tibial nerve:

• Responsible for plantar flexion (gastrocnemius and soleus).
• Posterior compartment (+posterior tibila artery)
• Responsible for sensation in the sole of the foot.

4. All branches of SCIATIC NERVE.

Question 504

1. PR3-ANCA/C-ANCA (antineutrophil cytoplasmic antibodies).
2. Triad:

• Focal necrotizing vasculitis
• Necrotizing granulomas in the upper airway (perforation of nasal septum/chronic sinusitis/otitis media/mastoiditis) and lung.
• Necrotizing glomerulonephritis.

3. May progress to negative IF/pauci-immune RPGN.

Answer 504

Question 505

Type 1 inteferons are important in the host response to viral infections.

Answer 505

In addition to inducing increasing MHC class I expression, IFN-a and IFN-B induce the synthesis of several host proteins, which act to inhibit viral replications.

Question 506

Enterococcus

Answer 506

A common cause of nosocomial urinary tract infection (in males) & subacute endocarditis & biliary disease:

• Gamma-hemolytic, catalase-negative, group D gram-positive cocci in chains that can grow in hypertonic saline and bile.
• Can be caused by cystoscopy and/or colonoscopy.
• Ampicillin
  
  • If ampicillin resistant, vancomycin
  • For VRE, linezolid is commonly used.

Question 507

The stastical power of a test (1-β) refers to the probability of correctly rejecting the null hypothesis when it is false, and it can be enhanced by?

• β: probabilty of concluding that there is no difference between grups when one truly exists.

Answer 507

Increasing sample size.

Question 508

• Most often found in posterior fossae in children.
  
  • Cerebellum: Loss of balance, incoordination.
• Glial cell origin, GFAP (+)
• Rosenthal fibers
• Cystic + Solid (gross)

Answer 508

• Pilocytic (low-grade) astrocytoma:

Question 509

Glitazones/thiazolidinediones

Answer 509

MOA: Binds to PPAR-γ nuclear transcription regulator

• ↑ FFA uptake
• ↑ Adiponectin production
• ↑ insulin sensitivity / Decreased insulin resistance.
• ↓ TNF, leptin production.

ADR: Weight gain, Edema, HF.

Question 510

Brown pigment gallstones

• Bacterial or helminthic infection of the biliary tract.
• B-glucuronidase released by injured hepatocytes and bacteria hydrolyzes bilirubin glucuronides to unconjugated bilirubin.
• Clonorchis sinensis has a high prevalnce in East Asian countries; common cause of pigment stones.

Answer 510

Black

• Chronic hemolysis
  
  • Sickle cell anemia, B-thalassemia, hereditary spherocytosis.

Question 511

When glycogen stores are depleted during fasting, ketone bodies are produced in the liver and can be used as an energy source in the mitochondria of peripheral tissues except?

Answer 511

Erythrocytes lack mitochondria and are unable to use ketones.

Question 512

Granulation tissue (Type III collagen - primarily affected in Ehlers-Danlos) seen approximatley 10 days following an acute M.I.

• Collagen: GLY-X-Y

Answer 512

Later replaced by Type 1 collagen (found in tendons) as infarct matures.

Question 513

TCA:

Answer 513

Amitriptyline, nortriptyline, doxepin:

• Inhibits NE & 5-HT reuptake.
• Sedation (histamine), Orthostatic hypotension (alpha-1 adrenergic blocker), atropine-like side effects (anticholinergic).
  
  • Dry mouth, blurred vision, dilated pupils
  • Urinary retention, flushing, hyperthermiae.
• Severe hypotension.
• Tri-C’s: Convulsions, coma, cardiotoxicity (Sodium channel inhibition - Most common cause of death).

Overdose Tx: Sodium bicarbonate.

Question 514

A patient presents with hypotension, hyperkalemiae, metabolic acidosis, and skin & mucosal hyperpigmentation. Dx & Tx?

Answer 514

Dx: Addison disease

• Presenting symptoms: hypotension/shock, N/V/abdominla pain, weakness, fever.
• ↓Corticosteroid levels: hyponatremia, hyperkalemiae, hyperchloremia (non-anion gap metabolic acidosis). hypoglycemiae.
• ↑ACTH, ↑POMC, ↑MSH (hyperpigmentation)
• Metyrapone stimulation test
• Tx: Dexamethasone + fludrocortisone

Question 515

A patient presents with refractory hypertension as well as weakness and paresthesias. CBC shows hypokalemiae and metabolic alkalosis. Dx?

Answer 515

Aldosterone-secreting tumor (Conn syndrome) or bilateral hyperplasia (idiopathic hyperaldosteronism) leading to hyperaldosteronism:

• Hypokalemia: muscle weakness & paresthesias.
• Metabolic alkalosis.
• Low plasma renin activity.
• Hypernatremia and pedal edema are rarely observed: Increased RBF (GFR) & ANP –> Increased Na⁺ excretion.
• Tx: Spironolactone, Eplerenone.

Question 516

Lac operon:

Answer 516

E.coli produces lactose-metabolizing enzymes only when it must use lactose as an energy source:

• Low glucose: cAMP increases, binds to CAP, a regulatory molecule that binds to DNA and facilitates the binding of RNAP to the lac operon.
• High lactose: Allolactose binds to repressor, detaching it from the operator locus just upstream of the lac genes.

Prokaryotic: polycistronic mRNA: synchronous production of enzymes in response to lactose.

Question 517

First-line medication for hypertensive emergency

• Systolic blood pressure > 180 mm Hg and/or a diastolic blood pressure > 120 mm Hg WITH end-organ involvement
  
  • eg, papilledema.

Answer 517

Nitroprusside: metabolized to NO and causes potent vasodilation of arterioles and venules.

Labetalol & carvediolol: can block both β & α-adrenergic, but should be used with caution in asthmatics and patients with COPD.

Question 518

A patient presents with a period of extremely elevated mood and productivity (manic episode) and one major depressive episode and.

Answer 518

Bipolar I disorder (mood swings)

Tx: Lithium

• Low thyroid (constipation, dry skin, hair loss, weight gain).
• Heart (Ebstein anomaly).
• Insipidus.
• Unwanted movements.
• Thiazide diuretics limit sodium reabosorption in the distal tubule, cauisng mild volume depletion that stimulates proximal tubular sodium/lithium reabsorption, leading to toxicity.

Question 519

Patients have the right to refuse Tx based on religious grounds (Jehovah’s witnesses), however, recent court decisions have determined that parents cannot refuse life-saving treatments for their children on this basis.

Answer 519

The Health Care Consent Act allows a physician to treat an incapacitated patient without consent in an emergeny setting.

Question 520

Causes an undulating fever with malaise, lymphadenopathy, and hepatosplenomegaly.

Normal route of exposure: ingestion of the organism, which may be found in products of infected animals (unpasteurized milk, undercooked meat).

Answer 520

Brucella

Question 521

Caused by twisting of the spermatic cord, resulting in compression of the pampiniform plexus of the testciular vein and reduced venous outflow.

Answer 521

Gonadal artery arises from the AA.

Genitofemoral nerve: loss of cremasteric reflex.

Question 522

t-RNA

Answer 522

tRNA is a small, non-coding form of RNA that contains chemically modified base (eg, dihydrouridine, ribothymidine, pseudouridine).

CCA sequence at the 3’ end of the tRNA recognize the correct aminoaycl-tRNA synthetase.

Question 523

During both steps of ethanol metabolism, NADH is generated from NAD+.

Answer 523

1. Increased NADH/NAD ratio:

• Inhibits all other pathways requiring NAD+, including reactions required for gluconeogenesis.
• In particular, lactate cannot be converted to pyruvate, and instead the reaction is driven from pyruvate toward lactate. In addition, conversion of malate to oxaloactate is inhibited.
• Pyruvate & oxaloacetate are intermediates in gluconeogenesis.

2. Excess NADH inhibits FFA oxidation, thereby diverting FFA away from lipolysis to the formation of TG. This contributes to hepatic steatosis in alcoholic patients.

Question 524

Th17 fails to produce IL-17, leading to an inability of neutrophils to respond to chemotactic stimuli:

• Staphylococcal abscesses that lack the expected warmth and erythema: cold abscesses.
• Eczema.
• Coarse facies.
• Retained primary teeths.

Answer 524

Hyper-IgE syndrome (Job syndrome)

Question 525

MHC 1:

• Composed of 3α chains and 1 β₂-globulin.
• Ubiquitin ligase: Recognize specific protein substrates and attach a ubiquitin tag. The proteins are then degraded to an appropriate size and coupled with the MHC I protein complex in the E.R.

Answer 525

MHC 2:

• 1α and 1β heterdimer peptides.
• Antigens loaded following release of invariant chain in an acidified endosome (eg, lysosomes).

Question 526

Transformation occurs when a cell takes up DNA from a donor cell, which is why when two types of bacteria are grown in mixed culture, some might survive bactericides that could kill each type individually, unless DNAse is added to destory DNA spilled into the medium before cells can absorb it.

Question 527

Daclizumab & basiliximab :

Answer 527

IL-2 receptor antibodies.

Question 528

Pathogenesis:

• Most common mutation is impaired post-translation processing leading to protein being retained in RER and not transported to cell membrane
• ATP-gated Cl^- channel in lungs & GI tract:
  
  • ↑ Intracellular Cl^- results in compensatory ↑Na⁺ reabsorption via epithelial Na⁺ channels –> ↑ H₂O reabsorption.
  • More negative transepithelial potential difference.

Answer 528

Clinical manifestations:

• Recurrent sinopulmonary infections (S. Aureus & P. Aeruginosa).
• Infertility due to absent vas deferense (azoospermia).
• Pancreatic insufficiency: Fat malabsorption with deficiens of the fat-soluble vitamins A, D, E, K and frequently occurs in patients with CF.
  
  • Supplement with pancreatic lipase.

Question 529

Infants biliary atresia:

Answer 529

Obstruction of extrahepatic bile ducts that presents with jaundice, dark urine, and acholic stools in the first 2 months of life due to conjugated hyperbilirubinemia.

Biopsy reveals intrahepatic bile duct proliferation, portal tract edema, and fibrosis.

Question 530

• Serum sickeness-like syndrome with joint pain, lymphadenopathy, and a pruritic urticarial vasculitis rash.
• Hepatomegaly
• Elevated ALT/AST

Answer 530

1. Sexual (among both heterosexual partners and men who have sex with men) and percutaneous (IV drug use, needle-stick accidents, blood transfusions).
   * VACCINE available.
2. Replicates via: (partial) dsDNA –> (+) RNA template –> (partial) dsDNA progeny.

• Viral DNA integration into the host genome may explain its progress into hepatocellular carcinoma.
• Liver biopsy: large hepatocytes filled with finely granular, homogeneous, pale pink cytoplasm (ground-glass).

3. Perinatal hepatitis B infection: high viral load & HBeAg positive.

Question 531

Physicians should routinely ask their patients about the use of herbal preparations and nutritional supplements and advise them on the quality, safety, and efficacy of the products.

Question 532

Retroperitoneal abdominal organs: SAD PUCKER

Answer 532

Suprarenal glands

Aorta & IVC

Duodenum (except 1st part)

Pancreas (head & body): frequent cause of retroperitoneal hamatomas following severe blunt or penetrating abdominal trauma.

Ureters & bladder

Colon (ascending & desending)

Kidney

Esophagus

Rectum (mid-distal)

Question 533

During gluconeogenesis, which substances directly stimulates the first enzyme?

Answer 533

Acetyl-CoA stimulates pyruvate carboxylase to convert pyruvate into oxaloacetate.

Question 534

A 13-year-old boy presents with progressive difficulty breathing, hoarseness, and dysphagia. Oropharyngeal examination reveals a large, red lingual mass. The patient subsequently undergoes excision of the mass; histopathology preparation of the recovered tissue is shown. Dx?

Answer 534

The thyroid gland is formed from evagination of the pharyngeal epithelium and descends to the lower neck.

Due to failure of migration, the tyroid can reside anywhere along the thyroglossal duct’s usual path, including the tongue.

Question 535

• Abdominal distension
• Bilious emesis
• Green inspissated mass (dehydrated meconium) in the distal ileum

Answer 535

Meconium ileus, found in patients with CF.

• In the US, pneumoniae, bronchiectasis, and cor pulmonale account for most deaths due to CF.

Question 536

Cholera toxin (eg, ETEC).

Answer 536

1. Activates adenylate cyclase in intestinal epithelial cells, leading to increased cyclic adenosine monophosphate; enhanced chloride efflux and decreases sodium reabsorption
2. Massive watery diarrhea —> flecks of mucus and sloughed epithelial cells, but no leukocytes or erythrocytes.
   * No invasion

Question 537

Amanita phalloides:

Answer 537

Amatoxins: potent inhibitors of RNAP II (mRNA synthesis).

Question 538

What would cause chronic gastritis.

Answer 538

Mucosal inflammation, often leading to atrophy (achlorhydria –> hypergastrinemiae) and intestinal G- cell metaplasia.

1. H. pylori

• Affects antrum first and spreads to body of stomach.
• Increases risk of PUD, MALT lymphoma.

2. Pernicious anemiae:

• Autoantibodies to parietal cells (found in upper glandular layer in lamina propria) and IF.
• Decreased parietal cell mass, Increased pH, increased gastrin.

Question 539

Anal fissures

• Longitudinal tears in the mucosa
• Due to passage of hard stools in patients with chronic constipation.
• Most fissures occur at the posterior midline, likely due to decreased blood flow in this area.

Answer 539

Internal hemorrhoids

• Drain into superior rectal vein –> inferior mesenteric vein.
• No somatic sensory innervation & cannot cause pain.
• Inferior hypogastric plexus.

External hemorrhoids

• Originate below the dentate lines, covered by modified squamous epithelium and have cutaneous (somatic) nervous innervation from the inferior rectal nerve, a branch of the pudenal nerve.
• Inferior rectal vein –> Internal pudendal vein.

Question 540

A patient presents with symptoms of cirrhosis, fatigue, jaundice, and pruritus. Dx?

Answer 540

Primary biliary cholangitis:

• A chronic liver disease characterized by autoimmune destruction of the intrahepatic bile ducts and CHOLESTASIS.
• Similar pathophysiology to GVH (lymphocytic infiltration).
• Increased elevated alkaline phosphatse and cholesterol, elevated serum IgM, anti-mitochondrial antibodies.
• Associated with other autoimmune conditions (eg, Sjogren syndromes).

Question 541

T2DM: Middle-aged populations.

Answer 541

Visceral obesity as measured by waist circumference or waist-to-hip ratio is an important predictor of insulin resistance.

Relative rather than absolute insulin deficiency, often with high total insulin levels that suppress ketone formation.

Question 542

The patient presents after a recent surgery with signs and symptoms consistent with drug-induced liver injury, most likely due to:

Answer 542

Halogenated inhaled anesthetic use (eg, halothane, enflurane, isoflurane, sevoflurane, desflurane)

• Markedly elevated serum aminotransferase levels due to massive hepatocellular apoptosis.
• Prolonged prothrombin time due to failure of hepatic synthetic function.
• Acute, highly lethal fulminant hepatitis: rapid atrophy and liver appears shrunken on autopsy.
• Can also cause increased ICP ***

Question 543

Which amino acids are transmembrane?

Which amino acids are seen in histones?

Answer 543

Nonpolar, hydrophobic amino acids.

Arginine, Lysine.

Question 544

Dx?

Answer 544

Bicornuate uterus:

• Incomplete fusion of Mullerian ducts
• ↑ risk of complicated pregnancy,e arly pregnancy loss, malpresentation, prematurity.

Question 545

Gonococcal cervicitis:

Answer 545

1. clinical features:

• Purulent or mucopurulrent discharge
• Friable cervix with easy bleeding (e.g., intermenstraul or postcoital bleeding)

2. Dx: nucleic acid acmplification testing
3. Tx: 3rdgeneration cephalosporin + azithromycin/doxycycline
4. Complications: PID –> scarring of the fallopain tubes from salpingitis –> inferitlity.

Question 546

Cephalic and gastric phases stimulate gastric acid secretion, while intestinal influences tend to reduce post-prandial gastric acid secretion.

Answer 546

The ileum & colon release peptide YY, which binds to receptors on the endocrine, histamine-containing cells described as ECLs.

Question 547

Hypoglycemiae can be precipiated by ____ in patients with insulin-treated diabetes. Uptake of glucose by skeletal muscle is mediated by the GLUT4, which is translocated to the cell membrane in response to insulin and muscle contraction.

Answer 547

Exercise.

GLUT4: insulin-dependent glucose transporters

• Adipose tissue.
• Striated muscle.
• Facilitated diffusion.

Question 548

Which can be useful in determining whether an elevated alkaline phosphatase is of hepatic or muscle origin?

Answer 548

GGTP.

Question 549

The 3rd part of the duodenum courses horizontally across the abdominal aorta and inferior vena cavea at the level L3. Which artery could be occluded from malignancy?

Answer 549

SMA

Question 550

Presents with dysmenorrhea, menorrhagia, uniformly enlarged, soft, globular uterus.

Answer 550

Adenomyosis:

• Extension of endometrial tissue (glandular) into uterine myometrium.

Question 551

• Menorrhagia.

Answer 551

• Multiple discrete tumors; benign smooth muscle tumor.
• Subserosal leiomyomas (fibroids) often cause irregular uterine enlargement, resulting in pelvic pressure.
• Fibroids arising from the posterior subserosal surface of the uterus can cause constipation due to pressure on the colon.

Question 552

Which lipid-lowering agents can increase triglycerides?

Answer 552

Bile acid-binding resins (eg, cholestyramine, colestipol, colesevelam):

1. Diversion of hepatic cholesterol to synthesis of new bile acids, increased uptake of LDL cholesterol from the circulation, and reduce blood LDL levels.
   * Hepatic cholesterol reduction is an activating factor for HMG CoA reductase and subsequently results in increased hepatic cholesterol synthesis.
2. ADR: increase hepatic production of TG and increase the release of TG-heavy VLDL particles into the circulation.

Question 553

t

Question 554

During starvation, which enzyme would be upregulated to maintain ketones and blood glucose values?

Answer 554

1. HSL: catalyzes mobilization of stored TGs into FFAs and glycerol.

• Glycerol: used primarily as a carbon source of gluconeogenesis
• Liver oxidizes FFAs to Acetyl-CoA, which can then be further metabolized to ketone bodies or shunted into TCA cycle to generate energy for gluconeogenesis.

2. Exceptions: Brain (FFAs do not cross BB so only ketone bodies/glucose can be used)
3. Erythrocytes: can use only glucose due to lack of mitochondria.

Question 555

• Hypoglycemia, hepatomegaly, ketoacidosis
• Muscle weakness, hypotonia
• Cytosolic accumulation of glycogen with abnormally short outer chains (limit detrans)

Answer 555

Debranching enzyme (alpha-1,6-glucosidase) deficiency.

Question 556

Epithelial (serous) ovarian cancer:

• Typically present with a pelvic mass, ascites, and peritoneal metastasis that result in decreased appetite, abdominal distension, and bowel or bladder changes (constipation, urinary frequency).
• CA-125.
• BRCA mutations & Repeated ovulations are at significantly increased risk for ovarian cancer.

Answer 556

Protective factors:

• Combined OCPs.
• Multiparity.
• Breastfeeing.
• Salpingo-oophorectomy.

Question 557

Sequeale of prolactinoma:

Answer 557

High levels of prolactin suppress GnRH from the hypothalamus, leads to hypogonadism (low estrogen)

• Anovulation, and amenorrhea
• Low bone density & vaginal dryness from decreased estrogen.

Question 558

• Blood: Increased chylomicrons, TG, and cholesterol level.
• Clinical: Pancreatitis, hepatosplenomegaly, eruptive/pruritic xanthomas, creamy layer in supernatant.

Answer 558

Hyperchylomicronemia:

• LPL or apolipoprotein C-II (cofactor for LPL) deficiency

Question 559

Cholecystitis

Answer 559

1. Acute calculous cholecystitis:

• Gallstone impaction in the dystic duct resulting in inflammation and gallbaldder wall thickening.
• Failed gallbladder visualization on radionuclide biliary scan due to cystic duct obstruction.

2. Acalculous cholecystitis: An acute inflammation of the gallbladder in the absence of gallstones. Most commonly in critically ill patients. Edematous & enlarged and no gallstones.
3. Fever, leukocytosis, RUQ (a positive murphy’s sign), mild elevations in LFT
   * Caused by anaerobic, gram (-) or select gram (+) infections: start Tx with a 3rd gen. cephalosporin in addition to metronidazole.

Question 560

The presence of odynophagia (eg, pain with swallowing) usually indicates the progression to erosive esophagitis and the formation of an ulcer, which can be confirmed by upper endosocpy.

Question 561

Reducible bulge at umbilicus, notably with increased abdominal pressure in infants.

Answer 561

1. Defect at linea alba covered by skin
2. Associated with: Down syndrome, hypothyroidism, beckwith-wiedemann syndrome.

Question 562

Tx for pyruvate dehydrogenas deficiency:

Answer 562

Ketogenic amino acid metabolism generates the ketone body precursor acetyl-CoA.

• Lysine and Luecine are exclusively ketogenic amino acids; cannot be metabolized to pyruvate and consumption will not lead to increased production of lactic acid.
  *

Question 563

• Myalgias, anorexia, skin rash, macular dermatitis secondary to excessive raw egg whites.

Answer 563

Biotin deficiency that affects:

• Pyruvate carboxyalse: Pyruvate to OAA
• Acetyl-CoA Carboxylase: Acetyl-CoA to Malonyl-CoA (fatty acid synthesis).
• Propinoly-CoA carboxylase.

Question 564

Polyethylene glycol is an osmotic laxative.

Answer 564

Diarrhea associated with lactase deficiency (normal-appearing villi) is also osmotic and occurs due to accumulation of non-absorbable lactose in the intestinal lumen.

Question 565

• Pre-exisiting pituitary adenoma (eg, decreased libido, bitemporal heaminopia)
• The bleeding often presents acutely with severe headache and visual disturbances.
• Panhypopituitarism
• Neuroimaging shows pituitary enlargement & signs of hemorrhage.
  *

Answer 565

Pituitary apoplexy (eg, hemorrhage)

• Cardiovascular collapse due to ACTH deficiency and subsequent adrenocortical insufficiency can develop.

Question 566

Hyperestrinism in liver cirrhosis likely arises due to increases in androstenedione production, androgen aromatization, and SHBG concentration.

Answer 566

Impaired estrogen metabolism by the liver may also be a contributing factor.

A decreased free testosterone/estrogen ratio leads to gynecomastia, testicular atrophy, decreased body hair, and spider angiomata.

Question 567

Patients with UC present with abdominal pain/distension, bloody diarrhea, fever, and signs of shock

Answer 567

Toxic megacolon - plain abdominal X-ray is the preferred diagnostic imaging study.

Question 568

The presence of a fluid-filled cavity in the liver in conjunction with fevers, chills, and RUQ pain is suggestive of:

Answer 568

Hepatic abscess:

• Underdeveloped countries: Entamoeba histolytica, Echinococcal (can rupture, leading to shock; tx with albendazole).
• Developed countries: bacterial (eg, S. aureus via hematogenous seeding of the liver).

Question 569

A 58-year-old female patient presents with a 2-cm firm, fixed, and nontender right axillary lymph node.

Answer 569

1. Typically presents as an irregularly shaped adherent breast mass, most commonly in the upper outer quadrant.
2. Malignant infiltration of suspensory ligaments of the breast causes dimpling of the overlying skins.
3. Annual mammography is the best secondary prevention measure and has been shown to reduce breast cancer mortality rates.

Question 570

Direct invasion of the dermis by a rare type of cancer called inflammatory breast carcinoma can cause skin changes with erythema, and invasion of the lymphatic spaces by malignant cells leads to lymphedema with a finely pitted appearance known as peau d’orange.

Answer 570

Peau d’orange rash:

• Generalized erythematous rash that is often itchy.
  *

Question 571

A prolonged course of TPN is often complicated by gallstones due to:

Answer 571

Absence of normal enteral stimulation in patients receiving TPN leads to decreased CCK release and subsequent biliary stasis.

Question 572

1. UC

• Rectum (always) & colon; continuous lesions.
• T_H-2.
• Only mucosa & submucosa.
• Toxic megacolon ***
• Skin manifestations: erythema nodosum, pyoderma gangrenosum.
• Association: Primary scloersing cholangitis, P-ANCA.

Answer 572

2. Crohn’s disease

• Extending from the mouth to the anus (ileum & colon) & skip lesions.
• Cobblestone appearance.
• Transmural: fistulas & abscesses.
• T_H-1 cells mediate delayed hypersensitivity reactions and noncaseating granuloma formation; also produce IL-2 and IFN-Y and activates macrophages to synthesize TNF.
• Terminal ileum damaged: B12 & Bile Acid reabsorption impaired.
• Diarrhea & Occult bleeding.

Question 573

Hyperthryoid:

• Weight loss despite normal appetite.
• Tachycardia
• Warm, moist skin
• Tremore
• Frightened stare (possible eyelid retraction)
• Can lead to anxiety (esp. in a patient with no prior psychiatric history).

Answer 573

Hypothyroid:

• Fatigability,
• Weight gain
• Myoedema (focal mounding of muscle following percussion) + elevated CK

Question 574

• Infant presents with abdomianl distension + bloody stools.
• Pneumatosis intestinalis (air in the bowel wall) which shows on X-Ray as thin curvilinear areas of lucency that parallel the column.

Answer 574

Affects preterm infants secondry to GI and immunologic immunity: impaired mucosal barrier function allows the bacteria to invade the bowel wall, causing inflammation and ischemic necrosis of the terminal ileum and colon.

Question 575

Curling’s ulcers: arise in the proximal duodenum in association with severe trauma/burns

Pathogenesis: impaired mucosal protection due to local ischemia caused by systemic hypertension and splenic vasoconstriction.

Answer 575

Cushing’s ulcers: intracranial injury –> direct vagus nerve stimulation –> resulting in Ach release and hypersecretion of gastric acid.

Question 576

Phosphorylation of serine and threonine residues of insulin receptor and insulin receptor substrate by serine kinase leads to insulin resistance.

Answer 576

Can be induced by TNF-α, catecholamines, glucocorticoids, and glucagon.

Question 577

Candida albicans

Answer 577

1. Pseudohyphae with blastoconidia
2. Gives rise to true hyphae, termed “germ tubes,” when incubated at 37 for 3 hours
3. Superficial infection: frequently colonizes human skin and mucous membrane (eg, skin, mouth, vagina, and intestine).

• Oral thrush: white patiches form on the oral mucosa in patients who wear denturs, frequently use antibiotics or inhaled steroids.
• Vaginitis: Disruption of vaginal flora (gram-positive lactobacilli) and epithelial injury secondary to antibiotics.

4. Disseminated candidiasis (eg, candidemia, endocarditis)
   * Neutropenic patients.

Question 578

Dietary fructose is phosphorylated in the liver to F1P and is rapidly metabolized because it bypasses PFK-1, the major rate-limiting enzyme of glycolysis.

Question 579

Aspart, lispro, glulisine:

• Alteration of the amino acid structure at the C terminal of the insulin B chain can prevent polymerization and allow rapid absorption from the injection site.
• Postprandial glucose control.

Answer 579

Regular insulin:

• Recombinant human insulin without any amino acid modification; used subcutaneously in the long-term managmenet; initial treatment for DKA.
• Starts working within 30 minutes, peaks in 2-4 hours, and lasts 5-8 hours.

Glargine & Determir: a long-acting insulin analogue that last up to 24 hours (basal-line).

Question 580

Grave’s disease Tx

Answer 580

1. Antithyroid drugs (thioamides): Inhibits TPO, impairing iodine organification.

• Agranulocytosis (fever, sore throat).
• Methimazole: 1st-trimester teratogen.
• PTU: Hepatic failure; can decrease peripheral conversion of T4 to T3.

2. Pertechnetate/perchlorate: inhibits iodine reuptake.
3. B-B: Decreases peripheral conversion of T4 to T3 by inhibiting iodothyronine deiodinase.

Question 581

Cortisol increases conversion of Norepinephrine to Epinephrine by upregulating PNMT

Answer 581

Pituitary resection –> decreased ACTH –> decreased cortisol would decrease Epi production.

Question 582

• Paraneoplastic hyperthyroidism (eg, weight loss, sweating, heat intolerance).
• Ovarian/testicular malignancy.

Answer 582

• Significantly increased B-hCG levels.
  
  • May produce symptoms of hyperthyroidism (hCG is structurally smiilar to LH, FSH, TSH).
• Hematogenous spread, esp. to lung: patient can present with SOB & hemoptysis following pregnancy.
• Composed of abnormal proliferation of cytotrophoblasts & synctiotrophoblast
  
  • Absent villi.

Question 583

Decrease in vitamin D: rickets in children & osteomalacia in adults

Answer 583

Low levels of 1,25-dihydroxyvitamin D (calcitriol)

Question 584

Bilious vomiting after feeding and a palpable ball of muscle (“olive”) in the abdomen:

• Pyloric stenosis.

Answer 584

Presents with bilious vomiting and abdominal distension within first 1-2 days of life:

• Duodenal atresia: failure to recanalize. Associated with “double bubble” (dilated stomach, proximal duodenum)
• Jejunal and ileal atresia: vascular occlusion in utero –> diminished intestinal perfusion leads to ischemia of a segment of bowels.

Question 585

Diphenoxylate & loperamide

Answer 585

Binds mu opiate receptors and slows motility.

Question 586

nf-kB pathway

Answer 586

Nf-kB is a transcription factor with a critical role in the immune response to infection by increasing cytokine production. Normally present in the cytoplasm in a latent, inactive state bound to its inhibitor protein, IkB.

Extracellular substances such as LPS can initiate a signal cascade that results in the destruction of IkB and translocation of free NF-kB to the nucleus.

Question 587

Complications:

• Pseudocyst (lined by granulation tissue)
• ARDS (hyaline membrane in alveolar septate).
• After gallstones, alcohol abuse is the second most common cause
  
  • AST:ALT > 2 + Macrocytosis (folate deficiency).
• Fat Necrosis: Formation of fatty acids that bind calcium ions and precipitate as insoluble calcium salts.

Question 588

The ureters pass posterior to the ovarian (gonadal) vessels within the retroperitoneum and anterior to the common/external iliac arteries to reach true pelvis.

• Within the true pelvis, the ureters lie anterior to the internal iliac artery and medial to the ovarian vessels (branch of gonadal vessels).

Answer 588

The uterine artery crosses over the anterior surface of the ureter (“water under the bridge”).

• Hysterectomy.

Question 589

Exogenous T3 supplementation would suppress TSH levels by increasing negative feedback, which in turn would decrease T4 secretion from the thryoid gland.

Answer 589

Furthermore, rT3 would also decrease because less T4 would be available for conversion (T3 cannot be converted into rT3).

Question 590

Strongyloides stercoralis: diagnosis by finding rhabditiform (noninfectious) larvae in the stool.

Answer 590

• Larvae penetration through the exposed skin of feet
• Eosinophilia and GI disease in immuno-competent individuals or hyper-infection in immunocompromised patients.
• Tx: Ivermectin.

Question 591

An athelete should be suspected of abusing androgens/steroid:

Answer 591

• Acne ***
• Testicular atrophy
• Erythrocytosis
  
  • Testosterone stimulates RBC production (increased hematocrit)

Question 592

Dubin-Johnson syndrome

Answer 592

Grossly, the liver appears black due to impaired excretion of epinephrine metabolites that acumulate within lysosomes.

Question 593

1. Stress:

• Decreased urethral sphincter tone: pelvic floor muscles (levator ani, coccygeus) function with the urethral valve to maintain continence.
• Urethral hypermobility
• Symptoms: leakage with coughing, lifting, sneezing.
• Causes: Intraabdominal pressure (eg. pregnancy) that exceed the pressure point of the sphincter.

Answer 593

2. Urge:

• Destrusor hyperactivity: “overactive bladder”: Multiple sclerosis.
• Sudden, overwhelming urge to urinate.
• Tx: Oxybutynin.Tolterodine an antimuscarinic agent.

3. Overflow:

• Impaired detrusor contractility: diabetic autonomic neuropathy & post-op.
• Bladder outlet obstruction —> Increased postvoid residual volume.
• Tx: Bethanechol.

Question 594

• Pain decreases with meals.
• 90% are associated with H.pylori: Eradicate with triple therapy (2 antibiotics + PPI)
• H.pylori: Chronic antral inflammation(gastritis) leads to decrease in the number of somatostain-producing cells (delta cells) –> increased gastrin release overwhelms duodenal bicarbonate production–> duodenal ulceration.

Answer 594

• Very rarely malignant vs. gastric ulcers (MALT, gastric adenocarcinoma)

Question 595

In hyperglycemic states, aldose reductase converts glucose to sorbital at a rate faster than sorbitol can be metabolized. Sorbitol accumulates in certain cells such as lens cells, causing an influx of water (cataract) and resulting in osmotic cellular injury.

Question 596

F2,6BP

• Activates PFK-1 (increasing glycolysis)
• Inhibits fructose 1,6-bisphophatase
  
  • Decreasing gluconeogenesis. eg) alanine—> glucose.

Question 597

The live attenuated oral (sabin) poliovirus vaccine produces a stronger mucosal secretory IgA immune response than does the inactivated poliovirus (salk) vaccine.

Answer 597

Mucosal IgA: inhibits viral entry by inhibiting attachment to intestinal epithelial cells

• IgA protease produced by N. gonorrhoeae, N. meningitidis, S. pneumoniae, H. influenzae: facilitates mucosal adherence.

Question 598

Insulin:Pl3K promotes glycogen synthesis by activating protein phosphatase (inactivating glycogen phosphorylase).

Answer 598

Glucagon & Ca²⁺ from (striated) muscle contraction:

• PKA activates glycogen phosphorylase via activation of glycogen phosphorylase kinase —> glyconeolysis.

Question 599

Tight junctions: Claudins, Occludin

• BBB

Gap junctions: Connexins; Intercellular communication

• Myocytes.
• Osteocytes.

Answer 599

Desmosome: Desmoglein (keratin intermediate filament interactions).

• Pemphigus vulgaris

Hemidesmosomes: Integrins.

• Bullous pemphigoid.

Question 600

Severe hypoglycemia with loss of consciousness is typically treated with intramuscular glucagon in the non medical setting and with IV dextrose in the medical setting.

Answer 600

Buccal/sublingual/oral glucose or sucrose may be attempted, but absorption is slow and erratic and may be ineffective (especially if patient is unconscious due to risk of aspiration)

Question 601

Tx for hepatic encephalopathy

Answer 601

Lactulose: lowers colonic pH and increase conversion of ammonia to ammonium.

Rifaximin: a non absorbable antibiotic that stimulates GI flora to decrease intestinal production and absorption of ammonia.

Question 602

Hypoketotic hypoglycemia after a period of fasting:

• Low glucose
• Undetectable serum acetoacetate.

Answer 602

Defect in fatty acid B-oxidation;

• Acyl-CoA dehydrogenase deficiency mutation.
• Normal B-oxidation generates FADH₂ and NADH for ATP production & acetyl-CoA for TCA & ketogenesis.

Question 603

HSV2

Answer 603

1. Presents with:

• Fever, myalgia
• Inguinal lymphadenopathy
• Itchy, painful, vesicular genital rash.

2. Lies dormant in the sacral DRG and can be reactivated to cause recurrent genital lesions.

Question 604

Cavernous hemangioma?

Answer 604

Common vascular malformations that frequently involve the deeper tissues of the body, such as the liver and brain.

• “Mulberry-like” appearance due to their purple vascular clusters:
• cavernous, blood-filled vascular spaces of variable size lined by a single epithelial layer: most common benign liver tumor.
• Can cause intracerebral hemorrhage.

Question 605

Trypsinogen: converted to active enzyme trypsin.

• Activation of other proenzyems and cleaving of additional trypsinogen molecules into active trypsin.
• Implicated in (acute) pancreatitis.

Answer 605

Cleaved by enterokinase/enteropeptiase, a brush-border enzyme of duodenal and jejunal mucosa.

Question 606

Commonly presents as bilious emesis during the first days of life.

Answer 606

Intestinal malrotation results when the midgut undergoes incomplete embryological CCW rotation:

• It can present as intestinal obstruction (due to compression by the adhesive bands) and midgut volvulus (intestinal ischemial due to twisting around the blood vessels).

Question 607

Which cytokines are chemotactic agents?

Answer 607

• LTB₄
• C5a
• IL-8
• 5-HETE
• n-formylated peptides

Question 608

• Polyhydramnios due to inability to swallow amniotic fluid.
• Significant drooling (due to inaibltiy to swallow saliva).
• Choking, coughing, and cyanosis with feeds (due to refulx of breastmilk/formula and aspration into the trachea/lungs).
• Stomach bubble.

Question 609

Portosystemic anastomes due to cirrhosis

Answer 609

Esophageal varices: Left gastric vein <–> Esophageal vein

Caput medusae: Paraumbilical veins <–> Superficial & inferior epigastric veins.

Anorectal varices: Superior rectal vein <–> Middle & inferior rectal veins

Splenic vein drains blood from the spleen; joins with the superior mesentrie vein to form the hepatic portal vein;

• Patients with portal HTN can develop splenomegaly due to congestion of the splenic red pulp.

Question 610

Most important risk factor for HPV?

Answer 610

sexually transmitted infections,

High-risk strains (16,18,31): E6 binds protein p53 and increases its degradation, whereas E7 binds to the Rb1 and displaces transcription factors normally bound by pRB.

Question 611

Sex steroids initially increased linear growth, but they also encourage closure of epiphyseal growth plates; hence if this patient isn’t treated, she will ultimately not meet her full growth potential.

Answer 611

An increase in estrogen activity (e.g., pregnancy, COP, post-menopausal hormone replacement therapy) raises circulating TBG levels –> an increase in TBG levels leads to an increase in total T4 as well as total T3.

However, the level of free thyroid hormones remains normal, patient remains euthyroid, and TSH levels remain n the normal range.

Question 612

Metformin

Answer 612

MOA: inhibits the mitochondrial enzymes required for gluuocogenesis; increases peripheral glucose uptake

ADR: lactic acidosis.

Question 613

Short bowel syndrome:

Answer 613

Extensive intestinal disease or resection results in loss of absorptive surface area and a decrease in intestinal transit time, leading to postprandial voluminous diarrhea and weight loss due to malabsorption of macro-and micronutrients.

Question 614

Hepatic encephalopathy:

• GI bleeding causes increased nitrogen delivery to the gut in the form of hemoglobin, which is then converted into ammonia and absrobed into the bloodstream.

Answer 614

1. Astrocytes take up glutamate present in the synpase, preventing excessive neuronal excitation.

2. Gltuamine synthetase condenses glutamate with ammonia to form glutamine.

3. Glutamine is released by astrocytes and taken up by neurons, where it’s converted back to glutamate for use as a neurotransmitter.

4. Excess glutamine –> impaired glutamien release from astrocyte –> disruption of excitatory neurotransmitters & increased inhibitory NTs.

Question 615

Developmental delay and/or regression, hypotonia, optic atrophy, and seizures.

Answer 615

Krabbe disease:

• Galactocerebrosidase deficiency causes accumulation of galactocerebroside and psychosine.

Question 616

Gallstone ileus:

Answer 616

A mechanical bowel obstruction caused when a large gallstone erodes into the intestinal lumen through a cholecystoenteric fistula.

• Usually lodged at ileocecal vale.
• Small bowel obstruction: abdominal distension, tenderness, and high-pitched bowel sounds.
• Penumobilia (air in the biliary tract) is a common finding.

Question 617

Kallman syndrome:

Answer 617

An absence of GnRH secretion neurons in the hypothalamus due to defective migration from the olfactory placode.:

Central hypogonadism and anosmia, and often present with delayed puberty.

Question 618

The secretory phase of the menstrual cycle occurs between ovulation and menses, from days 15-28 of the normal menstrual cycle.

Answer 618

Progesterone (highest concentration following ovulation) released by the corpuse luteum causes the uterine glands to coil and secrete glycogen-rich mucous in preparation for embryo implantation.

The endometrial storma becomes edematous and completely traversed by tortuous spiral arteries that extend from the deeper layers to the uterine lumen.

Question 619

Effects of prolonged glucocorticoid therapy?

Answer 619

• Adipose: Lipolysis, altered fat distribution
• Adrenal cortex: Atrophy
• Bone: Pathologic osteoporosis
• Immune system: Suppression of T cell apoptosis & Neutrophilia
• Liver: Increased gluconeogenesis & glycogenolysis (diabetes)
• Skin: thining striae/impaired wound healings.

Question 620

Systemic mastocytosis

Answer 620

1. Mast cell proliferation associated with mutations in the KIT receptor tyrosine kinase.
   * Tryptase.
2. Excessive histamine release from degranulation of mast cells mediates many of the symptoms of the disease, such as syncope, flushing, hypotension, pruritus, and urticaria.
3. In addition, histamine induces gastric acid secretion, which can lead to gastic ulcertaiotn.

Question 621

Scleroderma: triad of autoimmunity, noninflammaotyr vasculopathy, and collagen deposition with fibrosis

Answer 621

Limited scleroderma: Limited skin involvement confined to fingers and face:

• Calcinosis & anti-Centromere antibody.
• Raynaud phenomenon
• Esophageal dysmotility: atrophy and fibrosis replacement of the muscularis in the lower esophagus
• Sclerodactyly
• Telangiectasia
• Pulmonary artery HTN can cause cor pulmonale and symptoms of right-sided heart failure (lower extremity edema and hepatomegaly).

Question 622

The patient is suffering from perforated appendicitis that has evolved into an intraabdominal abscess.

Answer 622

B. fragilis is a common anaerobic gram-negative bacillus that’s frequently isolated from intraabdominal abscesses.

Question 623

Coronary heart disease is the most common cause of death in patients with DM

Question 624

Hypercalcemiae:

• Mental status changes
• Muscle weakness
• Constipation
• Polyuria/polydipsia

Answer 624

1. Vitamin D intoxication
2. Activated macrophages in sarcoidosis and other granulomatous diseases express 1-a-hydroxylase, leading to the production of excess 1,25-dihydroxyvitamin D and hypercalcemia.

Question 625

• Necrolytic migratory erythema
• Erythematous papules/plaques on face, perineum & extremities
• Lesions enlarge & coalesce, leaving a central indurated area with peripheal blistering & scaling
• DM/hyperglycemiae
• GI symtpoms (diarrhea, anorexia, abdominal pain)

Question 626

Diverticulitis

Answer 626

Inflammation of saclike protrusions that typically form in the sigmoid colon of older patients:

• LLQ,
• Diarrhea & constipation
• Low-grade fever
• Fistulas
• Usually in older ages.

Question 627

Arsenic poisoning

Answer 627

1. Toxicity: exposure to pesticides/insecticides, contaminated water, pressure-treated wood, metallurgy, mining, or glass-making.
2. Acute presentation: garlic breath, vomiting, watery diarrhea, QTc prolongation
3. Tx: Dimercaprol (chelating agents that increases urinary excretion of heavy metals).

Question 628

Which supplementation is necessary following gastrojejunostomy?

Answer 628

Iron; its absorption occurs predominantlely in the duodenum and proximal jejunum.s

Question 629

Complete molar pregnancy:

• 46, XX > 46, XY
• No fetal structures; composed entirely of large, edematous, and disordered chorionic villi that appears grossly as clusters of vesicular structures (bunch of grapes).

Question 630

Insulin release by pancreatic B-cells (GLUT2) is stimulated by increased ATP production.

Answer 630

Glucokinase functions as a glucose sensor in pancreatic beta cells by controlling the rate of glucose entry into the glycolytic pathway.

• Mutations in the glucokinase gene are a cause of MODY.

Question 631

GTP is synthesized by succinyl-CoA synthetase during the conversion of succinyl-CoA to succinate in the TCA.

Answer 631

During gluconeogensis, PEPCK uses GTP to synthesize PEP from oxaloacetate.

Question 632

Cytosolic acetyl-CoA carboxylase converts acetyl-CoA to malonyl-CoA during the rate-limiting step of de novo fatty acid synthesis.

Answer 632

Malonyl-CoA inhibits the action of mitochondrial carnitine acyltransferase, thereby inhibiting beta-oxidation of newly formed FAs.

Question 633

Testicular torsion

• Gonadal artery affected (branches off of AA)

Answer 633

Ovarian torsion:

• Ovary receives it blood supply through the vessels that transverse the infundibulopelvic (IP ligament) eg, suspensory ligament of the ovary.

Question 634

The patient presents with abdominal pain and bloody diarrhea following a complicated surgical procedure

Answer 634

Ischemic colitis:

• “watershed” areas (eg, splenic flexure and rectosigmoid junction) are susceptible to ischemic damage during hypotensive states, especially in patients with underlying arterial insufficiency.
• The colon receives blood from the marginal artery of the colon (Drummond), an anastomotic system of arteries that is in turn supplied by SMA and IMA.

Question 635

Majority of acute pancreatitis cases are caused by gallstones and chronic alcoholism.

Answer 635

Less common causes account for other 20%:

• Inherited or acquired hypertriglyceridemai > 1000mg /dL.

Question 636

A blind pouch connected to the ileum, with a fibrous band seen ataching the end of the pouch to the umbilicus

Answer 636

Meckel’s diverticulum: failure of obliteration of the vitelline (or omphalomesenteric duct).

• True diverticulum (Mucosa, submucosa, and muscular layers).
• 2% of the population; 2 feet from the ileocecal valve, 2 inches in length, 2% are symptomatic, males are 2 times more likely, 2 years old.
• Two ectopic tissues (gastric/pancreatic): can cause painless lower GI bleeding (eg, dark red blood on toilet tissues).
• Diagnosis; Increased Tc-pertechnetate in the RLQ.

Question 637

Progesterone withdrawal

Answer 637

Causes increased secretoin of metalloproteases by endometrial stromal cells (causing degradation of the ECM) and apoptosis of the endometrail epithelium.

The net effect is degeneratoin of the functionalis layer, which sloughes away as menstraul flow.

Question 638

• Intermittent solid/liquid dysphagia, chest pain, heartburn, food regurgitation.
• Periodic, simultaneous, and non-peristaltic contractions of large amplitude and long duration.
• Likely involves impaired inhibitory neurotransmission within the esophageal myenteric plexus.

Question 639

Septic abortion

Answer 639

1. Pregnancy termination with infected retained products of conception in the uterine cavity.
2. Typically presents with fever, abdominal pain, uterine tenderness, and/or a foul-smelling vaginal discharge.
   * Boggy & tender uterus with dilated cervix.
3. S. aureus & gram(-) bacilli
4. Complications: adhesions in the uterine cavity that can lead to secondary amenorrhea and infertility (Asherman syndrome).

Question 640

SGLT2 inhibitors: Canaglioflozin, dapagliofolzin

Answer 640

1. Decrease PCT reabsorption of glucose, thereby promoting urinary glucose loss.
2. Monitor kidney function before/after initiating therapy.

Question 641

Vitamin A deficiency vs. excess?

Answer 641

1. Deficiency:

• Night blindness
• Severe eye dryness & corneal ulceration
• Hyperkeratosis: Responsible for orderly differentiation of specialized epithelial.
• Growth retardation.

2. Vitamin A excess:
   * Intracranial HTN, skin changes and hepatosplenomegaly.

Question 642

Injury to the posterior urethra is associated with pelvic fractures, and the anterior urethra is the most commonly damaged in straddle injuries. Inability to void with a full bladder sensation, a high-riding boggy prostate, and blood at the urethral meatus are suggestive of urethral injury.

Answer 642

In contrast to prostatic and bulbous segments, the membranous segment is relatively unsupported by the adjacent tissues and is the weakest point of the posterior urethra. Trauma to the pelvic severe enough to cause fracture often results in disruption of posterior urethra at the bulbomembranous junctions.

Question 643

Riboflavin is a precursor of the coenzymes FMN and FAD. FAD participates as an electron acceptor for SCDH (complex II), which participates in both lectron transport chain and TCA cycle.

Answer 643

Clinical manifestations:

• Angular stomatitis
• Cheilitis
• Glossitis
• Seobrrheic dermatitis
• Eye changes (eg, keratitis, corneal neovascularization)
• Anemiae.

Question 644

Sertoli-Leydig ovarian tumor

Answer 644

Increased androgens leading to virilization (e.g., hirsutism, clitoromegaly, deeper voice).

Question 645

Biopsy of gonadal tissue shows a lack of sertoli cells but normally functioning Leydig cells. Which phenotype would most likely be present?

Answer 645

Internal reproductive organs: Female and Male

External genitalia: Male.

Question 646

After vasectomy, viable sperm remain in the portion of the vas deferense distal to ligation for at least 3 months.

Question 647

Patient’s postprandial epigastric pain and associated food aversion/weight loss in the setting of generalized atherosclerosis (e.g., CABG, carotid endarterectomy) is consistent with?

Answer 647

Chronic mesenteric ischemia ~ analogus to stable cardiac angina.

Question 648

Mifepristone:

• Progesterone antagonist
• Apopotosis and necrosis of the uterine decidua and prevents further development of a first trimester pregnancy.

Answer 648

Misoprostol

• Used to prevent NSAID-induced peptic ulcers.
• Also used off-lable for induction of labor: contraindicated during pregnancy.

Question 649

• GI hemorrhage that manifests as painful hematemesis.
• Longitudinal mucosa tears at the esophagogastric-squamocolumnar junction.

Answer 649

• Tears occur secondary to rapid increase of intraabdominal and intraluminal gastric pressure, as when happens during retching and vomiting (metabolic alkalosis).
• Risk of Boerhaave syndrome.

Question 650

Dx?

Answer 650

Abetalipoproteinemia: a disease caused by impaired formation of apoB-containing lipoproteins:

• Enterocytes contain clear or foamy cytoplasm.
• Manifests during the first year of life with symptoms of malabsorption (abdomianl distension, foul-smelling stool)
• Very low plasma TG & cholesterol levels; chylomicrons, VLDLs, an apoB are entirely absent from the blood.

Question 651

Chronic alcoholic pancreatitis

Answer 651

Diarrhea, weight loss, and epigastric calcifications in a patient with chronic alcoholism suggest chronic pancreatitis with resulting panacratic exocrine insufficiency and malabsorption.

Question 652

Cholelithiasis

Answer 652

• Increased cholesterol.
• Decreased bile acids & phosphatidylcholine.
• Estrogen-induced cholesterol hypersecretion and progesterone-induced gallbladder hypomotility.

Question 653

D₂ antagonism.

Answer 653

1. Extrapyramidal side effects:

• Acute dystonic reaction (e.g., spasmodic torticollis): sudden-onset, sustained muscle contractions.
• Akathisia: subjective restlessness with inability to sit still.
• Drug-induced parkinsonism: prominent rigidity & bradykinesia (slowed movement, decreased arm swing); tremor (rest & postural), masked facies
  
  • Tx: Decrease or discontinue offneding medication.
  • Anticholinergics (trihexypenidyl, benztropine)

2. Tardive dyskinesia:

• Involuntary movements after chronic use (lip smacking, choreoathetoid movements).
• Upregulation & compensatory supersensitivity of postsynaptic dopamine receptors.

Question 654

Transference: usually from a patient to a physician.

Answer 654

1. Displacement:
2. Passive aggression: avoiding conflict by expressing hostility covertly.s

3. Projection: Attributing one’s own feelings to others.

4. Reaction formation: redirection of an unacceptable feelings to its extreme opposite.
5. Sublimation: a mature defense mechansim that invovles challenign an unacceptable impsule into an socially acceptable form of behaviour.
6. Suppression: a mature defense mechanism in which an indivdiual intentionally puts aside unpleasant thoughts or feelings to better cope with the present reality (vs. repression: unacceptable thougths or feelings are blocked from entering consciouss awareness).

Question 655

A patient presents with chest pain, palpitations, shortness of breath, and sweating. He has been to the ED twice in the past month for similar symptoms. His PMH is otherwise noncontributory and ECG normal. The patient is tremulous and says, “I feel like I’m going to die”.

Answer 655

Panic Disorder

• Immediate: Benzodiazepine
• Long-term: SSRI/SNRI/CBT

Question 656

Dx & complications?

Answer 656

Porcelain gallbaldder - increased risk for gallbladder adenocarcinoma.s

Question 657

Tourette disorder

Answer 657

Both multiple motor & > 1 vocal tics:

• Motor: Facial grimacing, blinking, head/neck jerking, shoulder shrugging, tongue protrusion, sniffling
• Vocal: grunts, snorts, throat clearing, barking, yelling coprolalia

Tx:

• Antipsythoics
• a-2 aderenergic receptor agonists.

Question 658

Low potency:

• Chlorpromazine
• Thioridazine
• ADR: Sedation (histaminergic blockage), Anticholinergic side effects (cholinergic blockade), Orthostatic hypotension (alpha-1 adrenergic blockade)

Answer 658

High-potency FGA:

• Haloperidol
• Fluphenazine
• Can be used for the acute treatment of agitation and psychosis associated with delirium.
• ADR: Extrapyramidal symptoms: Acute dystonia, akathisia, Parkinsonissm

Prochlorperazine, a typical antipsychotic agent that’s more often used for its antiemetic properties, functions at D₂ in CTZ.

Question 659

Valproic acid: anti-convulsant mood stabilizer.

Answer 659

1. MOA:

• Na+ channel blocker; inhibitis GABA transaminase
• Bipolar disorder
• Commonly used for seizure prophlyaxis: absence, myoclonic, generalized tonic-cloinc seizures.

2. ADRs: hepatotoxicity (measure LFT); neural tube defects, weight gain.
3. Others include carbamazepine and lamotrigine.

Question 660

Second-generation antipsychotics: Less affinity for D2 receptors and the additional property of serotonin 5HT2 receptor antagonism (lower risk of extrapyramidal side effects).

Answer 660

• Olanzapine: Weight gain, increased risk of metabolic syndrome (dyslipidemia, HTN, hyperglycemiae); adjunctive Tx to psychotherapy for anorexia nervosa.
• Clozapine: a second-generation antipsychotic indicated for tratment-refractory schizophrenia; agranulocytosis.
• Risperidone

Question 661

• Acute: a prodrome of fever, malaise, anorexia, N/V, RUQ tenderness.
• Several days: Cholestasis, including jaundice, pruritus, dark-colored urine, and acholic stool (due to increased conjugated bilirubin levels).
• Travel to South America.

Answer 661

Acute viral hepatitis is characterized histologically by the presence of “spotty necrosis” with ballooning degeneration (hepatocyte swelling with wispy/clear cytoplasm), councilman bodies (eosinophilic apoptotic hepatocytes) and mononuclear cell infiltrates.

Question 662

Buspirone

Answer 662

1. Nonbenzodiazepine anxiolytic

• Slow onset of action.
• No risks of tolerance, dependence, or withdrawal.

2. Partial agonist of the 5HT_1A receptor.
3. No muscle relaxant or anticonvulsant properties.

Question 663

2nd brachial arch:

• Reichert cartilage: stapes, styloid process, lesser horn of hyoid, stylohyoid ligament
• Muscles of facial expression, stapedius, stylohyoid, plastysma, posterior belly of digastric
• CN VII
• Tracher-Collins syndrome: Abnormal development of the first and second pharyngeal arches; neural crst dysfunciton –> mandibular hypoplasia, facial abnormalities.

Answer 663

3rd brachial arch:

• Greater horn of hyoid
• Stylopharyngues - innervated by CN IX

Question 664

Imperforate hymen:

*

Answer 664

• Incomplete degeneration of the central portion of the fibrous tissue band connecting the walls of the vagina.
• Adolescents typically present with primary amenorrhea, normal secondary sexual characteristics, and cyclic abdominal or pelvic pain due to accumulation of menstraul blood in the vagina & uterus (hematocolpos)

Question 665

Autism Spectrum disorder:

Answer 665

1. Multiple, persistent deficits in social communication & interactions currently or by history.
2. Restricted, repetitive patterns of behaviour currently or by history.
3. Language impairment.
4. More common in boys & symptoms are typically recognized by age 2.

Question 666

Premature ejaculation:

Answer 666

Unwanted episodes of early ejaculation (within 1 minutes of penetration, most of the time for at least 6 months) accompanied by a sense of lack of control.

Question 667

Alpha-1 antitrypsin deficiency:

• Unregulated activity of neutrophil elastase.
• Panacinar emphysema (prolonged expiration with scattered bilateral wheezes/ hyperlucency of lung fields and flattening of diaphragm)
  
  • PMH of liver cirrhosis.
  • FMH of lung & liver cancer.
  • Minimal personal tobacco history.
• Affects predominantely lower lobes (due to realtively greater perfusion, allowing a grearter rate of neutrophil infiltration).

Question 668

During prolonged fasting:

Answer 668

1. Glucagon is the primary hormone secreted in response to a rapid drop in blood glucose levels, with epinephrine acting as the backup(acute): G_s
   * glycogenolysis occurs within first 12-24 hours; gluconeogensis predominant after.
2. Cortisol (more chronic): binds to an intracellular receptor & glucogenesis/lipolysis/proteolysis.

Question 669

Manic episode:

• > 1 weeks of elevated or irritable mood & increased energy/activity
• > 3 of the following symptoms (4 if mood is irritable only):
  
  • Distractibility
  • Impulsivity
  • Grandiosity
  • Flight of ideas/racing thoughts
  • Increased activity/psychomotor agitation
  • Decreased need for sleep
  • Talkativeness/pressured speech.
• Can occur with or without psychotic features (eg, delusions hallucinations).
• Patients with one or more lifetime manic episodes are diagnosed with bipolar I disorder; depressive episodes are not required for diagnosis.

Answer 669

Bipolar II disorder:

• Hypomania: a lesser degree of severity and funcitonal impairtment and absence of psychosis.
  
  • Often very productive in work; rarely hospitalized.
• > 1 major depressive episodes required.

Cyclothymic disorder:

• > 2 years of numerous periods of hypomanic and depressive symptoms.

Question 670

Trazodone:

Answer 670

• A sedating antidepressant most often used as a hypnotic to treat insomnia associated with depression or antidepressnt treatment.
• Serotonin modulator (antagonizes postsynaptic 5-HT₂ and inhibits serotonin reuptake).
• Priapism (persistent erection of the penis for >4 hours and not associated with sexual excitement).

Question 671

SSRI: Fluoxetine, fluvoxamine, paroxetine, sertraline, escitalopram, citalopram

SNRI: Venlafaxine, desvenlafaxine, duloxetine.

Answer 671

ADRs:

• Sexual side effects (decreased libido, anorgasmia, delayed ejaculation).
• can precipitate manic episodes in pts. with bipolar disorder.

Question 672

Schizophrenia:

Answer 672

1. Brief psychotic disorder lasts < 1 month; return to fully normal.
2. Schizophreniform disorder:
   * >1 months but <6 months
3. Schizophrenia:

• >6 months.
• Delusions, hallucinations, disorganized speech (loosening of associations, nonsensical words).
• Grossly disorganized behaviour (unpredictable agitation, bizzare behaviours, inappropriate affect), negative symptoms (affective flattening, anhedonia, asociality).

Question 673

Learning disorder:

• Difficulties with learning key academic skills (reading, writing, mathematics).
• Manifest at school age when these skills are being acquired and performance is well below average for age (“behind the other kids in his class”)
• Display symptoms of anxiety, inattention, or hyperactivity when under stress to perform in an area of weakness.

Question 674

Social anxiety disorder:

• Marked anxiety about >1 social situations for >6 months.
• Fear of scrutiny by other, humiliation, embarrassment.
• Social situations avoided or endured with intense distress.
• Marked impairment: social, academic, occupational.
• Tx: SSRI/SNRI, CBT
• Subtype specifier: performance only
  
  • Tx: BB & benzodiazepine

Answer 674

Normal adolescence:

• Intense self-consciousness
• Concerns about appearance and social acceptance (vs. social anxiety disorder)
• Moodiness.
• Increasing need for privacy.
• Transient emotional outbursts

Question 675

The optic tract contains nerve fibers from the temporal part of the ipsilateral retina and the nasal part of the contralateral retina. ***

Answer 675

1. Right nasal hemianopia:

• Right nasal information transferred to right temporal hemi-retina –> Right peri-chiasmal lesion.
• Calcification or aneurysm of the internal carotid artery impinging on uncrossed, lateral retinal fibers.

2. Right temporal lobe lesion (Meyer’s Loop):

• Left homonymous superior quadrantanopia (“pie in the sky”).
• • Aphasia (dominant hemisphere lesions), memory deficits, seizures (complex partial and tonic-clonic), hallucinations (auditory, olfactory, and visual).

Question 676

Delusional disorder:

Answer 676

• > 1 delusions (persistent, overriding, fixed beliefs) for > 1 months
• Other psychotic symptoms absent or not prominent
• Ability to function apart from delusion; behaviour not obviously bizzare or odd (eg, stable employment).
• Subtype:
  
  • Erotomanic: someone is in love with them.
  • Grandiose: believing they have greater talent, insights, or achievements.
  • Jealous: believing their partner is unfaithful.
  • Persecutory: believing they’re being cheated, spied on, poisoned
  • Somatic

Question 677

Benzodiazepines: anxiety, insomnia, acute seizures, alcohol withdrawal.

1. Short: Triazolam, oxazepam, midazolam.
2. Intermediate: Alprazolam, lorazepam, temazepam.
3. Long: Chlordiazepoxide, diazepam, flurazepam.

Short & intermediate best suited for minimal undersirable daytime side effects (fatigue, impaired judgment).

Answer 677

Zolpidem: nonbenzodiazepine used for insomnia with less anxiolytic effect.

• Less potential for tolerance and addiction
• No anticonvulsant properties in regular doses
• No muscle relaxing effects and not used for anesthesia.

Question 678

Major depressive disorder:

• Lasting > 2 weeks
• >5 of the following 9 symptoms (at least 1 symptoms is either depressed mood or loss of interest or pleasure)
  
  • Depressed mood *
  • Loss of interest or pleasure
  • Change in appetite or weight
  • Insomnia or hypersomnia
  • Psychomotor retardation or agitation
  • Low energy
  • Poor concentration or indecisiveness
  • Thoughts of worthlessness or inapporpriate guilt
  • Recurrent thougths of death or suicide.
• No history of mania or hypomania (rule out bipolar disorders)
• Not due to substances or another medical condition.

Answer 678

• Pure dysthmia & chronic major depression:
• Depressive symptoms have lasted >2 years.

Question 679

B-hCG typically is detectable in the maternal serum approximatley 8 days after fertilization & detectable in the urine 14 days after fertilization.

• Secreted by the embryonic synctiotrophoblast during the 1st trimester, rising to its highest levels at the 9 weeks of gestation.
• Serves to maintain the corpus luteum until the placenta can assume responsbility for estrogen and progesteone synthesis.
• Drop in progesterone after delivery disinhibits prolactin secretion.

Answer 679

hPL: Increased insulin resistance, to shunt carbohydrate toward the fetus.

Question 680

• Primary hypogonadism.
• Gynecomastia
• Sparse facial/body hair.
• Learning & socialization difficulties.

Answer 680

Increased LH, FSH:

• Serum inhibin levels are decreased as a result of the Sertoli cell damage.
  
  • Small, firm testes.
• Leydig cells are usually dysfunctional as well, resulting in reduced testoserone levels.
• Patients can develop high estrogen levels and gynecomastia due to increased aromatase acitvity (stimulated by gonadotropin excess).

Question 681

Increased MSAFP:

• Open neural tube defects (e.g., anencephaly, open spina bifida)
  
  • Also may see AchE.
• Ventral wall defects (omphalocele, gastroschisis)
• Multiple gestations

Answer 681

Decreased MSAFP

• Aneuploidies (trisomy 18 & 21).
• Date error ???

Question 682

Congenital torticollis:

• 2-4 weeks of age, after which the child prefers to hold the head tilted to one side.
• It’s most commonly the result of malposition of the head in utero or bith trauma.
  *

Question 683

Subacute granulomatous thyroiditis (de Quervain thyroidits)

• Typically follows an acute viral illness
• Tender.
• A transient hyperthryoid phase due to release of stored thyroid hormone; T4, suppressed TSH, decreased radioiodine uptake.
• Lymphocytic infiltrate with macrophages & multinucleated giant cells.

Answer 683

Reidel

• Extensive fibrosis of the thyroid gland that extends into the surrounding tissues
• Thyroid gland is hard and non-tender.

Question 684

Rotator cuff muscles

Answer 684

1. Supraspinatus

• Abduction
• Suprascapular nerve
• “Empty can test” ***

2. Infraspinatus

• External rotation
• Suprascapular nerve

3. Teres minor

• Adduction & external rotation
• Aaxillary nerve: Axillary nerve damaged from anterior dislocations of the humerus (also supplies deltoid).

4. Subscapularis:

• Adduction & internal rotation
• Upper & lower subscapular nerve.

Question 685

Osteogenesis imperfecta: defective synthesis of type 1 collagen (predominant cartilage in osteoid) by osteoblasts.

Answer 685

• Blue-tinged sclera, due to underlying choroidal vessels showing through thin sclerae.
• Small, malformed teeth (dentinogenesis imperfecta).
• Brittle bones that are prone to fracture.

DDx for child abuse suspicion.

Question 686

Tetrodotoxin (puffer fish; Japanese delicacy) & Saxitoxin:

Answer 686

Binds to Na+ channels, inhibiting Na+ flux and preventing actionl potential conduction.

Question 687

Methylmalonic acidemia:

• Organic acidemia due to complete or partial deficiency of methylmalonyl-CoA mutase.

Answer 687

• Complete deficiency classically presents with lethargy, vomiting, and tachypnea in newborn.
• Laboratory test shows anion gap metabolic acidosis, hypoglycemiae, ketosis, and hperammonemia.
• These metabolic deragnements manifest as hypotonia, lethargy, vomiting, and respiratry distress (tachypnea due to acidosis) int he neonatal period.
• Diagnosis is confirmed by the presence of elevated urine methylmalonic acid and propionic acid.

Question 688

Ischemic stroke:

• 12- 24 hours: “red neurons” (eosinophilic cytoplasm, pyknotic nuclei, loss of Nissl substance)
• 24-74 hours: Neutrophilc infilitration
• 3-7 days: Macrophage/microglia infiltration & phagocytosis
  
  • Macrophages filled with lipids (degradation of myelin).
• 1-2 weeks: Reactive gliosis & vascular proliferation around the necrotic area
  
  • Gliosis: proliferation of astrocytes following injury.
  • Liquefactive necrosis.
• > 2 weeks: Glial scar formation.

Answer 688

Hippocampus: most vulnerable.

Question 689

Piriformis:

• Acts to externally rotate the thigh when extended and abduct the thigh when flxed.
• Passes through the greater sciatic foramen; muscle injury or hypertrophy can compress the sciatic nerve to cause sciatic-like symptom known as piriformis syndrome
  
  • Tender with deep palpation or on stretching with adduction and internal rotation.

Question 690

Sarcomere

• A band: composed of thick filaments only ;always remains the same length.
  *

Question 691

Anterior 2/3 of tongue (in front of terminal sulcus)

• Chorda tympani (taste)
• Trigeminal nerve V3

Posterior 1/3 of tongue (posterior to terminal sulcus)

• CN IX

Question 692

Pyruvate kinase deficiency:

• Congenital hemolytic anemiae due to impaired glycolytic ATP generation.
• As RES in the splenic red pupl are involved in removal of damaged RBCs, their increased activity int he setting of PKD causes them to undergo hyperplasia, resulting in splenomegaly.

Question 693

Damage to the brainstem at/below the level of the red nucleus (e.g., midbrain tegmentum, pons) typically results in decerebrate (extensor) posturing.

Answer 693

In contrast, damage to neural structures above the red nucleus (cerebral hemisphere, internal capsule) typically results in decorticate (flexor) posturing.

Question 694

Lower extremity anatomy

Answer 694

1. Gluteus medius, gluteus minimus, tensor fascia lata

• Abduction of the thigh.
• Supplied by superior gluteal nerve exits the pelvis through the greater sciatic foramen above the piriformis.
  
  • Can be injured from injection at superomedial quadrant of the left buttock.

2. Gluteus maximus:

• Extension of the thigh.
• Supplied by inferior gluteal nerve that exits the pelvis through the greater sciatic foramen below the piriformis.

3. Piriformis:
   * External rotator of thigh.

Question 695

Sex

Age

Depression

Previous attempt

Ethanol or drug abuse

Rational thinking loss

Sickness

Organized plan

No spouse or other social support

Stated future intent

Answer 695

1. A history of previous suicide attempt is the strongest single risk factor for suicide.
2. Most common method in the US is firearms; access to guns increase risks of suicide completion.

Question 696

Bisphosphonate:

• Alendronate, risedronate
• Strucutre similar to pyrophosphate.
• Inhibition of mature osteoclast-mediated bone resorption.
• Can cause osteonecrosis (avascular osteoporosis) of jaw.

Question 697

Ataxia telangiectasia:

• Cerebellar ataxia
• Telangiectasias: superficial blanching nests of distended capillaries.
• increased risk of sinopulmonary infections.
• Mutation of ATM gene, responsbile for DNA break repair.

Question 698

MMSE:

• Assessing for attention & concentration: counting down from 100 by intervals of 3 or 7, reciting the months of the year in reverse order, or spelling “world” backwards.

Question 699

The upper midbrain contains neural structures (e.g., optic nerve, pretectal nuclei, Edinger-Westphal nuclei, occulomotor nerve) that mediate the direct and consensual pupillary light reflex.

Answer 699

• Optic Nerve - Afferent Limb
• Occulomotr Nerve - Efferent Limb
  
  • Deficiency: Ptosis, mydraisis, “down-and-out”

Question 700

Rapid correction of chronic hyponatremia may lead to osmotic demyelination of the axons in the central part of teh pons: central pontine myelionlysis.

Question 701

Delirium: a reversible, acute confusional state involving a reduced or fluctuating level of consciousness with difficulties sustaining attention & significantly impaired memory and executive function.

Question 702

Type I:

• Aerobic metabolism
• High myoglobin (oxygen storage) & Mitochondrial (aerobic respiration) concentration.
• Postural maintenance: paraspinal muscles.

Answer 702

Type II:

• Rapid forceful pulses of movement
• Drive ATP energy through anaerboic glycogenolysis and subsequetn glycolysis.

Question 703

Etanercept: decoy receptor for TNF-alpha

Infliximab, adalimumab, Certolizumab: anti-TNF monoclonal antibodies.

Answer 703

Need to be evalulated for latent tuberculosis.

Question 704

ADHD:

Answer 704

1. Psychostimulants: methylphenidate & amphetamines

• MOA: inhibit uptake of NE & Dopamine.
• ADR: Decreased appetite, weight loss, and insomnia.

Question 705

Superior orbital fissure: CN III, IV, V₁, VI

Foramen rotundum: V₂

Foramen ovale: V₃

Question 706

Thalamic stroke: unilateral pure hemisensory loss.

• VPL: receives input from the spinothalamic tract & DCML
• VPML: receives input from the trigeminal pathway
• Damage to these nuclei may result in complete contralateral sensory loss (e.g. touch, pani/temperature, vibration/proprioception).

Question 707

• Anterior knee pain, usually due to repetitive or prolonged kneeling.
  
  • Carpet layers, mechanics, and plumbers.

Answer 707

• Prepatellar bursitis, sometimes called “housemaid’s knee”.
• Bursa: a fluid-filled synovial sac that serves to alleviate pressure from bony prominences and reduce friction between muscles and tendons.

Question 708

Alzheimer’s disease:

• Mild-to-moderate progressive memory loss.
• Neurofibrillary tangles: Intracellular inclusions formed primarily of the cytoplasmic microtubules binding protein, tau.
• Seniles plaques: abnormal fragment of amyloid precursor protein.
  
  • Apple-green birefrigence under Congo red polarized light.
  • Amyloid angiopathy
• Decreased Ach levels in the hippocampus and nucleus basalis of Meynert.

Answer 708

Risk factors ?

• APP on chromosome 21 (thus related to down syndrome)
• Presenilin 1 & 2
• ApoE4 (ApoE2 ↓ risk).

Question 709

Fractures to the orbital floor commonly result from direct frontal trauma to the orbit:

• The infraorbital nerve runs along the orbtial floor in a groove in the maxilla before exiting the skull just inferior to the orbit.
• Damage can result in parethesia of the upper cheek, upper lip, and upper gingiva.

Answer 709

Orbital blowout fractures: most commonly involve the ethmoid and maxillary sinuses.s

Question 710

Osgood-Schlatter disease:

Answer 710

• Overuse injury caused by repetitive strain and chronic avulsion of the secondary ossification center of proximal tibial tubercle.
• A very common cause of knee pain in young adolescent athletes after a recent growth spurt.
• Pain and swelling at the tibial tubercl,e the insertion point of the paterllar ligament.

Question 711

The amassed myofibroblasts initiate wound contraction during healing by second intention. Contractures may occur when unusually pronounced MMP activity results in excessive wound contraction.

Answer 711

Keloids: hypertrophic scars in which excessive collagenous scar tissue deposited by fibroblasts permanently extends beyond the margins of the original wounds.

Question 712

Dobutamine:

• B₁ (increased production of cAMP and increased cytosolic Ca²⁺ concentration) > B₂
• Used for management of refractory heart failure associated with severe left ventricular systolic dysfunction and cardiogenic shock.
• Causes positive inotropy/chronotropy; mild vasodilation: can increase myocardial oxygen consumption, which can trigger or exacerbate M.I.

Question 713

Cleft lip:

• Fusion of the 2 medial nasal prominences forms the midline intermaxillary segment.
• Intermaxillary segment fuses with the left & right maxillary prominences.

Answer 713

Cleft palate:

• The palatine shelves fail to fuse witih one another or with the primary palates.

Question 714

The left ventricle forms the apex of the heart and can reach as far as the 5th intercostal space at the left MCL. The lungs overlap much of the anterior surface of the heart (laterally directed anterior chest wall stab wound at the fifth intercostal space along the left MCL).

Question 715

Aortic Stenosis

Answer 715

• Systolic crescendo-decrescendo murmur best heard at the base of the heart with radiation to the neck. Soft second heart sound due to reduced mobility of the aortic leaflets.
• The most common cause in elderly patients in developed countires is degenerative calcification of the aortic valve leaflets (of either bicuspid or tricuspid valves).
• The most common cause in developing nations is rheumatic valve disease (fusion of valve commissures due to repetitive inflammation).
• The maximum pressure difference between the left ventricular and aortic pressure tracings corresponds to the peak intensity of a cardiac murmur during auscultation.
• Pulsus parvus (diminshed stroke volume) et tardus (prolonged LV ejection time).

Question 716

Calcium efflux from cardiac cells prior to relaxation is primarily mediated via an Na+/Ca2+ exchange pump and SERCA (sarcoplasmic reticulum Ca2+-ATPase pump).

Question 717

Lateral epicondylitis (tennis elbow):

• Primary attachment point for the extensor carpi radialis brevis (ECRB) and extensor digitorum, which are involved in wrist extension.
  
  • Radial nerve: Affected by anterolateral displacement of humerus.

Answer 717

Medial epicondylitis:

• Wrist flexors at their attachment on the medial epicondyle.
  
  • Median & Ulnar nerve.

Question 718

Occlusion of AICA: lateral pontine syndrome

• Ipsilateral loss of pain/temperature in the face *** (due to infarction of the trigeminal nucleus)
• Contralateral loss of pain/temperature in the trunk and extremities (due to infarction of the lateral spinothlamic tract).
• Ipsilateral facial weakness (facial nucleus)
• Ipsilateral hearing loss (cochlear nuclues)

Question 719

Primary central nervous system lymphoma (PCNSL)

• Large, solitary lesions.
• Diffuse, large cell non-Hodgkin lymphoma of B-cell origin.
  
  • EBV is identified in almost all cases.

Question 720

Blastomyces dermatitidis:

• Ohio & Mississippi river valleys, great lakes region.
• Pulmonary: pneumoniae.
• Culture (25C): branching hypae
• Biopsy: large, round yeasts with double refractile wall and single broad-based bud.

Answer 720

Question ID: 103.

Question 721

Phosphodiesterase inhibitor that inhibits platelet aggregation and acts as a direct arterial vasodilator.

Question 722

Ulcerative STDs:

1. Chancroid;

• H.ducreyi
• Multiple & deep ulcers
• Base may have gray to yellow exudate
• Inguinal lymphadenopathy.

2. Chancre:
   * Painless genital ulcer caused by a primary syphilis.

Question 723

Competitive inhibitors compete with substrate for active binding sites on enzymes.

• Additional substrate is required to achieve the same rate of reaction, increasing the measured value of the Km.
• They do not affect enzyme function; therefore , maximal velocity (Vmax) is unchanged in their presence.

Question 724

2-8 weeks after exposure to high-risk drugs (eg, anticonvulsants/allopurinol/sulfonamides/antibiotics), a patient presents with fever, generalized lymphadenopathy, facial edema, and diffuse skin rash.

Answer 724

DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS) SYNDROME.

Question 725

Substance-induced psychotic disorder is diagnosed when stimulant intoxication presents with:

• Pprominent psychotic symptoms: delusions, hallucinations
• Physical findings : tachycardia, HTN, hyperthermia, diaphoresis, mydriasis.

Question 726

HbS:

• Negatively charged amino acid (glutamate) –> Nonpolar amino acid (valine)
• Promots hydrophobic interaction among Hb molecules and results in HbS polymerization and erythrocyte sickling.

HbC:

• Glutamate residue replaced by lysine in the beta globin gene.
• Moves even slower toward the anode on gel electrophoresis.
• Typically asymptomatic (mild fatigability) + mild hemolytic anemia + splenomegaly.

Both are missense mutations.

Question 727

Transformation: allows the bacteria to take up exogenous DNA fragments, integrate the DNA into its genome, and express the encoded proteins.

Answer 727

Through this method, nonvirulent strains of S. pneumoniae that do not form a capsule can acquire the genes that code for the capsule and therefore gain virulence.

• A feature of many bacteria, especially S. pneumoniae**, H. inlfuenzae type b, Neisseria (ShiN).

Question 728

ADH also increases the number of passive urea transporters in the inner medullary collecting duct, allowing a substantial fraction of the highly concentrated urea to diffuse down its concentration gradient into the medullary interstitium.

Question 729

• A selective PDE-3 enzyme inhibitor.
• Cardiac myocytes: Increased cAMP levels promote calcium influx, which in turn increases myocardial contractility (positive inotropy).
• Vascular tissue: Systemic arterial and venous dilation.

Question 730

Abcavir is contraindicated if patient has HLA-B*5701 mutation due to increased risk of hypersensitivity.

Question 731

Binds to the immunophilin FK-506 binding protein (FKBP) in the cytoplasm, forming a complex that binds and inhibits mTOR.

Inhibition of mTOR signaling blocks IL-2 signal transduction and prevents cell cycle progression and lymphocyte proliferation.

Answer 731

• Everolimus and its pharmacologic counterparts are cytostatic drugs taht inhibit mTOR, blocking the cell cycle between the G1 and S phase to reduce smooth muscle cell proliferation.

Question 732

The proximal ureter receives its blood supply from the renal artery whereas the distal ureter is supplied by the superior vesical artery.

Question 733

The left kidney lies immediately deep to the tip of the ?

Answer 733

12th rib.

Question 734

Tx for specific phobia?

Answer 734

CBT.

Question 735

Heart muscle is perfused during diastole; increased heart rate shortens the time of ventricular relaxation (duration of diastole); therefore, the time available for maximal coronary blood flow decreases and consequently becomes the major limiting factor for coronary blood supply to the myocardium.

Answer 735

Myocardial oxgyen extraciton is very high; as a result, cardiac venous blood is the most deoxygenated.

Question 736

Thoracentesis should be performed above the 8th rib in the midclavicular line, the 10th rib along the midaxillary line, and the 12th rib along paraveterbral line.

Answer 736

Insertion of a needle lower than these points increases the risk of penetrating abdominal structures, and insertion of the needle on the inferior margin of the rib risks striking the subcostal neurovascular bundle (especially intercostal N).

Question 737

Prostacyclin (PGI₂)

• Vasodilates.
• Inhibits platelet aggregation.
• Increasea vascular permeability.
• Opposes TXA_2.

Question 738

• Widespread musculoskeletal pain & soft tissue tenderness.
• Fatigue.
• Impaired attention & concentration.
• Psychiatric disturbances (eg, depression, anxiety)
• Symptoms lasting for >3 months
• Normal acute phase reactants (eg, ESR, CRP) & other inflammatory markers.

Question 739

Advance care planning for end-of-life issues should ideally be initiated during outpatient visits with the primary care provider.

Answer 739

Patient’s wishes on an advance directive overrule any family member’s objection.

In case it’s missing, need to follow next kin’s opinions (usually spouse or children.

Question 740

• Major depressive or manic episodes concurrent with symptoms of schizophreniae.
• Lifetime history of delusions, or hallucinations for >2 weeks in the absence of major depressive or manic episode.
• Mood symptoms are present for majority of illness
• Not due to substances or another medical conditions.

Question 741

The internal laryngeal nerve mediates the afferent limb of the cough reflex above the vocal cords. Foreign bodies (eg. chicken or fish bones) can become lodged in the piriform recess and may cause damage to the nerve, impairing the cough reflex.

Question 742

The urachus is a remnant of the allantois that connects the bladder with the yolk sac during fetal development.

Complete failure of obliteration of the urachus results in a patent urachus that connects the umbilicus and bladder. Patients present with straw-colored urine discharge from the umbilicus, which is exacerbated by crying, straining, or prone position.

Answer 742

MediaN umbilical ligament.

Question 743

If a drug has a large molecular weight, is bound extensively to plasma proteins, or is highly charged (hydrophilic), then the drug generally remains the plasma compartment and the volume of distribution is usually low as in the case above (3~5 liters).

Answer 743

Drugs that are avidly bound in the tissues exhibit the highest volumes of distribution, often much higher than the total body water volume, because these drugs accumulate readily within cells thereby maintaining low plasma concentrations.

V_d= amount of drug given (mg)/ initial plasma concentration of drug (mg/L)

Question 744

Vertebral osteomyelitis should be suspected in patients with new or worsening back pain, fever, and recent endocarditis or bacteremia (esp. S.aurues). It should also be suspected if there are new neurologic findings and fever with or without back pain.

• MRI is preferred.

Answer 744

• Hematogenous osteomyelitis occurs predominantly in children and most frequently affects the long bones.
  
  • S. Aureus
  • S. pyogenes (GAS)

Question 745

Adenosine and dipyridamole(PDE inhibitor; similar to cilostazol) are selective vasodilators of cornary vessles that can cause coronary steal, a phenomenon in which blood flow in ischemic areas is reduced due to ateriolar vasodilation in nonischemic areas.

Question 746

Polymyositis:

• Anti-Jo-1(Histidyl-tRNA synthetase)
• Symmetrical proximal muscle weakness; increasing difficutly climbing stairs, getting up from a chair, carrying heavy ojbects.
• Endomysial mononuclear inflammatory infiltrate with CD8+ T cells.

Answer 746

Dermatomyositis:

• Involves malar rash (similar to that in SLE but invovles nasolabial folds)
• Gottron papules
• Heliotrope rash.
• ↑ risk of occult malignancy.
• Perimysial inflammation and atrophy with CD4+ T cells.

Question 747

1. Exposure to contaminated water:

• Recent travel (cruise/air-conditioned hotel visit)
• Hospital/nursing home stay.

2. Clinical findings:

• Fever > 39
• Bradycardia relative to high fever
• Headache & confusion
• Watery diarrhea

3. Laboratory findings:

• Hyponatremia
• Sputum gram stain shows many neutrophils but few or no organisms: faintly staining gram-negative bacillus that’s facultatively intracellular.
• Grows on buffered charcoal yeast extract (BCYE).

Question 748

• Paroxysmal breathlessness and wheezing in a young paitnet unrleated to ingestion of aspirin, pulmonary infection, inhaled irrtants, stress, and/or and exercise.
• Bronchoprovocation: methacholine
• Tx: ipratropium bromide & scopolamine.

Answer 748

• Eosinophils are recruited and activated by IL-5 secreted by T_H2 type helper T-cells.
  
  • Secrete MBP, a potent anti-helminthic toxin capable of causing damage to epithelial and endothelial cells.
• Charcot-Leyden crystals: the crystalloid bodies.

Question 749

Physicians aren’t required to provide medical services that are against their personal beliefs; however, once a patient-physician relationship is established, the physician is obligated to refer the patient to another provider who can perform the requested medical service.

Question 750

• Proximal tubular cell ballooning and vacuolar degeneration in a patient with acute renal failure
• Granular (“muddy brown”) casts.

Answer 750

1. Toxin:
   * Presence of oxalacte crystals: ethylene glycol poisoning.
2. Ischemic:
   * Prolonged hypotension or severe infection.
3. Steps:

• Initiation stage: injury to renal tubules precipated by hemorrhage, acute MI, sepsis, surgery, etc.
• Maintenance stgage: decreased urine output, fluid overlpad, increasing BUN/Cr, hyperkalemiae
• Recovery: Gradual increase in urine output leading to high-volume diuresis; electrolyte abnrmalities may include decreased concentration of K, Mg, PO4, and Ca.

Question 751

Hep. E

Answer 751

• Non-enveloped, ssRNA virus that spread through the fecal-oral route.
• The most concerning feature of Hep. E infection is their high mortality rate observed in infected pregnant women.

Question 752

Paradoxcial Embolism:

Answer 752

PFO

• After delivery, umbilical cord clamping and decreased pulmonary vascular resistance lower right atrial pressure and raise left atrial pressure; that pushes the septum primum against the septum secundum.

ASD

• Wide-fixed splitting of S₂ that does not change with respiration.

Question 753

Genomic imprinting: caused by DNA methylation, an epigenetic process in which genes can be silenced by attaching methyl groups to cytosine residues in the DNA molecule.

Question 754

Question 755

X-linked agammaglobulinemiae:

• Mutation in the Bruton tyrosine kinase: failure of bone marrow pre-B cells (CD19+, CD20+) to develop into mature circulating B lymphcytes.
• Pan-hypogammaglobulinemiae; pryogniec (encapusualted) bacteriae.s

Answer 755

Germinal centers and primary lymphoid follicles do not fomr due to an absence of B cells.

Question 756

Locus coeruleus is a paired brainstem nucleus located in the posterior rostral pons near the lateral floor of the fourth ventricle and functions as the principal site for NE synthesis in the brain.

• Involved in the control of mood, arousal (RAS), sleep-wake states, cognition, and autonomic function (eg, blood pressure control).
  *

Answer 756

Serotonin: Raphe nucleus.

Question 757

Inhibition of neprilysin leads to increased levels of endogenous natiuretic peptides, which promote benefical effects in heart failures.

Answer 757

ANP, secreted by atrial cardiomyocytes lowers B.P. through peripheral vasodilation, natriuresis, and diuresis.

• Work through increasing cGMP —> NO

Question 758

Interscalene nerve block can also cause?

Answer 758

Transient ipsilateral diaphragmatic paralysis in nearly all patients by anesthetizing the roots of the phrenic nerve (C3-C5) as they pass through the interscalene sheath.

Question 759

Monophosphorylation of acyclovir by a viral TK is the first (and rate-limitin) step in conversion of acyclovir to its active triphosphate form.

Answer 759

Acyclovir and related drugs (famciclovir, valaciclovir), are more effective against HSV and VZV than CMV and EBV.

If a patient is missing viral kinase, then cidofovir is the next best choice.

Question 760

Naltrexone: blocks the mu-opioid receptor and can be initiated while the individual is still drinking; blocks the rewarding and reinforcing effects of alcohol and has been shown to reduce craving.

Answer 760

Acamprosate: modulates glutamate neurotransmission at the NMDA receptor and is recommended once abstinence has been achieved.

Question 761

Providing high-concentration supplemental oxygen allows lung regions with relatively poor ventilation to have higher oxygen levels, reversing pulmonary vasoconstriction.

Answer 761

The redistribution of blood flow away form well-vnetilated alveoli leads to an increase in physiologic dead space with a correpsondign reduction in totla alveolar ventilation.

Question 762

Changing the cutoff point to a lower value would cause more patients with the disease to test positive (TP, FN), increasing sensitivity of the test.

Question 763

Lichtenberg figures (erythematous cutaneous marks in a fern-leaf pattern) is presented on a patient. Which is most likely the primary cause of his death?

Answer 763

Cardiac arrhythmia & pulmonary distress.

Question 764

Ascending loop of Henle:Rrelatively impermeable to water, so the tubular fluid remains hypotonic.

Reabsorption of solutes continues to occur; thus, fluid in the DCT is the most dilute (lower osmolarity, approaching 100 mOsm/L).

Question 765

Normal

• Rinne: AC > BC bilaterally.
• Weber: midline.

Conductive hearing loss

• Rinne: BC > AC in affected ear.
• Weber: lateralizes to affected ear.

Sensorineural hearing loss

• Rinne: AC > BC bilaterally (normal).
• Weber: lateralizes to unaffected ear.

Question 766

• Gram (+), spore-forming rod that produces anthrax toin. The only bacterium with a polypeptide capsule (contains D-glutamate).
• Increases cAMP concentration ~ similar to B. pertussis.

Answer 766

• Cutaneous anthrax
  
  • An ulcer with central black eschar surrounded by edema.
• Pulmonary hemorrhage.
  
  • Wool-sorters.

Question 767

Class 1c antiarrhythmics such as flecainide are potent sodium channel blockers that have increased effect at faster heart rates (use-dependence).

This makes them more effective at treating tachyarrhythmias, but also can cause prolonged QRS duration at higher rates.

Answer 767

Causes QRS prolongation with little effect on QT interval duration (affects phase 0 depolarization).

Question 768

Accessory nipples are the most common congenital breast anomaly resulting from failed regression of the mammary ridge in utero. They are usually asymptomatic but can become tender along with breast tissue during times of hormonal fluctuation.

Question 769

High serum Mg²⁺ concentrations?

Answer 769

• ↓ DTRs
• Lethargy
• Bradycardia
• Hypotension
• Cardiac arrest
• Hypocalcemiae

Question 770

Angiogenesis is predominantly drivey by ?

Answer 770

VEGF

FGF

Question 771

DNA polymerase I:

• The removal of RNA primers and their replacement with DNA
• 5’ to 3’ exonuclease activity

Answer 771

DNA polymerase III

• 5’ to 3’ polymerase
• 3’ to 5’ exonuclease (proofreading) activity.

Question 772

Capitation:

• An arrangement in which a payor (individual, employer, or government entity) pays a fixed, predetermined fee to cover all the medical services required by a patient.

Question 773

Neonatal intraventricular hemorrhage usually occurs in the fragile germinal matrix and increases in frequency with decreasing age and birth weight.

It’s a common complication of prematurity that can lead to long-term neurodevelopmental impairment.

Question 774

Colchicine:

Answer 774

1. May be used for patients with RA who can’t use NSAIDs due to PMH of PUD.
2. Disrupts microtubule polymerization - cytoskeleton.
3. ADR: N/V, diarrhea.

Question 775

E. coli:

• Motile, gram-negative, facultative anaerobic rod.
• Green metallic sheen on EMB agar.
• Grows on MacConkey agar.

Answer 775

1. Lipid A of LPS:

• Widespread release of IL-1, IL-6, TNF-alpha
• Bacteremia & Septic shock.

2. K1 capsular polysaccharide:

• Prevent phagocytosis & complement-mediated lysis.
• Neonatal meningitis

3. Verotoxin (Shiga-like toxin)

• Inactivates the 60s ribosomal component.
• Gastroenteritis (bloody).

4. Enterotoxin (ETEC)

• LT: similar to cholera toxin, increases cAMP
• ST: cGMP.
• Self-resolving gastroenteritis (watery).

5. P fimbriae

• Allows adhesion to uroepithelium.
• UTI.

Question 776

Under the Health Insurance Portability and Accountability Act, physicians may disclose patient information to friends & family members only when the patient gives explicit permission or does not object when given a reasonable opportunity.

• Can still share basic information when patient is unconscious.

Question 777

Prominent, round, basophilic bodies contained within large nuclei.

Answer 777

Nucleolus:

• All rRNA except 5s RNA is transcribed in the nucleolus.
• RNA polymerase I: 18s, 5.8s, 28s ribosomal rRNA

RNA Polymerase II: synthesizes both mRNA and snRNA.

RNA polymerase III: tRNA.

Question 778

The optimal location for needle insertion during a lumbar puncture is the L3/L4 or L4/L5 space as this is well below the spinal cord termination site (conus medullaris).

The L4 vertebral body lies on a line drawn between the highest points of the iliac crests.

Question 779

The coronary sinus communicates freely with the right atrium and will become dilated secondary to any factor that causes increased right atrial pressure. The most common cause is pulmonary HTN, leading to elevated right heart pressures.

Question 780

Nitric oxide is synthesized from arginine by NO synthase.

Answer 780

1. Venodilation
2. ADRs: headache, cutaneous flushing, lgihtheadedness, hypotension, and reflex tachycardia.
3. Most important factor(s) involved in coronary blood flow autoregulation.

Question 781

Recurrent abdominal pain and pancreatic calcifications: chronic pancreatitis, the most common cause of which is ethanol abuse. Hepatomegaly is likely due to alcohol-associated hepatic steatosis.

Answer 781

Alcoholics often develops macrocytic anemiae due to folic deficiency & vitamin B12 deficiency.

Question 782

Excessive and chronic worry, feeling on edge, muscle tension, and insomnia are characteristic of GAD.

Answer 782

SSRI & SNRIs are 1st line treatment.

Question 783

During the skeletal muscle contraction cycle, ATP binding to myosin causes release of the mysoin head from its binding site on the actin filament.

Question 784

Verapamil is a nondihydropyridine CCB that acts by blocking L-type calcium channels, preventing the intial calcium influx into cardiac myocytes and vascular smooth muscle cells. Becasue skeletal muscle isn’t dependent on extracellular calcium influx, CCB do not affect skeletal muscle contractility.

Answer 784

A patient’s presentation (constipation, new-onset second degree AV block, and syncope) in the setting of new medication use for AF is likely due to CCB: Diltiazem & verapamil.

vs.

Amlodipine:

• Dihydropyridine CCB
• ADRs: headache, dizziness, flushing, and peripheral edema.

Question 785

Aortic regurgitation:

• best heard along the left sternal border at the third and fourth intercostal spaces.
• Aortic root dilation, bicuspid aortic valve, endocarditis.

Answer 785

• Failure of the aortic valve leaflets to remain closed during diastole results in a portion of left ventricular stroke volume to leak from the aorta back into the left ventricle.
• The regurgitant blood flow increases left ventricular EDV (preload) and wall stress, with resultant eccentric hypertrophy.
• The gradual increase in left ventricular chamber size due to eccentric hypertrophy increases stroke volume = can lead to wide pulse pressure & head pounding.

Question 786

Retinal artery occlusion: acute, painless, monocular vision loss

• Internal carotid artery –> ophthalmic artery –> retinal artery.

Question 787

ADRs of Omeprazole (PPI):

Answer 787

↓ Mg²⁺ and Ca²⁺ absorption, leading to increased risk of osteoporosis & hip fractures.

Question 788

Central chemoreceptors: Increased PaCO₂ is the major stimulator.

Answer 788

Peripheral chemoreceptors: found in the cartoid and aortic bodies; primary sites for sensing arterial PaO₂ and are stimulated by hypoxemiae.

Question 789

Damage to the left temporal hemiretina will disrupt the transmission of visual information along the ipsilateral optic nerve, lateral optic chiasm, optic tract, LGN, optic radiations, primary visual cortex.

Question 790

Cerebral amyloid angiopathy is the most common cause of spontaneous lobar hemorrhage, particularly in the elderly.

Answer 790

Most common sites of hemorrhage include occipital (homonymous hemianopsia) and parietal lobes (contralateral hemisensory loss).

Question 791

Heart embryology

Answer 791

Left horn of sinus venosus: Coronary sinus.

Right horn of sinus venosus: Smooth part of right atrium (sinus venarum).

Right common cardinal vein and right anterior cardinal vein: SVC.

Question 792

Resistance of blood vessels:

(8n X length) / πr⁴

Answer 792

Total resistance of vessels in series:

• R_T = R₁ + R₂ + R₃

Total resistance of vessels in parallel:

• 1/R_T = 1/R₁ + 1/R₂ + 1/R₃

Question 793

Jugular venous tracing

Answer 793

a wave: Atrial contraction.

• Absent in AF

c wave: Bulging of tricuspid valve during right ventricular contraction.

x descent: right atrial relaxation.

v wave: right atrial presure due to filling against closed tricupsid valve.

y descednt: RA emptying into RV.

Question 794

Cardiology misc.

Answer 794

1. Speed of conduction: Purkinje > atria> ventricles> AV node.
2. PCWP: left atrial pressure (N: 4-12).
3. Lungs: Hypoxia causes vasoconstiction so that only well-ventilated areas are perfused.
4. CO = SV X HR= O₂ consumption / (AV O² content difference).

Question 795

Radial head subluxation (nursemaid’s elbow) results form sudden traction on the outstretched and pronated arm of a child.

Answer 795

Annular ligament;

injured arm held in flexed and pronated position.

Question 796

Cytokines:

Answer 796

1. T_H-1
   *
2. T_H-2

• IL-4: IgE
• IL-5: IgA & recruits eosinophils (asthma exacerbation).

3. IL-2 (aldesleukin) : Enhances activity of NK cells & macrophages & growth factor for T lymphocytes.

Question 797

Achondroplasia:

Answer 797

1. Limb shortening with normal torso length & specific craniofacial features
2. FGFR3 mutation affecting endochondral ossification (long bones vs. intramembranous ossification); exaggerated inhibiton of chondrocyte proliferation.
3. Autosomal dominant mutation; the risk for the child to be short is about 50%.

Question 798

Inflammatory acne:

Answer 798

The pathogenesis of acne centers on the sebaceous glands and hair follicles.

• Colonization of the glands with Propionibacterium acnes.
• Holocrine: produce their lipid-rich secretory product by lysis of the cell membrane and release of cytoplasmic contents.

Question 799

• Uric acids: Diamond- or rhomboid-shaped crystals.
• Risk factors: Low urinary pH (eg, acidic) with high uric acid concentration.
• May occur in the setting of gout, high cell turover states (eg, lymphoproliferative disorders), metabolic syndrome, chronic diarrhea (losing HCO^3-, leading to increased H+ ion excretion in the kidney).

Answer 799

The lowest pH along the neprhon is found in the distal tubules and collecting ducts; so these are the segments of the nephron that become obstructed by uric acid crystals.

Question 800

Polyprotein product of the env is glycosylated to become gp160; then proteolytically cleaved within the ER and Golgi to form gp120 and gp 41.

gp 120 mediates viral attachment by binding to the CD4 receptor of susceptible cells. Transmembrane gp41 anchors gp120 through noncovalent interactions, thereby mediating the fusion process between viruses and target cells.

• Fusion inhibitor: Enfuvirtide

Answer 800

The HIV virus uses the CD4 protein as a primary receptor, and the chemokine receptor CCR5 serves as a coreceptors.

• CCR5 antagonist: Maraviroic: Inhibits HIV entry by allosteric blocking of HIV gp120 interaction with CCR5 (tropsim testing required).

Question 801

Theophylline

Answer 801

Methylxanthines: an adenosine receptor antagonist and PDE inhibitor that’s sometimes used as an alternate therapy for asthma and COPD.

Predominantly metabolized by the hepatic cytochrome oxidase.

ADR:

• Central nervous system stimulation (eg, tremor, insomnia, seizures)
• GI disturbances
• CV abnormalities (eg, hypotension, tachycardia, cardiac arrhythmias)
  *

Question 802

Baclofen, an agonist at the GABA-B receptor, is effective as monotherapy for the Tx of spasticity secondary to both brain and spinal cord disease, including MS.

Question 803

• provides sensation to the suprapubic and gluteal regions and motor function to the anterolateral abdominal wall muscles.

Question 804

Shigellae

• Non-lactose fermenting organisms that produce acid (not gas) during glucose fermentation
• Non-motile & do not produce H₂S.
• Invades GI mucosa, particularly via the M cells that overlie the Peyer’s patches.
• Can spread via host-cell actin polymerization.

Answer 804

Y. enterocolitica can cause inflammation and enlargement of the lymphoid tissue around the appendix and terminal ileum (pseudoappendicits), leading to right lower quadrant pain that can be confused with acute appendicitis.

Question 805

• Use bed only for sleep & sexual activity (no reading, television, eating)
• Go to bed only when sleepy
• Leave bed when unable to sleep & go to another room
• Maintain a fixed wake-up time, including on weekends.

Answer 805

*

Question 806

Histoplasma

• Caves (exposure to bats) or cleaning bird cages or coops.
• Ovoid cells within macrophages
• Endemic to the Mississippi and Ohio River basins.
• The radiographic changes of chronic lung disease resembles those of pulmonary tubuerculosis
  
  • Cavitary lesions form in the upper lung lobes, and calcified nodes and fibrotic scarring may also be present.

Answer 806

• Blastomyces*
• Round yeasts, with single broad-based buds and thick, doubly refractive walls.
• Coccidioides*
• Thick-walled spherules with endospores; bigger than RBCs
• Endemic to the Southwestern United Sates (eg, southern and central California, Arizona, New Mexico, and western Texas), Northern Mexico, and some regions of Central and South America.

Question 807

P. aeruginosa

• Nonlactose-fermenting, oxidase-positive, motile, Gram-negative rod.\
• Common in neutropenic patients ***
• Most common cause of malignant otitis externa (MOE), a serious infection fo the ear seen in elderly diabetic patients.
• Ecthyma gangrenosum: Skin patches exhibiting necrosis and ulceration as a result of insufficient blood flow.
• Tx: Cephalosporins: ceftazidime(3rd gen) & cefepime (4th gen)

Question 808

• Release & subsequent depletion of substance P.

Question 809

CD14: a surface marker of the monocyte-macrophage cell lineage.

Question 810

Angiotensin I is converted to angiotensin II primarily within the small pulmonary vessels by endothelial-bound ACE. Therefore, levels of angiotensin II are higher in the pulmonary vein when compared to pulmonary artery.

Question 811

• Janeway lesions: Macular, erythematous, nontender lesions on the palms & soles.
• Osler nodes: Painful, violaceous noduels seen on the fingertips & toes
• Roth spots.
• Systemic emboli (cerebral, pulmonary, splenic infarcts).

Answer 811

• Microscopic deposits of platelets and fibrin occur spontaneously in individuals with valvular disease secondary to endocardial injury from turbulent blood flow.
  
  • Rheumatic heart disease, MVP, prosthetic valves, congenital heart disease.
• Colonized by microorganisms (eg, S. viridans).
• Can result in mitral regurgitation.

Question 812

Alcohols

• Disruption of cell membranes
• Denaturation of proteins

Chlorhexidine

• Disruption of cell membrane
• Coagulation of cytoplasm

Hydrogen peroxide

• Produces destructive free radicals that oxidize cellular components

Iodine

• Halogenation of proteins & nucleic acids.

Answer 812

Ether and other organic solvents dissolve the lipid bilayer that makes up the outer viral envelopes.

Question 813

Salmonella typhi:

• H₂S production
• Flagella present
• Acid-labile; large inoculum required (vs. Shigellae)
• Causes typhoid fever
  • Waterry diarrhea or constipation.
  • Abdominal pain
  • Salmon-colored rose spots on the chest/abdomen.
• Chronic carrier: gallbladder.

Answer 813

Salmonella spp.

• Poultry, eggs, pets, and turtles.
• Gastroenteritis.

Question 814

Dx?

Answer 814

Idiopathic pulmonary fibrosis:

Slowly progressive exertional dyspnea and dry cough, a restrictive profile on pulmonary function testing (PFT), and interstitial fibrosis with cystic air space enlargement.

• Honeycombed on abdominal CT lined by hyperplastic type II pneumocytes.
• Reticular findings on CXR.

Question 815

Left-sided heart disease can cause pulmonary HTN by increasing pulmonary venous pressure and congestion. This leads to a passive increase in pulmonary arterial pressure, which is made worse by reactive vasoconstriction and structural remodeling of the pulmonary vasculature secondary to impaired NO availability and increased endothelin expression.

Question 816

Transposition of great vessels

Answer 816

Due to linear (rather than spiral) development of the aorticopulmonary septum in uterus, resulting in an anteriorly positioned aorta connected to the right ventricle and an posteriorly positioned pulmonary artery connected to the left ventricle.

• Not compatible with life unless VSD, ASD, or PDA exists to allow mixing of the blood: PGE may be indicated.

Question 817

Activating mutation:

• KRAS.
• Oncogenes.

Answer 817

Loss-of-function mutation:

• Tumor-suppressor gene.
• APC, BRCA1, RB, TP53

Question 818

Asthma treatment:

Answer 818

Omalizumab (anti-IgE antibodies):

• Effective & accetpable add-on therapy for patients with severe allergic asthma.

Zileuton:

• A specific inhibitor of the enzyme 5-lipoxygenase and inhibits LT formation (LTB4, LTC4, LTD4, LTE4).

Montelukast, Zafirlukast:

• Antagonist against LTD₄.

Ipratropium:

• An anticholinergic agent and derivative of atropine.

Question 819

Renin release by modified smooth muscle (juxtaglomerular) cells within the afferent glomerular arterioles. Chronic renal hypoperfusion can cause hyperplasia of the juxtaglomerular apparatus.

Question 820

Allergic bronchopulmonary aspergillosis due to Aspergillus fumigatus may complicate asthma.

Answer 820

ABPA can result in transient recurrent pulmonary infiltrate and eventually proximal bronchiectasis and eosinophilia.

Question 821

Medicare: Covers younger individuals with disabilities, ESRD, ALS

Answer 821

Medicaid: homeless, undocumented immigrants, pregnant women, and low-income families.

Question 822

Helps with multiple shoulder movements (extension, adduction, internal rotation).

• Originates from the spinous processes of T7-L5, the 9th-12th ribs, and the inferior angle of the scapular.
• Thoracordosal N.

Question 823

Decreases the breakdown of levodopa in peripheral tissues and increases the amount of levodopa available to cross the BBB:

• COMT inhibitors (Entacapone, Tolcapone)
• Dopa decarbxoylase inhibitors (Carbidopa) to decrease the peripheral formation of dopamine.

Answer 823

Dopamine agonists:

• Ergot compounds: Bromocriptine
• Nonergot compounds: pramipexole (PD) & ropinirole & pergolide.

Question 824

Dandy-Walker malformation:

• A developmental anomaly characterized by hypoplasia/absence of the cerebellar vermis and cystic dilation of the 4th ventricle with posterior fossa enlargement.

Answer 824

Chiari I: Herniation of cerebellar tonsils.

Chiari II: Herniation of cerebellar vermins.

Question 825

Quadriceps femoris

• Flexion of thigh & extension of leg (@ knee).
• Femoral nerve.
• Neuropathy: weakness involving the quadriceps muscle group and may have weakning of the iliopsoas with more proximal nerve injuires; often complain of difficutly with stairs and frequent falling secondary to “knee buckling”

Answer 825

The quadriceps tendon inserts at the superior pole of the patella and wraps distally around the patella to become the patellar tendon, which inserts at the tibial tuberosity.

Question 826

• Low back pain radiating to one or both legs
• Loss of anocutaneous reflex
• Saddle anesthesia
• Bowel and bladder dysfunction (S3-S5).
• Loss of ankle-jerk reflex with plantar flexion weakness

Answer 826

Lesion in S2-S4.

Question 827

1. PAO2 (alveolar): 104 mm Hg
2. PaO2 (arterial): ~ 100 mm Hg
3. Normal A-a gradient: 5-15 mm Hg.
   * The A-a gradient is normal with alveolar hypoventilation or inspiration of air at high altitude.
   * Common in patients with suppressed central respiratory drive (sedative overdose, sleep apnea) or those with diseases that decrease inspiratory capacity (MG, obesity).

Answer 827

Elevated alveolar to arterial graident (low PaO2 only):

• V/Q perfusion mismatch (eg. P.E., COPD).
• Diffusion impairment (Fibrosis).
• Right-to-left shunting.

Question 828

Side effects of fibrinolysis (e.g., tenecteplase, alteplase)

Answer 828

Intracranial hemorrhage:

• Decreased level of consciousness.
• Asymmetric pupils.
• Irregular breathing.

Question 829

HIV

Answer 829

• Pol* gene mutations: responsible for acquired resistance to HIV reverse transcriptase inhibitors and HIV protease inhibitors.
• Env* gene mutations: enable escape from host neutralizing antibodies.

Question 830

Vascular smooth muscle cells are stimulated to synthesize ECM (e.g., collagen, elastin, proteoglycans) that form the fibrous cap typical of mature atheromas.

Answer 830

Atherosclerosis is initiated by repetive endothelial cell injury, which leads to a chronic inflammaotry state in the underlying intima of large elastic arteries as well as large and medium-size muscular arteries.

Question 831

Osteoarthritis: osteophyte formation leading to bony enlargement of the DIP and PIP (heberden and bouchard nodes, respectively)

• Brief morning stiffness (<30 min).

Answer 831

Rheumatoid arthritis:

• Rheumatoid factor: IgM against Fc portion of IgG
• Anti-CCP (most specific).
• Affects PIP and MCP only.
• Longer morning stiffness > 1 hour.
• Cervical spine involvement: subluxation, cord compression.
• Tx: NSAIDs or glucocorticoid provide most rapid, temporary relief until DMARDs therapy can kick in.

Question 832

• Sudden back pain radiating to the foot
• Decreased ankle reflex.
• Positive straight leg raise test.

Answer 832

• Acute lumbosacral radiculopathy is most commonly caused by compression of the L5 or S1 nerve roots due to vertebral disc herniation.

Question 833

Determining the patient’s volume status and mesuring the urinary chloride concentration can help to identify the cause of metabolic alkaosis.

• Vomiting or nasogastric suctioning: loss of H⁺ and Cl^- ions
• Thiazide & loop diuretic use: block absorption of Na⁺ and Cl^- ions.
• Mineralocorticoid excess state.

Question 834

Organisms in the Mycoplasma genus, including Ureaplasma urealyticum, lack peptidoglycan cell walls; as a result, they’d be resistant to cell wall synthesis inhibitors (beta-lactams) such as penicillins, cephalosporins, carbapenems, vancomycin.

Answer 834

Beta-lactams work during exponential growth of cell walls:

• Penicillins and cephalosporins (eg, ceftriaxone) function by irreversibly binding to penicillin-binding proteins, such as transpeptidase.
• Vancomycin: Blocks D-ala-D-ala configuration.

Question 835

Major virulence factor of Hib is its polysaccharide capusle, which is composed of the polymer polyribosylribitol phosphate (PRP).

Question 836

Permissiveness: One hormone allows another to exert its maximal effect.

Additive: The combined effect of 2 drugs is equal to the sum of their individual effects.

Synergistic: The combined effect exceeds the sum of the individual drug effects.

Question 837

The acquisition of a new viral surface protein is often all that is necessary for a virus to infect a new type of host cell. What is phenotypic mixing ?

Answer 837

2 viruses infect the same cell and progeny viruses exhibit coat or envelope proteins not coded for by the genetic material packaged within them.

However, subsequent progeny express only the proteins encoded by their genome.

Question 838

Differential clubbing and cyanosis without blood pressure or pulse discrepancny are pathognomonic for a large PDA complicated by Eisenmenger syndrome (irreversible changes of pulmonary vessels).

• PDA delivers unoxygenated blood distal to the left subclavian artery.

Question 839

Aminoaciduria:

• Hereditary (autosomal recessive) condition in which Cystine-reabsorbing PCT transporter loses function, causing cystinuria.
• Also results in poor reabsorption of ornithine, lysine, and arginine.
• Associated with ↓ pH.

Question 840

Children with conduct disorder are at risk for developing antisocial personaltiy disorder as adults (> 18 y.o.)

• A persistent pattern of violating major societal norms or the rights of others
• Aggression toward people and animals, deceitfulness or theft, destruction of property, serious violation of rules.

Question 841

In combination with Epinephrine, propranolol will counteract Epi’s β2-mediated vasodilation and β1-mediated heart rate increase while leaving the α1 effect (vasoconstriction) intact.

• Net effect: Increased diastolic blood pressure and cause a reduction in heart rate.

Answer 841

α1: increases diastolic blood pressure (vasoconstriction)

β2: decreases diastolic blood pressure (vasodilation).

Question 842

Long thoracic nerve injury classically occurs during axillary lymph node dissection and results in paralysis of the serratus anterior msucle, leading to winging of the scapulae.

Answer 842

Serratus anterior:

• Originates as multiple branches from the side of the chest along the 1^st-8^th ribs and inserts along the entire length of the medial scapular border.

Question 843

• Barrel-shaped chest
• Exhalation through pursed lips
• ↑ AP diameter
• Flattened diaphragm
• ↑ Lung field lucency.

Answer 843

• Associated with smoking.
• Frequently in upper lobes.
• Imbalance of protease and antiprotease –> Destruction of alveolar walls –> ↑ lung compliance

Question 844

NRTIs: Must be phosphorylated within the host cell to form the functional triphosphate moeity.

• Emtricitabine
• Lamivudine
• Tenofovir
• Zidovudine(AZT): Does not have a 3’-OH group, making 3’-5’ phosphodiester bond formation impossible.

Answer 844

Abcavir contraindicated if patient has HLA_B*5701 due to ↑ risk of hypersensitivity.

Question 845

NNRTIs:

• Do not require activation via intracellular phosphorylation.
• The more common NNRTIs include nevirapine and efavirenz.
• ADRs: Life-threatening hepatic failure.

Question 846

What are the most important opsonins (coating proteins)?

Answer 846

IgG & C3b.

Question 847

• A neurodevelopmental disorder that occurs mainly in the girls.
• Normal development until age 5-18 months, followed by a loss of motor and language skills and the development of stereotypic hand movements.
• Deceleration of head growth.

Question 848

The tubular fluid/plasma ultrafiltrate value.

Answer 848

1. The concentration of PAH, creatinine, inulin, and urea increase as fluid runs along the proximal tubule.

• Lowest concentration @ bowman capsule.
• Active secretion.

2. Na⁺, K⁺ doesn’t fluctuate considerably.
3. Concentrations of bicarbonate, glucose, and AA decrease.
   * Active reabsorption.

Question 849

A patient has progressive dyspnea and orthopnea along with CXR findings:

Answer 849

1. Prominent cephalization of the pulmonary vessels
2. Perihilar alveolar edema
3. Blunting of costophrenic angles (pleural effusions).
4. Kerley B lines; short horizontal lines situated perpendicularly to the plerual surface that represent edema of the interlobular septa.
5. Precipitating factors:

• MI
• Severe HTN
• Valvular heart disease
• Arrhythmis (a-fib)
• Drug use (cocaine)

Question 850

The overall increase in staphylococcal bloodstream infection (S. aureus, coagulase-negative staphylococcal species) is most likely related to increased use of intravascular devices.

Question 851

Preventive measures of beta-hemoltyic gram-positive Cocci in chains that are bacitracin-resistant?

Answer 851

Intrapartum ampicillin.

Question 852

• Can’t See.
• Can’t Pee.
• Can’t Hear a buzzing Bee.

Answer 852

• A disorder of type IV collagen
• Frequently progresses to renal failure by age 40 and is associated with hearing loss and ocular abnormalities
• Lamellated BM with irregular thining and thickening (basket-weave appearance).

Question 853

Ringed sideroblasts

Answer 853

Formed from precipitation of mitochondrial iron granules in developing erythrocytes due to defects in the heme synthesis pathway, including enzymatic inhibition induced by lead poisoning.

Seen in bone marrow, but not in the peripheral blood smear.

Question 854

Mucormycosis:

• Caused by Mucor, Rhizopus, Absidia

Answer 854

• Very strongly associated with DKA & underlying immunosuppression (due to solid organ transplantation, hematologic malignancies, or glucocorticoid therapy)
• Affect paranasal sinuses
• Broad, nonseptate hyphae that branch at wide, often 90 angels.

Question 855

The lung is supplied by dual circulation from the pulmonary and bronchial systems (collateral circulation). As a result, lung infarction only rarely develops as a complication of PE.

Question 856

Granular eosinophilic “ground glass” appearance.

Answer 856

Hepatitis B virus does not have a cytotoxic effect itself; however, the presence of viral HbSAg and HbSAg on the cell surface stimulate the host’s cytotoxic CD8+ T-lymphocytes to destroy infected hepatocytes –> leading to elevated ALT/AST.

Question 857

The most highly oxygenated blood in the fetus is carried by the umbilical vein (adult remnant: ligamentum teres), which empties directly into the IVC via the ductus venosus.

Question 858

A patient that presents with fever, hemodynamic instability (low B.P.), tachypnea, and evidence of a UTI has urosepesis which is likely complicated by:

Answer 858

Acute Respiratory Distress Syndrome:

• Capillary damage and the leakage of protein and fluid into the alveolar space.
• Noncardiogenic pulmonary edema with a normal (6-12mm Hg) pulmonary capillary wedge pressure (PCWP).
• Also caused by pancreatitis, which is a major risk factor.

Question 859

Nitroprusside’s effects on the cardiac pressure-volume cycle:

Answer 859

Decreases left ventricular preload and afterload, alloiwng an adequate CO to be delievered at a lower LV end diastolic pressure.

Question 860

• Childhood arthritis seen in <12 years old
• Presents with daily spiking fevers, salmon-pink macular rash
• Uveitis
• Arthritis
• Leukocytosis, thrombocytosis, anemiae., ↑ESR & CRP.

Question 861

• Presence of ANA, rheumatoid factor, and anti-ribonucleoprotein antibodies : SS-A & SS-B (anti-La)
• Focal lymphocytic sialadenitis on labial salivary gland biopsy can confirm diagnosis.
• Inflammation of salivary gland due to obstruction, infection, or immune-mediated mechanisms.

Question 862

1. Dermatitis herpetiformis: Deposits of IgA at tips of dermal papillae.

• Usually occurs 4th-5th decades.
• Clusters of pruritic vesicles and plaques on the buttocks and extensor surface of the extremities.
  
  • Papulovesicular skin rash in groups with erosion and excoriations.

2. Villous atrophy, crypt hyperplasia, and intraepithelial lymphocyte infiltration (esp. in duodenal).
3. Elevated IgA anti-endomysial and anti-tissue transglutaminase antibodies.

Answer 862

~ Tropical spruce: infectious etiology.

Question 863

Developmental field defect: An initial embryonic disturbance leads to multiple malformations by disrupting the development of adjance tissues and structures within a particular region.

Question 864

• Productive cough for > 3 months in a year for > 2 consecutive years.

Answer 864

• Mucous gland enlargement with increased number of goblet cells (increasing mucuous production), and patchy squamous metaplasia of the bronchial mucosa.
• Reid index: thickness of mucosal gland layer ot thickness of wall between epithelium and cartilage.

Question 865

Confounding: Exposure-disease relationship is muddled by the effect of a confounding variable, an extraneous factor associated with both exposure and disease.

• After stratification by the confounding variable, no significant association is noted between exposure and the outcome within each stratum.
• Best controlled by matching (eg, age, race).

Answer 865

Effect modification: Effect of an exposure on an outcome is modified by another variable.

• The different strata will have different measure of association.

Question 866

• Hemoptysis, cough, night sweats, weight loss with a right upper lobe infiltrate on CXR.
• Immunocompromised (HIV, Jail).
• Can be stained via Ziehl-Nielsen.
• “Serpentine cords”: responsible for inactivating neutrophils, damaging mitochondria, and inducing release of TNF.

Question 867

• Rifampin
  
  • Inhibits DNA-dependent RNA polymerase;
  • Can cause body fluids (urine, tears) to turn red.
• Ethambutol
  
  • Inhibition of arabinosyl transferase (mycobacterial peptidoglycan cell wall synthesis)
  • Optic neuropathy (decreased visual acuity, central scotoma, color blindness).
• Isoniazid
  
  • Disrupts mycolic acid.
  • Monotherapy: rapid emergence of antibiotic resistance.
  • Directly hepatotoxic.
  • Non-expression of the catalase-peroxidase enzyme: resistance.
  • Metabolized by acetylation.

Question 868

Demyelination would decrease length constant, a measure of how far along an axon an electrical impulse can propagate.

(would increase the time constant and lead to slower impulse conduction).

Question 869

An elderly patient presents with fever, headache, myalgia, and malaise. Several days later, he presents with recurrente fever, dyspnea, and produtive cough. Dx?

Answer 869

Influenzae (viral infection) –> Superimposed bacterial penumoniae

• S. aureus.
• S. pneumoniae.
• H. influenzae.

Question 870

• 2,3-BPG is produced from 1,3-BPG by the enzyme bisphosphoglycerate mutase.
• This reaction bypasses an ATP-generating step of glycolysis, causing no net gain in ATP while still generating 2 molecules of pyruvates.

Question 871

Innervates the major forearm flexors (biceps brachii, brachialis) and coracobrachialis (flexes and adducts the arm) and provides sensory innervation to the lateral forearm.

Question 872

• Elevated IOP
• Abnormal visual field testing with decreased peripheral vision.
• Funduscopic examination: increased cup-to-disc ratio.

Answer 872

Tx:

• Timolol: Diminishes the secretion of aqueous humor by the ciliary epithelium.
• Cholinergic agonists: make the trabecular meshwork more accessible to outlfow of aqueous humour.
• Latanoprost: Uveoscleral pathway.

Question 873

• Progressive exertional dyspnea.
• Edema, ascites, elevated JVP with rapid ‘y’ descent,
• Prominent S4.
• Echo shows left atrial enlargement, left ventricular hypertrophy, and normal ejection fraction.

Answer 873

Diastolic heart failure due to restrictive cardiomyopathy.

• Endocardial thickening and noncompliant ventricular walls.
• Amyloidosis, sarcoidosis, hemochromatosis, endomyocardial fibrosis.
  
  • Amyloidosis: An amorphous and acellular pink material.
  • Congo red stain apple-green birefringence under polarized light microscopy.

Question 874

The lung apices extend above the level of the clavicle and first rib through the superior thoracic aperture.

Penetrating injury in this area may lead to pneumothorax, tension pneumothorax, or hemothorax.

Question 875

Phenylephrine: α₁ > α₂

Norepinephrine: α₁ > α₂ > β₁

• β_1: Gs;↑cAMP in cardiac myocytes.
• Hypotension, septic shock.

Epinephrine: β > α

• Anaphylaxis
• Asthma.

Isoproterenol: β₁ = β₂

Answer 875

Phentolamine

• Rversible α blocker

Phenoxybenazmie:

• Irreversible blockers for pheochromocytoma.

Question 876

17a-hydroxylase deficiency presents with ?

Answer 876

• ↑ Mineralocorticoids (↑BP, ↓K+)
• ↓ Cortisol, sex hormones
• XY: ambiguous genitalia, undescended tests
• XX: Lacks secondary sexual development.

Question 877

VSD

• A holosystolic murmur at the left lower sternal border.
• Accentuated by handgrip maneuver which increases systemic vascular resistance/ afterload.

Question 878

Mitral Regurgitation ?

Answer 878

• Diminished heart sound and an apical holosystolic murmur that radiates to the axillae best heard in the left lateral decubitus position.
• Decreasing left ventricular afterload necessary by arterial vasodilator therapy (e.g., nitroprusside).
• Related to MVP & chordae tendineae rupture (due to bacterial endocarditis & acute rheumatic heart disease).
  
  • Rheumatic heart disease still prevalent in developing countries (eg, Cambodia).
• Audible S3 gallop due to increased amount of blood reentering the left ventricle during diastole.

Question 879

• Holosystolic murmur best heard at the left 2nd & 3rd intercostal spaces.
• Murmur increases with inspiration.

Question 880

Mitral Stenosis

Answer 880

• Mid-diastolic, low-pitched, rumbling murmur that may begin with an opening snap (immediately following S2).
• Usually found in older individuals
• Chronic rheumatic heart disease (eg, middle-aged patients).
• Higher pressure causes the valve to open more forcefully; ↓ Interval between S2 and OS correlate with increased severity.

Question 881

A patient presents with following findings:

• HTN
• Weight gain
• Moon facies
• Abdominal striae & truncal obesity
• Buffalo hump
• skin changes
• Hirsutism
• Osteoporosis
• Hyperglycemiae
• Immunosuppression

Answer 881

1. Measure serum ACTH
2. If ↓, suspect adrenal tumor or exogenous glucocorticoids
3. If ↑, distinguish between Cushing disease and ectopic ACTH secretion (eg., from small cell lung cancer) using high-dose dexamethasone suppression test.

Question 882

Defective G-coupled Ca²⁺ sensing receptors in multiple tissues (eg, parathyroids, kidneys). Higher than normal Ca²⁺ levels required to suppress PTH. Excessive Renal Ca²⁺ reuptake

• Mild hypercalcemiae
• Hypocalciuria
• Normal to ↑ PTH levels.

Question 883

• Pramlintide, Exenatide, liraglutide
  
  • ↓ Glucagon release
  • ↓ Gastric emptying
  • ↑ Satiety
  • ADR: hypoglycemiae.

Answer 883

• DPP4- inhibitors: Linagliptin, saxagliptin, sitagliptin

Question 884

Best course of action if there’s a reason to susepct abuse or neglect?

Answer 884

Patient should be interviewed alone:

• Even cognitively impaired adults can frequently communicate useful information about their quality of care.
  *

Question 885

PD-1 (Programmed death receptor-1) ?

Answer 885

Monoclonal antibodies block a specific cell surface receptor found on T lymphocytes to facilitate destruction of cancer cells by T cells.

Question 886

CD28 is a T cell-specific surface protein that interacts with B7 on APCs, providing costimulatory signal necessary for T cell activation.

Answer 886

CTLA-4 also binds to B7 but has an inhibitory function on activated T cells.

Question 887

• Young obese woman with daily headache, bilaterally symmetric papilledema, transient visual disturbances related to impaired cerebral venous outflow and elevated ICP.
• Impairs axoplasmic flow within the optic nerves —> causing bilateral optic disc edema.

Answer 887

Question 888

Most of the K+ filtered by the glomerulus is reabsorbed in the PCT and thick ascending loop of Henle.

The late distal and cortical collecting tubules are the primary sites for regulation of K concentration in the urine.

• Principal cells secrete K+ under condition of normal or increased K+ load.
• K+ depletion stimulates α-intercalated cells to reabsorb extra potassium.

Question 889

• Sudden upward jerking of the arm at the shoulder can cause injury to the lower trunk of the brachial plexus.

Answer 889

Carries nerve fibers from C8 and T1 spinal levels that ultimately contribute to the median and ulnar nervs–> may cause paralysis of all the intrinsic hand muscles

Question 890

Most ( >80%) coagulase-negative staphylococci (eg, S. epidermidis) are methicillin-resistant. Therefore, particularly with nosocomial infection, CoNS should be assumed to be methicillin-resistant until proven otherwise & vancomycin should be a component of initial therapy.

Answer 890

Later can be switched to nafcillin or oxacilin.

Question 891

Herpesviridiae (eg, CMV) bud through & acquire the lipid bilayer envelope from the host cell nuclear membrane.

Question 892

P=2T/R

• Smaller the radius, greater the distending pressure (the pressure required to keep a sphere distended).

Answer 892

Physiologically, surfactant helps to prevent smaller alveoli from collapsing during expiration, and assists in regulating alveolar expansion during inspiration to ensure that all alveoli expand at similar rates

Question 893

In a cross-sectional study, exposure and outcome are measured simultaneously at a particular point of time. (“SNAPSHOT STUDY”)

Question 894

1. Gram-negative diplococci: transmitted by direct contact with contaminated respiratory secretions or aerosolized droplets.
   * Meningitis
2. Prophylactic antibiotic (Rifampin) necessary.
3. The meningococcal vaccine contains capsular polysaccharides from major serotypes of N. meningitidis .

Question 895

The vagus nerve provides cutaneous sensation to the posterior external auditory canal via its small auricualr branch. An otoscope speculum can cause vasovagal syncope.

Answer 895

Sesnation to the rest of the canal is from the mandibular division of the trigeminal nerve.

Question 896

Thiazide and loop diuretics cause significant volume depletion, activating the RAAS system, which can lead to hypokalemia and (contraction) metabolic alkalosis

Answer 896

• Thiazide diuretics are more likely to cause hyponatremia and hypercalcemia
• Loop diruetics cause hypocalcemiae.
  
  • Also stimulates renal PG release, increasing RBF leading to increased GFR and enahcned drug delivery <—> NSAIDs.
  • OTOTOXICITY
  • Hypokalemiae: Gradual/progressive fatigue, myalgias, muscle cramp & weakness.

Question 897

(Carrier frequency of female) X (Carrier frequency of male) X (Probabiltiy of giving allele of interest)

• In autosomal recessive (eg, CF), there’s 25% change of giving recessive allele to an offspring.
• In rare autosomal recessive disease, P equals 1.

Question ID: 11835

Question 898

Positive selection: Occurs in the thymic cortex and involves interaction of T cells with thymic cortical epithelial cells expressing self MHC.

Answer 898

Negative selection: Occurs in the thymic medulla and involves interaction of the developing T cells with thymic medullary epithelial and dendritic cells.

• Elimiate T cells that may be overly autoreactive aganist self antigens and therefore may play a role in autoimmunity if not destroyed.

Question 899

Cheyne-Strokes breathing?

Answer 899

CHF.

Question 900

Folate deficiency ?

Answer 900

Inhibits the synthesis of nucleic acids, particularly the formation of deoxythymidine monophosphate (dTMP). This leads to defective DNA synthesis that characteristically causes increased apoptosis of hematopoeitc cells and megaloblastic anemiae.

Question 901

The AV node refractory period regulates the number of atrial impulses that reach the ventricle and determines the ventricular contraction rate in conditions where the atria undergo rapid depolarization.

Answer 901

In case of complete heart block (3rd degree), SA node impulses cause atrial contraction while impulses generated by the AV node causes ventricular contraction (bradycardia; rate of 45-55bpm)

Question 902

Cavernous sinus thrombosis:

Answer 902

Infection of the medial face, sinuses (ethmoidal or sphenoidal), or teeth may spread through the vaveless facial venous system into the cavernous sinus, resulting in caverous sinus thrombosis:

Affects CN III, IV, VI, V_1,2

Answer 903

Question 904

Leukemoid reaction is a benign leukocytosis (>50,000/mm3) that occurs in response to an underlying condition such as severe infection/hemorrhage, malignancy, or acute hemolysis.

• Leukocyte alkaline phosphatase levels are normal or increased.
• Peripheral smear: Increased bands, early mature neutrophil precursors (eg, myelocytes), and granules (eg, Dohle bodies) in the neutrophils.

Answer 904

Question 905

1. Obsessions:
   * Recurrent, intrusive, anxiety-provoking thoughts, urges, or image
2. Compulsion:
   * Response to obsessions with repeated behaviors or mental acts and behaviors not connected realistically with preventing feared events.
3. Time-consuming (>1 hr/day) or causing significant distress.
4. Tx: SSRI & CBT.

Question 906

Deep intraparenchymal hemorrhage is most commonly caused by hypertensive vasculopathy of the small penetration branches of the cerebral arteries

• Charcot-Bouchard aneurysm rupture: the most frequently affected locations include the basal ganglia (putamen), cerebellar nuclei, thalamus, and pons.
  
  • The basal ganglia are supplied by the lenticulostriate arteries, which are small vessel branches off the middle cerebral artery.

Answer 906

• Intraparenchymal hemorrhage within deep brain structures, which would appear acutely as a relatively large intracerebral hyperdensity on CT scan.
  *

Question 907

S3:

• Ventricular gallop sound (shortly after S2) best heard when the patient lies in the left lateral decubitus position @ END EXPIRATION
• Heard during rapid passive filling of ventricles in diastole.
• Sudden cessation of filling as ventricle reaches it elastic limit (secondary to ventricular volume overload or enlargement).
• Associated with systolic dysfunction (eg, dilated cardiomyopathy).

Answer 907

S4:

• Atrial gallop sound (before S1)
• Heard immediatley after atrial contraction as blood is forced into a stiff ventricle.
• Associated with diastolic dysfunction (LVH).
  
  • Left ventricular hypertrophy following HTN.

Question 908

Francisella tularensis causes tularemia, a zoonotic infection that can occur following ocntact with lagomorphs and rodents (eg, rabbits, beavers, squirrels).

Answer 908

Q fever is caused by Coxiella burnetti

• Inhalation of bacteria from air contaminated by animal wastes.
• Nonspecific febrile illness with severe debilitating headaches.
• Pneumoniae with lobar consolidation.
• Thrombocytopeniae.

Question 909

Superior oblique muscle

• Deficiency: vertical diplopia, which is most noticeable when the affected eye looks down and toward the nose (up-close reading, walking down stairs).

Question 910

How is end-spectrum beta lactamse (ESBL) gene transmitted ?

Answer 910

ESBL can be produced by gram-negative bacteria, rendering cephalosporin and other beta-lactam antibiotics inactive. These genes can be transmitted between organisms through plasmid conjugation.

Question 911

Wallerian Degeration

Answer 911

Process of axonal degeneration and breakdown of the myelin sheath that occurs distal to a site of injury.

Axonal regeneration does not occur in the CNS due to the persistence of myelin debris, secretin of neuronal inhibitory factors, and development of dense glial scarring.

Question 912

Cholesteatomas are collections of sqaumous cell debris that from a round, pearly mass behind the tympanic membrane in the middle ear.

Can erode through auditory ossicles, causing conductive hearing loss.

Question 913

Moderate increases in capillary fluid transudation (eg, cor pulmonale secondary to COPD) can be offset by a compensatory increase in tissue lymphatics drainage that occurs due to increased interstitial fluid pressure.

Question 914

0-15°: Supraspinatus (Suprascapular N)

• Empty can test.

15-100°: Deltoid (Axillary N)

> 90°: Trapezius (Accessory N)

• Drooping of the shoulder
• Impaired abduction of the arm above horizontal line & winging of the scapulae.
• Vulnerable to injury in posterior triangle of the neck.

> 100°: Serratus anterior (Long thoracic N)

• Impaired arm abduction and winging of the scapulae.

Question 915

The right middle lobe of the lung lies immediately adjacent ot the right border of the heart, and any condition that increases radiographic density in the right middle lobe will obscure the adjacent cardiac silhouette.

Question 916

Transketolase, an eyzme of the nonoxidative branch, is responsible in part for the interconversion of ribose-5-phosphate (nucleotide precursor) and fructose-6-phosphate (glycolytic intermediate).

• Uses thiamine as a cofactor to shuttle 2-carbon fragments between sugar molecules.

Answer 916

The pentose phosphate pathway consists of an oxidative (irreversible)branch and a nonoxidative (reversible) branch, and each can function independelty based on cellular requirements.

• CYTOSOL.

Question 917

Herediatry angioedema:

Answer 917

Active kallikrein and bradykinin levels are increased due to lack of C1 esterase inhibitor.

Question 918

Pressure in the left renal vein may become elevated due to compression where the vein crosses the aorta beneath the SMA. This “nutcracker effect” can cause hematuria and flank pain.

Question 919

Vomiting center is located ?

Answer 919

CTZ located on the dorsal surface of the medullae at the caudal end of the 4th ventricle in a region known as the area postrema.

Question 920

Drugs that have been shown to improve long-term survival in patients with heart failure due to left ventricular systolic dysfunction include ?

Answer 920

• BB (eg, cavediolol & labetalol)
• ACEI
• ARB
• Aldosterone antagonists.

CARDIOPROTECTIVE & PREVENT DELETERIOUS CARDIAC REMODELING.

Question 921

1. Annular pancreas
   * Abnormal rotation of ventral pancreatic bud forms a ring of pancreatic tissue —–> encircles 2nd part of duodenum; may cause duodenal narrowing and vomtiing.
2. Pancreas divisum:

• Ventral and dorsal parts fail to fuse at 8 weeks. Common anomaly; most asymptomatic, but may cause chronic abdominal pain and/or pancreatitis.
• Ventral: main pancreatic duct.

3. Spleen: arises in mesentry of stomach (hence is mesodermal) but has foregut supply (celiac trunk–> splenic artery).

Answer 921

Question 922

Diaphragmatic hernia

Answer 922

• Congenital defect of pleuroperitoneal membrane.

Question 923

Indirect inguinal hernias

Answer 923

• Intermittent bulge in the groin that presents when an infant cries/strains; failure of processus vaginalis to close, forming hydrocele.
• Goes through internal (deep) inguinal ring, external (superficial) inguinal ring, and into the scrotum.
• Covered by all 3 layers of spermatic fascia: ICE TIE
• Lateral to epigastric vessels.

Question 924

Direct inguinal hernias

Answer 924

• Covered by external spermatic fascia (external oblique) only.
• Usually in older men, due to an acquired weakness in the transversalis fascia.
• Medial to inferior epigastric vessels within Hesselbach triangle.

Question 925

Femoral hernia

Answer 925

• Protrudes below inguinal ligament through femoral canal below and lateral to pubic tubercle (Medial to femoral vessels).
• More common in females.

Question 926

1. Secretin function?

• Produced from S cells (duodenum)
• ↑ Pancreatic HCO₃^- secretion
• ↓ Gastric acid secretion
• ↑ bile secretion.

2. Oral glucose load leads to ↑insulin compared to IV equivalent due to GIP (eg, gastric inhibitory peptide) secretion.
3. VIP: Watery Diarrhea, Hypokalemia, and Achlorhydria (WDHA syndrome).

Question 927

Malabsorption syndromes:

• diarrhea, steatorrhea, weight loss, weakness, vitamin and mineral deficiencies.
• Screen for fecal fat (eg, Sudan stain).

Answer 927

1. Lactose intolerance:

• Normal-appearing villi.
• Osmotic diarrhea with ↓ stool pH (colonic bacteria ferment lactose).
• (+) Lactose hydrogen breath test.

2. Tropical spruce:

• Similar findings as celiac spruce, but responds to antibiotics
• Megaloblastic anemiae due to folate & B12 deficiency.

3. Whipple disease:

• PAS: stains for glycoprotein.
• Infection with T. whipplei (intracellular gram (+) bacteriae); foamy macrophages in intestinal lamina propria
• Caridac symptoms, arthralgias, and neurololgic symptoms.
• Tx: Antibiotics.

Question 928

A result is considered statistically significant if the 95% CI does not cross the null value, which corresponds to a p-value < 0.05

Question 929

The presence of fluid in the pulmonary interstitium causes distortion (swelling) of the affected tissue, increasing resistance to movement (decreased lung compliance).

Answer 929

As a result, the negative pressure generated during normal inspiratory effort is not sufficient to adequately distend the lung, resulting in poor gas exchange and shortness of breath.

Question 930

The pO2 in the left atrium and ventricles is lower than that in the pulmonary capillaries due to mixing of oxygenated blood from the pulmonary veins with deoxygenated blood from the bronchial circulation and thebesian veins.

Question 931

Photoaging is a product of excess exposure to UVA wavelenghts and is characterized by epidermal atorphy with flattening of rete ridges.

Answer 931

In addition, there’s a decreased collagen fibril production and increased degradation of collagen and elastin in the dermis.

Question 932

Pulmonary vascular resistance is lowest at the FRC.

• Increased lung volumes increase PVR due to the longitudinal stretching of alveolar capillaries by the expanding alveoli.
• Decreased lung volumes also increase PVR due to decreased radial traction from adjacent tissues on the large extra-alveolar vessels.

Question 933

Cytoplasmic P bodies play an important role in mRNA translation regulation and mRNA degradation:

Question 934

The H. influenzae serotype B vaccine consists of a capsular polysaccharide conjugated to a carrier protein (tetanus toxoid) protein or outer membrane protein [OMP] of N. meningitidis.

Answer 934

Protein conjugation causes a T cell-mediated immune response leading to long-term immunity through production of memory B-lymphocytes.

Question 935

1. Gram (+) anaerobic bacteria: characteristic sulfur granules.
2. Most frequently leads to the formation of cervicofacial abscesses, but systemic infection can develop anywhere in the body when the mucosa is disrupted (eg, pulmonary)
   * Bacteria with unique filamentous, branching patterns and the characteristic sulfur granules, which are formed by calcified mycelial fragments.
3. Tx: Penicillin

Answer 935

Question 936

Recombination: Refers to the exchange of genes between 2 (nonsegmented) chromosomes via crossing over within homologous region. The resulting progeny can have recombined genomes with traits from both parent viruses.

Answer 936

Reassortment refers to changes in genetic composition that occur when host cells are coinfected with 2 segmented viruses that exchange whole genome segment.

• eg) Orthomyxoviridae.

Question 937

Restless leg syndrome

Answer 937

1. Uncomfortable urge to move the legs with:

• Unpleasant sensations in the legs
• Onset with inactivity or at night
• Relief with movement (eg, walking, stretching)

2. Tx: Dopamine agonist (eg, pramipexole)

Question 938

What’s the major determinant of whether or not a coronary artery plaque will cause ischemic myocaridal injury?

Answer 938

Rate at which it occludes the involved artery. A slowly developing occlusion would allow for formation of collaterals that could prevent myocardial necrosis.

A thin fibrous cap, a rich lipid core, and active inflammation in the atheroma would decrease plaque stability and thus potentially promote rapid coronary occlusion via superimposed thrombosis if the plaque were to rupture.

Question 939

Atropine blocks vagal influence on the SA and AV nodes and is effective in increasing heart rate in such patients.

Answer 939

In the eye, atropine causes mydriasis, resulting in narrowing of the anterior chamber angle and diminished outflow of aqueous humour. This can precipitate angle-closure glaucoma, which presents with unilateral severe eye pain and visual disturbances (eg, halos).

Question 940

Mycoplasma pneumoniae

Answer 940

1. Walking pneumoniae: Typically mild with bilateral infiltrates on CXR appearing more severe than expected based on clinical findings.
2. Cold agglutinin: Auto-immune hemolytic anemiae.
3. Lacks cell wall; cannot be stained.

Question 941

• Cerebellar ataxia (spinocerebellar tract degeneration).
• Loss of positon/vibration sensation (DCML degeneration).
• Kyphoscolisos and foot abnormalities (pes cavus).
• Diabetes mellitus.
• Hypertrophic cardiomyopathy: Most common cause of death.

Answer 941

Mutation of the frataxin (FXN) gene, which codes for an essential mitochondrial protein involved in the assembly of iron-sulfur enzymes.

*

Question 942

Mycobacterium avium complex

Answer 942

1. CD4+ count < 50 cells/ uL
2. Typically presents with nonspecific symptoms of fever, weight loss, and diarrhea in an HIV+ patient.
3. Prophylaxis: Azithromycin.

Question 943

ADCC:

Defense against parasitic infections: When a parasite enters the bloodstream. it is bound by free IgE. The resultant antigen-antibody complex then binds an IgE Fc receptor located on the eosinophil cell surface. Upon binding, the eosinophil releases major basic protein and other enzymes from its granules.

Question 944

The PI3K/Akt/mTOR pathway is an intracellular signaling pathway inmportant for anti-apoptosis, cellular proliferation, and angiogenesis.

Question 945

1. Risk for avascular necrosis and nonunion.
2. Persistent wrist pain and tenderness in the anatomical snuffbox.

Question 946

Chronic AV fistula would cause?

• A decreased TPR: Increased slope of both the cardiac function curve and the venous return curve.
• Increased mean systemic pressure: Rightward shift of the venous return curve along the X-axis.

Answer 946

Phe infusion:

• Increases sympathetic tone resulting in vasoconstriction and an increase in TPR: decreased cardiac output due to increased afterload along with decreased venos return.

Question 947

1. Etiology:

• Idiopathic or viral pericarditis.
• Cardiac surgery or radiation therapy.
• Tuberculosis.

2. Pathogenesis:
   * Thickened, rigid pericardium forms a noncompliant casing surrouding the heart, limiting ventricular expansion during diastolic filling.

Answer 947

3. Hemodynamic signs:

• Kussmaul sign ***
• Pulsus paradoxus.
• Friction rub Percardial knock.

Question 948

1. Progressive development of spastic diplegia, abnormal movements, and growth delay in the setting of elevated arginine levels.
2. Dx: elevated arginine levels on plasma amino acid testing
3. Tx: low-protein diet devoid of arginine.

Answer 948

Question 949

1. Typically result in truncal ataxia, characterized by a wide-based, unsteady gaint & rhythmic, postural trmor of the fingers and hands.
2. May also develop vertigo and nystagmus due to involvement of the inferior vermis and the flocculonodular lobe, which modulate balance and ocular movements via connectiosn with the vestibular nuclei and MLF.

Question 950

A unilateral vesicular rash localized on a single dermatome in an elderly patient is most likely herpes zoster.

Answer 950

PHN is the most common neurologic complication of VZV infection.

Question 951

Amifostine?

Answer 951

A cytoprotective free-radical scavenger used to decrease nephrotoxicity associated with platinum-containing and alkylating chemotherapeutic agents and to decrease xerostomia (dry mouth).

Question 952

Most chemical carcinogens enter the body in an inactive state (pro-carcinogens).

These pro-carcinogens are converted into active metabolites by the cytochrome p450 monooxygenase system.

Answer 952

Individual susceptibility to chemical carcinogens depend on the activity of these p450 enzymes, which is genetically determined.

Question 953

In experiments, transient myocardial ischemia causes myocardial cells to increase in size. This effect is due in part to ?

Answer 953

Failure of the sarcoplasmic reticulum Ca²⁺-ATPases, leading to increased intracellular Na⁺ and Ca²⁺ and increased intramitochondrial Ca²⁺ concentration that attract free water.

Question 954

• Posterior to the medial epicondyle
• Innervates the flexor carpi ulnaris and the median portion of the flexor digitorum profundus.
• Wrist: Hook of the hamate & Pisiform bone within Guyon’s canal

Answer 954

Weakness in:

• Wrist flexion/adduction
• Finger abduction/adduction
• Flexion of the 4th/5th digits.
• Hypothenar eminence can appear flattened due to denervated muscle atrophy.

Question 955

Estrogen- or progesterone-receptor positivity in breast cancer indicated expected sensitivity to tamoxifen and aromatase inhibitor Tx.

Answer 955

HER2 overexpression suggests a more aggressive tumor that typically responds to therapy with the anti-HER2 monoclonal antibody trastuzumab.

• Tyrosine kinase activity ***

Question 956

Examination of the lower extremities shows dilated, tortuous veins at the calves and ankles bilaterally, with no erythema or edema.

Answer 956

Varicose veins - dilated, tortuous veins typically involving the superficial venous drainage (vs. DVT).

• Most common in patients age > 50.
• Risk increased by conditions that cause elevated venous pressure (eg, prolonged standing, prengnancy, obesity).
• Common complications: chronic edema, stasis dermatitis, skin ulcerations, poor wound healing.

Question 957

Radial nerve can be injured at:

1. Mid shaft of humerus
2. supracondylar humeral fracture with anterolateral displacement of the proximal fracture fragment

Answer 957

Radial nerve (+deep brachial artery –> radial brachial artery)

• Inability to extend the wrist and MCP of all digits.
• Posterior cutaneous hand except for the distal digits and the last one and a half fingers.
• Sparing of the triceps brachii.

Question 958

Supracondylar fractures resulting in anteromedial displacement of the proximal fracture (Median nerve + brachial artery).

Answer 958

• Sensory loss over the first 3 digits.
• Weakness on thumb flexion/opposition
• Flexion of the second/third digits
• Wrist flexion/abduction.

Question 959

B_6: pyridoxine phosphate

Answer 959

1. Serves as an essential cofactor for transaminase (eg, glutamate reacts with oxaloacetate to form aspartate and a-ketoglutarate).
2. Deficiency:

• Peripheral neuropathy; can be precipitated by isoniazid.
• A cofactor for G-ALA synthase, the enzyme that catalyzes the rate-limiting step in heme synthesis; inhibition produces microcytic, hypochromic anemiae.

Question 960

HSV-2

Answer 960

Genital herpes:

• Multiple painful genital ulcers (with a characteristic erythematous base/ vesicles may or may not be present).
• Systmic symptoms (eg, fever, myalgia)
• Inguinal lymphadenopathy.
• Lies dormant in sacral ganglia –> recurrent genital lesions.
• Erythema multiforme.
• Viral DNA PCR & Tzanck smear.

Question 961

Type II hypersensitivity

Answer 961

• IgG binds to an antigen on the surface of target cells, leading to complement activation, ADCC, or phagocytosis.
  
  • Goodpasture syndrome.
  • Autoimmune hemolytic anemia.
  • Acute hemolytic transfusion reaction.

Question 962

• Fever, arthralgias, and pruritic skin rash begin 7-14 days after exposure to an antigen (eg, drugs).
• Small vessel vasculitis with fibrinoid necrosis and intense neutrophil infiltration.

Answer 962

1. Serum sickness (Caused by drugs acting as haptens):

• Deposition of IgG and/or IgM complement-fixing antibodies result in localized complement consumption and hypocomplementemia.
• Type III hypersensitivity:
  
  • Deposition of antibody-antigen complexes.
  • Complement activation.
  • PSGN.
  • SLE.

Question 963

Type IV hypersensitivity:

Answer 963

Helper T cells (usually of the T_H1 lineages) and macrophage:

• TB skin test & Candida extract skin reaction.
• Allegic contact dermatitis
  
  • Poison ivy: Involvement of exposed skin and a linear or streaky pattern where the skin brushed against the plant.
  • Nickel allergy.
• Acute & chronic transplant rejectoin.
• GVH.

Question 964

Alcoholic hepatitis

Answer 964

1. Requires sustained, long-term consumption.
2. Swollen and necrotic hepatocytes with neutrophilic infiltration
3. Mallory bodies (intracytoplasmic eosinophilic inclusion of damaged keratin filaments).
4. AST > ALT (usually 2:1).

Question 965

Metoclopramide

Answer 965

1. D₂ receptor antagonist:
   * ↑ resting tone, contractility, LES tone, motility, promotes gastric emptying.
2. Diabetic & postsurgery gastroparesis, antiemetic, persistent GERD.
3. ↑ Parknsonian effects, tardive dyskinesia: contraindicated in Parkinsonian patients.

Question 966

Hand hygiene by health care workers is the single most important measure to reduce the risk of transmission of microorganisms between patients.

Question 967

ST elevations:

Answer 967

Leads V5-V6, I, aVL:

• Lateral M.I. due to occlusion of the left circumflex artery.

Leads V1-V4:

• Anterior aspect due to occlusion of LAD

Leads I, aVL, V1-V6:

• Left coronary artery

Leads II, III, aVF:

• Posterior asepct due to occlusion of RCA.
• RCA most commonly supplies SA, AV nodes (unless patient is left dominant).

Question 968

Frequent site of ablation for a-fib?

Answer 968

AV node; located on the endocardial surface of the right atrium, near the insertion of the septal leaflet of the tricuspid valve and the orifice of the coronary sinus.

Question 969

Sporothrix schenckii

Answer 969

Typically acquired by diret skin inoculation [scrapes from rose bushes]

Biopsy of the lesion reveals a granuloma consisting of histiocytes, multinucleated giant cells, and neutrophils, surrounded by plasma cells.

From the site of incoulation, the fungus spreads along the lympathics, forming subcutaneous noduels and ulcers.

Question 970

• Pain on weight bearing.
• Decreased range of motion.
• No swelling, erythema, or warmth in the surrounding area.

Answer 970

• Femoral head usually affected (medial circumflex artery).
• Causes include:
  
  • SCD.
  • Glucocorticoid therapy.
  • Vasculitis.
  • Alcoholism.

Question 971

• A hallmark of cell injury and death.
• Occurs in all types of necrosis (eg, coagulative, fat, caseous, liquefactive) in the setting of normal calcium levels.
• Deposits that devleop lamellated outer layers: Psammomma bodies.

Question 972

Role of clavulanic acid, sulbactam and tazobactam?

Answer 972

Beta-lactamse inhibitors; expands antibiotics spectrum of activity to include strains of B-lactamse synthesizing bacteria that are resistant to antibiotics alone.s

Question 973

BPH leads to intermitten bladder outlet obstruction and overflow incontinence

Answer 973

Urinary retention results in increased pressure in the urinary tract and resultant reflux nephropathy.

• hydronephrosis and renal interstitial atrophy and scarring ensue.

Question 974

Aprepitant?

Answer 974

NK1 receptor antagonists; prevent substance P release; prevent both acute vomiting & delayed emesis associated with chemotherapy.

Question 975

MOA of antifungal medications?

Answer 975

1. Amphotericin B & nystatin

• Binds ergosterol in the fungal cell membrane and leads to pore formation and cell lysis.
• Synergistic agent: Flucytosine.

2. -azoles:

• Inhibit ergosterol synthesis.
• P450 inhibitor.

3. Casofungin & echinocandin
   * Blocks synthesis of 1,3-beta-D-glucan of the fungal cell wall.
4. Griseofulvin:

• P450 inducer.
• Binds microtubules & inhibiting mitosis.

Question 976

A lesion in the optic tract:

Answer 976

Can produce contralateral homonymous hemianopia and a relative afferent pupillary defect (Marcus Gunn) in the pupil contralateral to the tract lesion.

• Since nasal portion of (contralateral) retina contributes more.

This defect can be observed during the swinging flashlight test because the patient’s pupil constrict less (and therefore appear to dilate) when a bright light is swung to the pupil contralateral to the tract lesion.

Question 977

________ would increase dihydrofolate reductase and DNA polymerase ?

Answer 977

Rb protein phosphorylation, rendering it inactive –> Release E2F, which allows the cell to progress through the G1–>S checkpoint.

Question 978

• High-grade fever.
• Recent IV drug use.
• Septic emboli from tricuspid endocarditis (esp. from Staphylococcus aureus).

Answer 978

Lung autopsy:

• Multiple wedge-shaped hemorrhagic lesions in the periphery of the lung, which are most likely due to pulmonary (septic in this case) emboli.
• Because there’s dual blood supply to the lungs (eg, pulmonary and bronchial arteries), patients with pulmonary emboli typically develop hemorrhagic infarction as opposed to ischemic infarction.

Question 979

Ecchymosis:

• Frequently indicate a deep hemorrhage (hematoma) due to bony fracture, ligamentous rupture, or muscular injury
• Do not blanch under pressure because the RBCs are not contained within the vasculature
• At least < 1 cm in diameter.

Question 980

Attributable risk percent in the exposed (ARP_exposed )

Answer 980

100 X [(RR-1)/RR]

RR= relative risk.

Question 981

Down syndrome RFLP:

Answer 981

The fact that the child received 2 different bands from the mother indicates that he inherited both of her homologous chromosomes. Thus, the problem occurred in the mother during meiosis I, when homologus chromosomes are separated.

Question 982

Who is appropriate to obtain informed consent?

Answer 982

By a provider who has sufficient knoweldge to give an accurate description of the intervention, the risks and benefits of treatment, and available alternative treatmetns and to answer all of the patient’s questions.

Question 983

Beta-endorphin shares a molecular origin with?

Answer 983

ACTH and MSH from POMC.

Question 984

How does carotid sinus work for sudden onset of palpitations and rapid regular tachycardia that’s consistent with PSVT?

Answer 984

• Leads to increased afferent firing from the carotid sinus via CN IX (glossopharyngeal nerve) to the vagal nuclues & medullary centers.
• Increases efferent vagal parasympathetic tone.
• Slows conduction through the AV node and prolongs the AV node refractory period.

Question 985

Pyruvate kinase deficiency:

Answer 985

Disrupted glycolytic pathway leading to insufficient ATP production –>

Splenic hyperplasia results from increased work of the splenic parenchyma, which must remove these deformed erythrocytes from the circulation.

Question 986

For patients with stiff lungs (increased elastic resistance), the work of breathing is minimized when the respiratory rate is high and the tidal volume is low.

Question 987

Hemodynamic findings following an ST-segment elevations in leads II, III, aVF.

Answer 987

The dominant right coronary artery perfuses both the inferior wall of the left ventricle and the majority of the right ventricle –> Right Ventricular infarction.

• Clear lungs on auscultation.
• Diminished LV filling & C.O.
• Dimished PCWP
• Elevated central venous pressure due to impaired forward flow and backup of blood into the systemic venous systme.

Question 988

• Women aged 20-40.
• Severe right ventricular hypertrophy in a young woman with progressive dyspnea and sudden death.
  
  • Holosystolic murmur that increases with inspiration of tricupsid regurgitation is present.

Answer 988

1. Vasoconstriction with vascular smooth muscle proliferation, intimal thickening and fibroiss, increased pulmonary vascular resistance, and progressive pulmonary hypertension.

• Accentuation of the pulmonary componenet of the second heart sound (P2).
• Can lead to right ventricular hypertrophy/failure.

2. Most often caused by inactivating mutations involving the pro-apoptotic BMPR2 gene.
3. Tx: Bosentan : Endothelin-receptor antagonist; vasodilator

Question 989

1. AV concentration gradient is an indirect measurement of the solubility of the anesthetic in body tissues.
   * High tissue solubility are characterized by large AV concentration gradients and slower onset of action.
2. Drugs with high blood/gas partition coefficients are more soluble in the blood, demonstrate slower equilibration with the brain, and have longer onset times.

Answer 989

The lower the MAC (minimal alveolar concentration), the more potent the anesthetic.

Question 990

Communicating hydrocephalus:

Answer 990

Usually occurs secondary to dysfunction or obliteration of subarachnoid villi (sequelae of meningeal infections): all ventriculi are symmetrically enlarged.

Question 991

Yellow Fever?

Answer 991

• High fever.
• Black vomitus (dark-colored blood in the vomitus)
• Jaundice
• Liver biopsy: signs of Councilman bodies (acidophilic inclusions in liver).

Question 992

Berylliosis

Answer 992

• Beryllium in aerospace and manufacturing industreis.
• Granulomatous (noncaseating) on histology.

Question 993

Coal-worker’s Pneumoconiosis

Answer 993

• Prolonged coal dust exposure–> Macrophages laden with carbon–> Inflammation and fibrosis
• Macrophages primarily responsible for clearing particles from respiratory bronchioles and alveolar ducts.
  
  • Trachea, bronchi, terminal bronchioles: mucociliary transport.

Question 994

Silicosis

Answer 994

• Foundries, sand blasting, wood-chopping, mines
• Silica may disrupt phagolysosome and impair macrophages, increasing susceptibility to TB.
• Birefringent silica particles surrounded by fibrous tissue.
• “Eggshell “ calcification of hilar lymph nodes on CXR.

Question 995

MMP?

Answer 995

Zinc-containing enzymes that degrade the ECM. They parcitipate in normal tissue remodeling and in tumor invasion through the BM and CT.

Question 996

The depletion of ATP in crticial cellular areas and the accumulation of toxins reuslt in loss of contractility within about … ?

Answer 996

60 seconds of total myocardial ischemiae.

> 30 minutes of total myocardial ischemiae, about half of the cellular adenine stores are lost (adenosine can act as vasodilators); at this point, failure of cellular homoeostasis is inevtaible and ishcemic injury beocme sirreversible.

Question 997

Concentric LV hypertrophy:

Answer 997

1. Uniform thickening of the ventricular wlal with the outer dimensions of the ventricle remaining almost unchanged, resulting in a narrowed ventricular cavity size.
2. Due to chronic elevation of ventricular pressures during systole, which is usually caused by long-standing HTN or aortic stenosis (increased LV afterload).

Question 998

A patient with PMH of lung cancer presents with unilateral right-sided face and arm swelling and engorgement of subcutaneous veins on the same side of the neck.

Answer 998

The brachiocephalic vein drains the ipsilateral jugular (drains face, neck) and subclavian veins (drain upper extremities). The bilateral brachiocephalic veins combine to form the SVC. Brachiocephalic vein obstruction causes symptoms similar to those seen in SVC syndrome, but only on one side of the body.

Question 999

Factors that prolong disease duration can increase disease prevalence even when the incidence is unchanged because diseased individuals live longer on average (eg, improved quality of care).

Question 1000

Class 1C > 1A > 1B

• 1C: Propafenone, flecainide
• 1A: Disopyramide, quinidine, and procainamide.
  
  • Affects phase 0 (Na⁺) and 3 (K⁺).
• 1B: Lidocaine
  
  • Useful for treating ischemia-induced ventricular arrhythmias

Question 1001

Health Maintenance Organization (HMO)

Answer 1001

Low monthly premiums, low copayments and deductibles, and low total cost for the patient:

• Confining patients to a limited panel of providers
• Requiring referrals from a PCP
• Denying payment for services that do not meet established evidence-based guidelines.

Question 1002

HIV-associated dementia:

Answer 1002

1. Subcortical dementia: attention/working memory problems, executive dysfunction, slow information processing.
2. Microglial nodules.

Question 1003

• Early personality and behavioral changes (eg, disinhibition, apathy, social inappropriateness, compulsive behaviors).
• Altered speecch (eg, paucity of speech, repeated phrases); brocas’s speech area.

Answer 1003

Pick bodies are round/oval, intracytoplasmic inclusions seen on silver stain in patients with frontotemporal dementia.

Question 1004

The cardiorespiratory response to exercise include?

Answer 1004

1. Increased HR, CO, RR in order to balance the increased total tissue oxygen consumption and CO₂ production.

• (UP) LV-EDV.
• (DOWN) LV-ESV: Heart to empty more completely.

2. These coordinated adaptions result in relatively constant arterial blood gas values whereas venous oxygen is decreased and venous CO₂ is increased.

Question 1005

The green discoloration of pus or sptuum seen during common bacterial infections is due to …?

Answer 1005

Presence of MPO, a blue-green heme-based enzyme that’s released from neutrophil azurophilic granules & forms bleach.

Question 1006

Cytarabine: a pyrimidine analogue antimetabolites

Fludarabine: a deamination-resistant purine nucleotide analogue that exerts its cytotoxicity by many mechanisms.

Question 1007

Which medication should be avoided/ use with caution in elderly patients?

Answer 1007

ANTICHOLINERGICS (eg, Diphenhydramine, TCA)

• Impaired memory, confusion, hallucinations, dry mouth, blurry vision, impaired sweating, tachycardia, and increased risk for falls.

Benzodiazepines

Antipsychotics

Antiarrhythmics

Centrally acting skeletal muscle realxants.

Question 1008

Root cause analysis:

Answer 1008

A quality improvement measure that identifies what, how, and why a preventable adverse outcome occurred. The first step involves collecting data mainly through interviewing multiple individuals involved in the steps leading to the outcome.

Question 1009

Use of concentrated oxygen therpay for neonatal respiratory distress syndrome may be complicated by retinopathy fo prematurity.

This abnormal retinal neovascularization is a major cuase of blindness in developed nations.

Question 1010

Long-term treatment of PD with levodopa can be complicated by period and sometimes unpredictable fluctuations in motor functions

Answer 1010

This “on-off” phenomenon is thought to be a consequence of progressive nigrostriatal neurodegeneration leading to a decreased therapeutic window for levodopa.

Question 1011

Crithyrotomy

Answer 1011

Passes through the superficial cervical fasciae, pretracheal fascia, and the cricothyroid membrane.

Question 1012

The great saphenous veins is a superifical vein of the leg that originates on the medial side of the foot, courses anterior to the medial malleolus, and then travels up the medial aspect of the leg and thigh.

It drains into the femoral vein within the region of the femoral triangle.

Question 1013

1. Used for hypertensive emergency:
   * Signs of end-organ damage, including ACS, encephalopathy, kidney injury, ICH, papilledema.
2. MOA:

• Dopamine-1 receptor agonist
• Resulting in vasodilation of arterial beds.
• Renal vasodilation and leads to increasd renal perfusion, diuresis, and natriuresis.
  
  • Espeically beneficial in patients with acute kidney injury.

Question 1014

1. Clinical symptoms:

• Fever, fatigue, weight loss
• Symmetric migratory arthritis
• Butterfly rash & photosensitivity
• Serositis: Pleurisy, pericarditis, & peritonitis
• Thromboembolic events.

2. Lab findings:

• Pancytopeniae.
• Hypocomplementemia (C3 & C4).
• Antibodies:
  
  • ANA (sensitive).
  • Anti-dsDNA & anti-Sm (specific)
• Renal involvement: Proteinuria & elevated creatinine (eg, DPGN).

Question 1015

Individuals who are aware of being participants of a study behave differently.

Question 1016

UMN due to a stroke, brain tumor cause:

• Spastic paralysis.
• Clasp-knife rigidity.
• Hyperreflexia.
• Upgoing plantar reflexes (Babinski sign).

Answer 1016

LMN:

• Eg) poliomyelitis and infantile spinal muscular atrophy.
• Flaccid paralysis.
• Hypotonia.
• Hyporeflexia.
• Muscle atrophy.
• Fasciculations.

Question 1017

• ↑ glycogen in muscle, but muscle cannot break it down –> Painful muscle cramps, myoglobinuria, arrhythmia.

Answer 1017

• Defected skeletal muscle glycogen phosphorylase.

Question 1018

• Stroke
• Intestinal or foot ischemiae
• Renal infarction (wedge-shaped)

Answer 1018

SYSTEMIC THROMBOEMBOLISM (from the left ventricle or atrium - a.fib).

Question 1019

Symptoms:

• Daytime somnolence.
• Non-restorative sleep with frequent awakenings.
• Morning headaches.
• Affective & cognitive symptoms.

PMH:

• Mild obesity (BMI ~ 30).
• Tonsilar hypertrophy.
• Hypothyroidism.

Answer 1019

• Relaxation of pharyngeal muscles leads to closure of airway.
• Loud snoring with periods of apnea.
• Sequelae: Systemic HTN.

Question 1020

Immunized mothers provide passive immunity via transplacental IgG, protecting infants against tetanus until they receive active immunization (vaccination) around age 2 months.

Question 1021

• Slows heart rate (negative chronotropic effect) with no effect on contractility (inotropy) and/or relaxation (lusitropy).
• Slows the rate of SA node firing by selective inhibition of funny sodium channels, thereby prolonging the slow depolarization phase (phase 4).

Question 1022

Methyltestosterone ADR?

Answer 1022

After conversion to DHT, androgens promote both follicular epidermal hyperproliferation and excessive sebum production.

Question 1023

Mast cell-stabilizing agents that inhibit mast cell degranulation independent of the triggering stimulus.

Question 1024

Due to compression of the lower trunk of the brachial plexus in the scalene triangle, the spaces bordered by the anterior and middle scalene muscle sand the first rib.

Question 1025

Ramelteon

Answer 1025

A melatonin agonist that is safe and effective in reducing time to sleep onset in the elderly.

Question 1026

Most common benign lung tumor?

Answer 1026

Hamartoma:

• Manifestations: asymptomatic.
• Excessive growth of a tissue typ enative to the organ of involvement.
  
  • The lung is the most common location.
    *

Question 1027

• Reddish skin discoloration without cyanosis.
• Tachypnea / tachycardia.
• Headache.
• N/V, confusion, weakness.
• Nitroprusside toxicity.

Answer 1027

Inhaled amyl nitrite oxidizes ferrous iron (Fe²⁺) present in hemoglobin to ferric iron (Fe³⁺), generating methemoglobin, which can bind cyanide.

• Inhibits cyt. C oxidase in the mitochondria, inhibiting oxidative phosphorylation, leading to lactic acidosis.

Sodium thiosulfate: Serves as sulfur donor to promote hepatic rhodanese-mediated conversion of cyanide to thiocyanate.

Question 1028

Hydrocephalus ex vacuo:

Answer 1028

Patients with neurodegenerative diseases (eg, AIDS dementia) can develop hydrocephalus ex-vacuo due to significant cortical atrophy, which allows the ventricles to expand while maintaining normal CSF pressure.

Question 1029

• Children aged 7-9 present with fever, cough, congestion, sore throat, and red eyes.
• P.E.: Bilateral conjunctival injection and an erythematous oropharynx.
• Their symptoms improve over 7 days with supportive care.

Answer 1029

• dsDNA transmitted via direct contact, fecal-oral route, or respiratory droplets.
• Outbreaks in crowded quarters (eg, day care centers, camp dormitories, military barracks).
• Pharyngoconjunctival fever.

Question 1030

PCSK 9 inhibitors

Answer 1030

Monoclonal antibodies that reduce LDL receptor degradation in the liver.

Question 1031

Lumbar spinal stenosis:

• Neurologic symptoms, including lower extremity pain, numbness/paresthesia, and weakness.
• Posture-dependent: lumbar flexion (eg, walking uphill, leaning on a stroller/shopping cart) relieves the pain.

Answer 1031

Formation of facet joint osteophytes and hypertrophy of the ligamentum flavum (a strong elastic ligament supporting the posterior aspect of the spinal canal).

Question 1032

Trichinella spiralis

Answer 1032

Encyst in striated muscle

• muscle inflammation (myalgia).

Question 1033

Heme oxygenase

Answer 1033

Converts heme to biliverdin, a pigment that causes the greenish color to develop in bruises several days after an injury.

Question 1034

Stages of lobar pneumoniae:

Answer 1034

1-2 days: Congestion

3-4 days: Red hepatization

5-7 days: Gray hepatization

• Uniformly gray
• Exudate full of WBCs, lysed RBCs, and fibrin.

Question 1035

A highly sensitive test should always be considered over a highly specific test when screening for life-threatening disease, where identification of a person with the disease is important.

Question 1036

Paranoid personality disorder

Answer 1036

• Pervasive pattern of distrust & suspiciousness beginning in early adulthood & occurring in a variety of settings.
• Believes being exploited & deceived by others.
• Interprets benign comments & events as threats; reacts angrily.
• Bears grudges.
• Questions loyalty of partner without justification.

Question 1037

Mechanisms of diabetic neuropathy?

Answer 1037

Endonueral arteriole hyalinization.

Question 1038

Deposition of rhomboid-shaped calcium pyrophosphate crystals within the joint space:

• Acute mono- or oligoarticular arthritis characterized by pain, joint swelling, erythema, and warmth.
• The knee joint is involved in >50% of pseudogout cases, whereas the first MTP joint is more frequently involved in gout.

Answer 1038

Question 1039

The appaeance of vacuoles and phospholipid-containing amorphous densities within mitochondria generally signifies irreversible injury, and implies a permanent inability to generate further ATP via oxidative phosphorylation.

Answer 1039

When the mitochondria are injured irreversibly, the cell cannot recover.

Question 1040

At the FRC, the tendencies of the chest wall to expand and the lung to collapse oppose one another, creating a negative intrapleural pressure of approximately -5 cm H₂O.

Answer 1040

PVR is at a minimum.

Question 1041

What are the two most important buffers in urine ?

Answer 1041

HPO₄^2- and NH_3.

Question 1042

• When a muscle exerts too much force, the GTOs inhibit contraction of the muscle, causing sudden muscle relaxation.
• The Ib sensory axons from the GTOs contact inhibitory interneurons in the spinal cord, which in turn synpases with the alpha-motor neurons that innervate the same muscle.

Question 1043

Skin tags that are benign and often peduncuated.

Question 1044

A polypeptide synthesized by the liver that acts as the central regulation of iron homeostasis.

Answer 1044

Hepcidin

Question 1045

The short gastric veins drain blood from the gastric fundus into the splenic vein.

Answer 1045

Pancreatic inflammation can cause a blood clot within the splenic vein, which can increase pressure in the short gastric veins and lead to gastric varices only in the fundus.

Question 1046

Cholestatic conditions such as primary biliary cirrhosis are potential cause of hypercholesterolemia leading to xanthelasma.

Question 1047

• ↓ Mineralocorticoids (↓BP, ↑K+, H+)
• ↓ Cortisol
• ↑ Renin, 17-hydroxy-progesterone.
• ↑ Sex hormones
  
  • XY: Presents in infancy as salt wasting or childhood (precocious pubery).
  • XX: Virilization in females.

Question 1048

11B-hydroxylase deficiency presents as?

Answer 1048

• ↑ 11-deoxycorticosterone ; ↑ BP
• XX: virilization.

Question 1049

• End-organ hypoperfusion in septic shock impairs tissue oxygenation and decreases oxidative phosphorylation, leading to a buildup of NADH and shuting of pyruvate to lactate following glycolysis.

Question 1050

• Affinity of the drug for its receptor.
• Amount of drug that is able to reach the target tissues.

Question 1051

1. The most common cause of hypothryodisim in indoine-sufficient regions such as the U.S.
2. Intense lymphocytic infiltrate, often with germinal centers.
   * Residual follicles are often surrounded by Hurthle cells (large oxyphilic cells filled with granular cytoplasm).
3. T₃ levels often remain normal until relatively late-stage hypothyroidism.

Question 1052

How to discuss sexual abuse?

Answer 1052

Acknowledging the sexual abuse and gently asking the patient if s/he would like to discuss it further is the most appropriate initial response.

Question 1053

Pneumococcal conjugate vaccines (PCV13) are strongly immunogenic in infancy due to both B and T cell recruitment.

Answer 1053

The N. meningitidis and H. influenzae vaccines are toher examples of capsular polysaccharide vaccines.

Question 1054

Gram (-) coccobacillus bordetella pertusis

• Pertussis toxin: Catalyzes ribosylation of Gαi/o leading to excessive adenylate cyclase activity.

Cultured on Bordet-Gengou medium.

Question 1055

DDx for necrotizing fasciitis

Answer 1055

• S. pyogenes
• S. aureus
• C. perfringenes

Question 1056

Knee Anatomy

Question 1057

Resistance is maximal in which airway segment?

Answer 1057

Medium-sized bronchi because of highly-turbulent airflow.

Question 1058

Used to detect DNA-binding proteins such as TFs, nucleases, and histones (eg, c-Jun).

Question 1059

• Infiltrative dermatopathy (pretibial myxedema).
• Exophthalmos.
• Periorbital edema.
• Eye movement limitations

Answer 1059

Autoimmune response directed against the TSH receptor.

Patients with Graves disease develop lymphocytic infiltration of the orbital and pretibial CTs due to increased TSH receptor expression in these regions.

Cytokines released by activated T cells increase fibroblast proliferation and secretion of GAGS, resulting in mucinous edema and tissue expansion.

Question 1060

Open-angle glaucoma:

• Progressive, painless, bilateral vision loss
• Optic disc cupping on funduscopy.

Answer 1060

Angle-closure glaucoma: painful monocular vision loss, headache, vomiting, and conjunctival injection.

Question 1061

The optimal sites for obtaining vascular access in the lower extremity during cardiac catheterization is the common femoral artery (continuation of external iliac artery) below the inguinal ligament.

Answer 1061

External iliac artery:

• Femoral artery
• Inferior epigastric artery.

Question 1062

Most of the venous drainage of the skin of the leg is via the great saphenous vein, the lymphatics of which drain into the superficial group of the inguinal lymph nodes.

Answer 1062

Lymph from the lateral aspect of the dorsum of the foot drains into lymphatics accompanying the small (lesser) saphenous vein, then drains into lymph nodes behind the knee in the politeal fossae.

Question 1063

While both ventilation and perfusion are increased at the base of the lung due to the effects of gravity, the perfusion increase is far greater, causing the V/Q ratio to decrease from the apex to the base.

Question 1064

The rubber-like properties of elastin are due to extensive cross-linking between elastin monomers, which is facilitated by lysyl oxidase.

Question 1065

• Hyponatremia (headache, weakness, altered mental status, seizures).
• Decreased plasma osmolality
• Maximally concentrated urine ( > 100 mOsm/kg).
• Lung mass.

Answer 1065

SIADH:

• Euvolemic hyponatremia with continued urinary Na⁺ excretion due to suppressed RAAS & production of natriuretic peptides.

Question 1066

Leydig cells

• Produce testosterone in response to stimulation by LH.
• Equivalent ot Theca cells in female

Answer 1066

Sertoli cells:

• Produce the hormone inhibin B in response to FSH form the anterior pituitary.
• Produce androgen-binding protein responsible for the high local testosterone concentration.
• Equivalent to granulosa cells in female.

Question 1067

A drop in PCO2 due to hyperventilation causes vasoconstriction –> reduction in cerebral blood volume –> decreased ICP.

Question 1068

When deoxygenated blood enters the alveolar capillaries of the lung, the increase in PO₂ increases the binding of oxygen to hemoglobin and causes the release of H+ and CO₂ from Hgb (Haldane effect).

Question 1069

1. Initiated by chronic hemodynamic stress & hyperlipidemia, which cause endothelial cell injury.

• Increased lipid permeability.
• Leukocyte (monocytes, T cells) and platelet recruitment.
• Migration & proliferation of VSMC from media to the intima.

2. VSMCs are stimulated to synthesize ECM (eg, collagen, elastin, proteoglycans) that form the fibrous cap typical of mature atheromas.

Question 1070

1. JONES criteria.
2. Biopsy:

• Aschoff body: Interstitial myocardial granuloma.
• Anitschkow cells: Macrophages with abundant cytoplasm and central, slender chromatin ribbons.

Question 1071

Viral bronchiolitis is a lower respiratory tract infeciton that usually occurs before age 2 and is most commonly caused by?

Answer 1071

RSV:

• Antecedent nasal congestion/dischage & cough
• Wheezing/crackles & respiratory distress
• Apnea in high-risk patients.

Question 1072

Caused by certain strains of Staphylococcus species that produce the exfoliatin exotoxin.

• Nikolsky’s sign: skin slipping off with gentle pressure.
• Epidermal necrolysis.
• Fever and pain associated with the skin rash.

Question 1073

Preventable medical errors involve harm to the patient by an act of commission or omission rather than from the underlying disease and are the result of failure to follow evidence-based best practice guidelines.

Question 1074

1. If a male is affected with the disease, he’ll pass his mutant X allele to all of his daughters, and therefore each female child will be heterozygous.
2. Sons of heterozygous mothers have a 50% chance of being affected.
3. Review pedigree (pg. 59)

Answer 1074

Ornithine Transcarbamylase deficiency

Fabry Disease

Wiskott-Aldrich Syndrome

Ocular albisnism

G6PD

Hunter

Bruton agammaglobulinemia

Hemophila A and B

Lesch-Nyhan Syndrome

Duchenne (& Muscular)

Question 1075

Right ventricle: 25/5 mm Hg.

Pulmonary artery: 25/10 mm Hg.

PCWP: 4-12 mm Hg.

Left Ventricle: 130/10 mm Hg.

Question 1076

Crohn disease with ileal resection or extensive ileal involvement can cause bile acid malabsorption, which may lead to impaired absorption of fat-solube vitamins (A,D,E,K).

Answer 1076

Vitamin K deficiency can result in impaired coagulation with easy bruising, large hematoma fomration in deep tissue and joints after minor trauma, and prolonged bleeding after surgery.

Question 1077

Incomplete CCW rotation (eg, 180 degrees) will result in midgut malrotation.

• Formation of fibrous bands (Ladd bands)
• Can lead to duodenal obstruction (bilious emesis during the first days of life) & volvulus (life-threatening bowel necrosis).

Question 1078

snRNPS are important components of the spliceosome, a molecule which removes intron from pre-mRNA during processing within the nucleus.

Question 1079

The anterior 2/3 of the posterior limb of the internal capsule is mainly composed of motor fibers (eg, corticospinal tract), and the posterior 1/3 contains sensory fibers (eg, thalamocortical tract).

Answer 1079

Most lesions result in pure motor or combined sensorimotor deficits.

Question 1080

Male unilateral hydronephrosis: ureteropelvic junction

Answer 1080

Bilateral hydronephrosis: posterior urethral valves.

Question 1081

Muscle important for crossing the legs:

• Abduction.
• Lateral rotation.
• Flexion @ knee.

Question 1082

Progressively weakening diaphragmatic contractions during maximal voluntary ventilation with intact phrenic nerve stimulation indicates NMJ pathology (eg, MG) and/or abnormally rapid diaphragm muscle fatigue (eg, restrictive lung or chest wall disease).

Question 1083

Alanine is the major amino acid repsonsible for transferring nitrogen to the liver for disposal. During the catabolsim of proteins, amino groups are transferred to a-ketoglutratate to form glutamate. Glutamate is then processed in the liver to form urea, the primary disposal form of nitrogen in humans.

Question 1084

Infants following consumption of HONEY

Answer 1084

1. The combination of nicotinic (eg, diploia, dysphagia) and muscarinic blockade (eg, dry mouth)

• Diplopia
• Dysphagia
• Dysphonia

2. Inhibits Ach release form presynaptic nerve terminals at the NMJ, thereby preventing muscular contractions: decrease in the compound muscle action potential (CMAP) following stimulation of a motor nerve.

Question 1085

Displacement of midshaft clavicular fractures is caused by the combined working of the sternocleidomastoid muscle pulling the medial fragment superiorly and posteriorly.

Answer 1085

In a distal clavicl fracture, contraction of the deltoid and the weight of the upper extremity act to pull the distal fragment inferolaterally.

Question 1086

Important in repair of spontaneous/toxic (base) deamination.

Glycosylase

Endonuclease

Lyase

Polymerase.

Ligase

Question 1087

A physician is ethically obligated to protect patient confidentiality and keep all personal health information private (including reproductive, sexual, substane use, and mental health concerns) unless patient has specifically provided verbal or written authorization for release of information to the family member.

Exceptions:

• Suspected child or elder abuse.
• Knife or gunshot wounds.
• Reportable communicable disease (eg, HIV).
• Threats to harm self or others.

Question 1088

The posteromedial papillary muscle is supplied solely by the PDA, a branch of the RCA (right dominant circulation) or LCX (left dominant circulation).

Question 1089

Left-sided heart disease can cause pulmonary HTN by increasing pulmonary venous pressure and congestion. This leads to a passive increase in pulmonary arterial pressure, which is made worse by reactive vasoconstriction and structural remodeling of the pulmonary vasculature secondary to impaired NO availability and increased endothelin expression.

Question 1090

As an antioxidant, SOD neutralizes ROS, preventing cell injury.

Question 1091

• Transient hypersensitivtiy disorder characterized by pruritic erythematous plaques that arise suddenly and resolve over hours.
• Most often caused by IgE-mediated degranulation of mast cells, leading to increased permeability of the microvasculature with edema of the superficial dermis.

Question 1092

Nitrates (via conversion to nitric oxide) activate guanylate cyclase and increase intracellular levels of cGMP. Increased levels of cGMP lead to myosin light-chain dephosphorylation, resulting in vascular smooth muscle relaxation.

Answer 1092

Arginine.

Question 1093

• Lethargy
• Enlarged fontanelle
• Protruding tongue
• Umbilical herniae
• Poor feeding
• Constipation
• Dry skin
• Jaundice

Question 1094

Isolated systolic HTN (systolic blood pressure >140 mm Hg with diastolic blood pressure <90 mm Hg) is due to age-related stiffness and decrease in compliance of the aorta and major peripheral arteries.

Question 1095

Statins are the most effective lipid-lowering drugs for primary and secondary prevention of cardiovascular events, regardless of baseline lipid levels.

Question 1096

(gcc) gccRccAUGG
* Among other factors, a purine (A or G) positioned 3 based upstream from AUG appears to play a key role in transcription initiation process.

Question 1097

• High-grade fever, headache, retro-orbital pain, bleeding (eg, epistaxis, petechiae/purpura).
• Diffuse macular rash.
• Muscle and joint pain.
• Leukopeniae/thrombocytopeniae.

Answer 1097

• Filoviruses
• ssRNA virus with 4 different serotypes.
• Transmitted by Aedges aegypti, which also causes chikungunya.

Question 1098

lateral ankle sprain is due to inverison of a plantar-flexed foot and most commonly involves the anterior talofibular ligament. Stronger forces can cause joint instablity inby injuring additional igaments.

Question 1099

D-xylose is a monosaccharide that’s absorbed directly without the action of pancreatic enzymes, and can be used to test for brush border absorptive function independent of pancreatic function.

Question 1100

Lead time bias.

Answer 1100

Occurs when a test detects or diagnoses the disease at an earlier stage than another test without impacting the natural history of the disease.

Question 1101

Exposure to risk modifiers sometimes occurs well before the exposures effect on the disease process is clinically evident.

In addition, sometimes exposures to risk modifiers must occur continuously over extended periods before disease outcome is affected.

Question 1102

Snuff box:

• Bounded medially by the tendon of the extensor pollicis longus and laterally by the tendons of the abductor polllicis longus & extensor pollicis brevis.

Risk for avascular necrosis and nonunion.

Question 1103

• Irregular, chaotic electrical activity within the atria and presents with absent P waves, irregularly irregular R-R intervals, and narrow QRS complexes.
• Associated with:
  
  • HTN.
  • CHF.
  • Hyperthyroidism.

Answer 1103

The AV node refractory period regulates the number of atrial impulses that reach the ventricle and determines the ventricular contraction rate in conditions where the atria undergo rapid depolarization.

Question 1104

• Encapsulated, lactose-fermenting, gram-negative bacillus tht appears mucoid in culture.
• Causes pneumoniae in subjects with impaired host defenses especially alcoholics.
• Production of thick, mucoid, blood-tinged sputum (eg, currant jelly sputum).

Question 1105

Focal.

• Originate from a localized region of one cerebral hemisphere (unilateral).
• Simple if consciousness is preserved or complex if there’s loss of consciousness.
  
  • Narrow-spectrum anticonvulsants: Carbamazepine, gabapentin, phenobarbital, phenytoin.

Answer 1105

Generalized.

• Involves both hemispheres at onset (bilateral).
• Eg) Juvenile myoclonic epilepsy.
  
  • Broad-spectrum anticonvulsants: Lamotrigine, Levitiracetam, Topiramate, Valproic acid.

Question 1106

• Persistent pattern of unstable relationships, mood labiility, and impulsivity.
• May exhibit suicidal dieation or behaviour in the context of an interpersonal crisis in which they feel rejected or abandoned.
• Splitting is a major defense mechanism.

Question 1107

• Pruritus & erythematous, weeping/crusted papules and plaques that occur in response to certain environmental antigens/ ingestion of certain foods (Eg, analgesic cream).
• Associated with other atopic diseases, such as allergic rhinits/ asthma.
• ↑IgE ***

Answer 1107

• Spongiosis found on skin biopsy.

Question 1108

What are the 2 most important factors for osteolastic differentiation?

Answer 1108

1. Macrophage colony-stimulating factor (M-CSF)
2. Receptor for Activated Nuclear Factor Kappa-B Ligand (RANK-L).
   * Osteoprotegerin competitively binds RANK-L & prevents its binding to RANK.

Question 1109

Somatic symptom disorder

• Excess anxiety & preoccupation with > 1 unexplained symptoms.
• Schedule regular visits with same provider.

Illness anxiety disorder

• Fear of having a serious illness despite few or no symptoms & consistently negative evaluations.

Conversion disorder

• Neuroglic symptoms incompatible with any known neurologic disease; often follows stress.

Answer 1109

Factitious disorder:

• Intentional falsification or inducement of symptoms with goal to assume sick role.

Malingering:

• Falsification or exaggeration of symptoms to obtain external incentives (secondary gain).

Question 1110

Acute ureteral obstruction increases hydrostatic pressure proximal to the constriction.

This pressure rise is transmitted back to the Bowman’s space, resulting in decreased GFR.

Question 1111

• Round cellular swelling.
• Displacement of the nucleus to the periphery.
• Dispersion of Nissl substance throughout cytoplasm.

Answer 1111

Chromatolysis Reaction of neuronal cell body to axonal injury.

Question 1112

• Chromaffin cells are modified postganglionic sympathetic neurons derived from the neural crest that receive sympathetic input
• They are stimulated by Ach released by sympathetic preganglionic neurons and secrete catecholamines directly into the blood stream to amplify sympathetic nervous system activity.

Question 1113

Invasive vascular procedures can be complicated by atheroembolic renal disease.

Answer 1113

Light microsocpy shows a partially or completely obstructed arterial lumen with needle-shaped cholesterol clefts within the atheromatous thrombus.

Question 1114

Catabolism of several essential amino acids (valine, isoleucine, methionine, and threonine) along with odd-chain fatty acids results in the generation of propionyl-CoA.

Answer 1114

Propionyl-CoA is subsequently converted to methylmalonyl-CoA in a reaction catalyzed by biotin-dependent propionyl-CoA carboxylase.

Question 1115

• UAA.
• UAG.
• UGA.

Question 1116

AV shunts increase cardiac preload by increasing the heart rate and volume of blood flow back to the heart. This is reflected on the ventricular pressure-volume loop by elongation of the diastolic filling segment and a higher EDV.

Answer 1116

Because AV shunts allow blood to bypass the arterioles, TPR is reduced, thus decreasing the afterload as well.

Question 1117

1g carb/protein = 4 kcal

1g alcohol = 7 kcal

1g fatty acid = 9 kcal

Question 1118

Treatment for Streptococcus agalactiae (group B streptococci)?

Answer 1118

Intrapartum penicillin prophylaxis.

Question 1119

1. Volume per given pressure.
2. Decreased compliance is the hallmark of pulmonary fibrosis.

Question 1120

Horizontal transection of the rectus abdominis muscle must be performed with great caution as the inferior epigastric arteries enter this muscle at the the level of the arcuate line.

Question 1121

Primary tuberculsois:

• Inhalation of aerosolized M. tuberculosis.
• Formation of Ghon foci in the lower lungs.
  
  • Ghon complex: Ghon foci + hilar adenopathy.
• Caseating granuloma (walled off by Th₁-lymphocytes activated macrophages).

Answer 1121

Secondary tuberculosis:

• Most often in immunosuppressed patients
• Apical cavitary lesions (increased O₂₎, causing caseous and liquefative necrosis.

Question 1122

• Weakness
• Hypotonia
• Hypoketotic hypoglycemiae.

Answer 1122

Impairs fatty acid transport from the cytoplasm into mitochondria, preventing β-oxidation of fatty acids into acetyl-CoA.

Question 1123

Suspensory ligament of the ovary:

• Contains the ovarian artery (major ovarian blood supply arising from the abdominal aorta entering the ovary at the hilum), vein, lymphatics, and nerve.
• Must be ligated to prevent heavy ovarian bleeding in an oophorectomy.
• Ureter is in close proximity ***

Question 1124

• Loss of taste from the posterior 1/3 of the tongue: CN IX
• Loss of gag reflex: CN IX, X
• Dysphagia: CN IX, X
• Dysphonia/hoarseness; CN X
• Soft palate drop with deviation of the uvual toward the normal: CN X
• SCM and trapezius muscle paresis: CN XI.

Question 1125

Anxiety (>4 weeks in children, >6 months in adults) due to separation from attachment figures.

Question 1126

African American women have greater bone density and lower risk of fractures than women of any other ethnicities.

Question 1127

Exteranl iliac artery supplies the inferior epigastric artery and the deep circumflex iliac artery before becomign the femoral artery

Question 1128

Which mitochondrial enzyme is necessary for ketogenesis?

Answer 1128

HMG CoA Lyase

Question 1129

Highly soluble gas (high blood/gas partition coefficient)

• Blood saturates slowly, leading to a delayed rise in partial pressure —> decreased pressure slows brain saturation, increasing onset time.

Question 1130

• A lipopeptide antibiotic with activity against gram-positive organisms, including MRSA.
• Disrupts the bacterial membrane by creating transemembrane channels that cause intracellular ion lekage.
• Inactivated by pulmonary surfactant, so it’s ineffective in the treatment of pneumoniae.
• Increased creatine phosphokinse levels and myopathy.

Question 1131

Presbyopia

• Progressive denaturation of lens proteins and changes in lens curvature cause the lens to become less elastic and lose its accomodating power.
• This causes the image of near objects to focus behind the retina
• Can compensate for myopia, which conversely focuses the image in front of the retina.
• AGE-RELATED CHANGES.

Question 1132

Femoral head ostenecrosis:

• Vasculitis.
• Corticosteroid therapy.
• SCD.
• Alcoholism.
• Legg-Calve-Perthes Disease.

Answer 1132

Medial circumflex artery

Question 1133

A 34-yeard-old man is brought ot the ER with new-onset confusion/leatharrgy, abdominal pain, and tachypnea. Lab studies reveal increased anion-gap metabolic acidosis. Tx?

Answer 1133

Insulin & Normal saline.

• Decreased ketogenesis –> Increase in serum bicarbonate.
• Insulin causes an intracellular shift of potassium, resulting in a decrease in the serum potassium level.
• Rehydration with normal saline to normalize serium sodium concentration and decrease serum osmolality.

Question 1134

Prader-Willi Syndrome

• Imprinting disorder caused by a paternal deletion of part of chromosome 15.
• Infancy: Hypotonia & hyperphagia leading to gross motor delays and obesity, respecitvely.

Answer 1134

Angelman syndrome:

• Maternally-inherited deletion of the same portion of chromosome 15 while the paternal allelle isn’t expressed.
  *

Question 1135

Gastric ulcers arise along the antrum of lesser curvature:

• Penetrate left gastric artery, leading to hemorrhage (–> hematemesis)

Answer 1135

Ulcers in the posterior duodenal bulb can erode into the gastroduodenal artery and cause bleeding.

Question 1136

Right lower quadrant tenderness with rebound as well as a palpable mass. CT scan of the abdomen and pelvis demonstrates a periappendiceal fluid collection (/abscess). Culture of the fluid would most likley isolate which of the following organisms?

Answer 1136

Perforated appendicitis that has evolved into an intra-abdominal abscess.

B. fragilis is a common anaerobic gram-negative bacillus that’s frequently isolated (can also be aspirated).

Question 1137

A 45-year-old woman with a several-year history of SLE being treated with multiple medications is found dead at home. Her clinical recrods showed progressive truncal obesity, faical plethora, and proximal muscle weakness. Lab studies showed mild hyperglycemia. At autopsy, she’s found to have a left coronary artery mainstem thrombus that caused sudden cardiac death. Dx?

Answer 1137

Iatrogenic Cushing Syndrome due to prolonged administration of glucocorticoids for management of her SLE.

• Causes bilateral atrophy of the adrenal cortices.
• Sudden cessation of glucocorticoids after prolonged use can precipitate adrenocortical insufficiency and adrenal crisis.

Question 1138

High levels of dietary aflatoxin exposure (esp. in Asia and Africa) is associated with a G:C –> T:A transversion in codon 249 of the p53 gene, a mutation thought to greatly increase the risk of developing hepatocellular carcinoma.

Question 1139

The subsequent shock with hyponatremia, hyperkalemia, and hypoglycemia(due to cortisol deficiency) heralds the onset of adrenal crisis resulting from bilateral hemorrhagic infarction of the adrenal glands.

Question 1140

The most important mechanisms of the development of diabetic neuropathy are:

Answer 1140

• Non-enzymatic glcosylation of proteins leads to increased thickness, hyalinzation, and narrowing of the walls of the arteries.
• These changes lead to diabetic microangiopathy of endoneural arteries.

Question 1141

Lung adenocarcinoma:

• Glandualr differentation.

BAC (eg, adenocarcinoma in-situ/lepidic predominant adenocarcinoma of the lungs)

• Tall, columnar cells that spread along the alveolar septae and may form papillary projections into the alveolar spaces.

Question 1142

• Proximal muscle weakness
• Cranial nerve involvement, particularly oculobulbar
• Autonomic symptoms, such as dry mouth or impotence.

Answer 1142

LEMS.

Question 1143

• Usually no symptoms of sickle cell anemiae
  
  • Normal Hgb, reticulocyte count, RBC indicies & morphology
• Relative protection against P. falciparum.
• Hemoglobin electrophoresis shows both Hb A & Hb S, with the amount of Hb A greater than Hb S.

Question 1144

RT-PCR

• Used to detect and quantify levels of mRNA in a sample.

Question 1145

Profound cerebral hypoperfusion may lead to global cerebral ischemia.

Answer 1145

Watershed infarction: bilateral wedge-shaped strips of necrosis over the cerebral convexity, parallel and adjacent to the longitudinal cerebral fissure.

The pyramidal cells of the hippocampus & Purkinje cells of the cerebellum are the most vulnerable.

Question 1146

Clapse-knife spasticity:

• Initial resistance to passive extension followed by a sudden release of resistance.
• Internal capsule affected (UMN).

Question 1147

Serotypes L1 through L3 cause LGV, a sexually transmitted disease characterized initially by painless ulcers with later progression to painful inguinal lymphadenopathy and ulceration. Chlamydial inclusion bodies are seen in host cell cytoplasm.

Answer 1147

Nongonococcal urethritis and epididymitis in men.

• Light microscopy of a Gram stain speicmen shows numerous neutrophils but no organisms.
• Tx: Azithromycin.

Question 1148

Platelet-derived growth factor (PDGF) released by locally adherent platelets, dysfunctional endothelial cells, and infiltrating macrophages promotes migration of smooth muscle cells (SMCs) from the media into the intima and increases SMC proliferation.

Platelets also release TGF-B, which is chemotactic for SMCs and induces intestitial collagen production.

Question 1149

Iron absorption primarily occurs?

Answer 1149

Duodenum & Proximal jejunum

Question 1150

Albinism:

• Tyrosinase deficiency.

Answer 1150

Vitiligo:

• Autoimmune destruction of melanocytes.

Question 1151

• Decreased ventricular compliance.
  
  • Elevated LV filling pressures.
• Normal LV EDV
• Normal LV EF

Answer 1151

Diastolic heart failure:

• HTN (hypertrophic cardiomyopathy).
• Obesity
• Infiltrative disorders (eg, transthyretin-related amyloidosis, sarcoidosis, hemochromatosis)

Question 1152

• Peripheral precocious puberty (eg, early menarche).
• Irregular cafe-au-lait macules.
• Polyostotic fibrous dysplasia (osteolytic-appearing lesions of the hip & Pelvis)
• Endocrine abnormalities (eg, thyroid disorders).

Answer 1152

McCune albright hereditary disorder

Question 1153

The Fas receptor acts to initiate the extrinsic pathway of apoptosis.

Mutations involving the Fas receptor or Fas ligand can prevent apoptosis of autoreactive lymphocytes, thereby increasing the risk of autoimmune disorders such as SLE.

Question 1154

Patients with deficiencies in lysosomal enzymes cannot break down GAGs, resulting in mucopolysaccharidoses (eg, Hurler syndrome, Hunter syndrome) characterized by soft tissue and skeletal disease.

Question 1155

• Swollen, red, and painful joint.
• Synovial fluid purulent (WBC > 50,000mm³).

Answer 1155

• Gonococcal arthritis:
  
  • STI that presents as either purulent arthritis (eg, knee) or traid of polyarthralgia, tenosynovitis, dermatitis.
• Best evaluated with diagnostic arthrocentesis and synovial fluid analysis.

Question 1156

• Renal biopsy: Widespread narrowing of the renal arterioles with deposition of homogeneosus, glassy material in the subendothelial space that stains with periodic acid-Schiff (PAS) stain.

Answer 1156

• Hyaline arteriosclerosis, typically secondary to poorly controlled HTN or DM.

Question 1157

Malignant HTN causes fibrinoid necrosis and hyperplastic arterioslcerosis.

Answer 1157

• Diastolic pressures > 120-130 mm Hg
• Onion-like concentric thickening of the walls of arterioles as a result of laminated smooth muscle cells (SMC) and reduplicated basement membranes.

Question 1158

• Persistent &/or prolonged pain.
• Worse with movement or change in position.
• Often follows repetitive activity.
• Pain is typically reproduced with palpation.

Answer 1158

Uncomplicated musculoskeletal derangements:

• Tx: NSAIDs, moderate exercise.

Question 1159

Pathophysiology of Zenker diverticulum:

Answer 1159

Cricopharyngeal motor dysfunction.

Question 1160

A midline episiotomy is a vertical incision from the posterior vaginal opening to the perineal body.

Answer 1160

• Bulbospongiosus muscle
• External anal sphincter muscle
• Superficial & deep transverse perineal muscles.
• Fibers from the external urethral sphincter, levator ani, and muscular coat of the rectum.

Question 1161

Acutely intoxicated patients (eg, patients who are temporarily incapacitated) should not be allowed to make important health care decisions & should be reassessed when sober.

Question 1162

Hematogenous osteomyelitis is most common in children and usually affects the metaphysis of long bones due to the slower blood flow and capillary fenestrae in this region.

Question 1163

Confident interval of mean =

mean +/- [z-score for confidence level] X [SE]

Question 1164

Primary spontaneous pneumothorax

• apical supleural blebs

Answer 1164

Tension Pneumothorax:

• Cause the tracheal deviation away from the affected lung because the excess air pushes against the mediastinal structures.

Question 1165

Tx for anaphylactic shock?

Answer 1165

Epinephrine:

• Stimulation of a1 receptors counteracts the vasodilatation of cutaneous and viscera vasculature, thus increasing blood pressure
• B1 effect and cardaic output also increase blood pressure and improve peripheral perfusion
• B2 receptors results in bronchodilatation, making it also a popular choice for the treatment of severe asthmatic reactions.

Question 1166

• Affects liver (hepatomegaly, RUQ)
• Encapsulated & calcified cyst containing fluid and budding cells that’ll eventually become daughter cysts: “eggshell calcification”
• Cystic manipulation: anaphylactic shock.

Answer 1166

E. granulosus

Question 1167

Likelihood >1: test result is associated with the presence of the disease;

Answer 1167

Likelihood <1: test result is associated with the absence of disease.

Question 1168

A communicating hydrocele results when the processus vaginalis remains patent and allows peritoneal fluid to accumulate in the tunica vagianlis.

Question 1169

• Cannabinoid that produces euphoria and perceptual distortions.
• Increased appetite.
• Red eyes (conjunctival injection).
• Slowed reflexes
• Dizzines
• Impaired coordination.

Question 1170

Often associated with prolonged hypoxia:

• Large-cell lung cancer
• Tuberculosis
• CF
• Suppurative lung diseases: empyema, bronchiectasis, and chronic lung abscesses.

Question 1171

CCl_4: free radical injury

Question 1172

• Bear no resemblance to the tissue of origin
• Composed of pleomorphic cells with large, hyperchromatic nuclei that grow in a disorganized fashion.
• May also contain numerous, abnormal mitoses and giant tumor cells.

Question 1173

Presence of 2 or more cell line, each with a unique nuclear genome, within the same individual.

Answer 1173

• Somatic: Affects the cells forming the body, causing disease manifestations to develop in affected individuals (eg, Turner syndrome).
• Germline: Affects the cells that give rise to gametes, allowing the affected genes to pass to the offspring.

Question 1174

Respiratory changes seen in the elderly

Answer 1174

• ↑ Lung compliance (loss of elastic recoil).
  
  • ↑ RV
  • ↓ FEV_{1 &} FVC.
• Normal TLC.

Question 1175

Synaptophysin is a transmembrane glycoprotein found in the presynpatic vesicles of neurons, neuroectodermal and neuroendocrine cells.

Answer 1175

Astrocytes, oligodendrocytes, and ependymal cells stain positively for GFAP.

Question 1176

The CN VI nucleus projects to the ipsilateral lateral rectus muscle (abducts the eye) and contralateral medial rectus subnucleus of CN III (adducts the eye) via the MLF.

• Lesions to the dorsal pons can disrupt MLF.

Question 1177

• LV must now accommodate the regurgitant blood volume along with normal pulmonary venous return, there’s increased LVEDV.
• The incompetent mitral valve forms a low-resistance regurgitant pathway for blood to flow into the LA, decreasing LV afterload.
• Much of the total stroke volume is lost to regurgitation into the LA, resulting in decreased forward stroke volume and reduced cardiac output.

Question 1178

• Increased appetite/hypersomnia
• Intense psychomotor retardation
• Severe depression
• Sleep disturbance/vivid nightmares.
• “CRASH”

Answer 1178

Stimulants (eg, cocaine) withdrawal.

Question 1179

Regardless of the patient’s hydration status, the majority of water reabsorption in the nephron occurs in the proximal tubule passive with the reabsorption of solutes.

Answer 1179

In the dehydrated state, ADH acts on the kidney to improve the water permeability of the collecting ducts, allowing production of maximally concentrated urine (osmolarity fo 1200 mOsm/L).

Question 1180

Vaccation againist H. influenza is with the protein-conjugated Hib vaccine, which confers immunity only to the more invasive type B strain:

• Bacteremia
• Pneumoniae
• Epiglottitis
• Meningitis

Answer 1180

Nontypeable H. influenza cause acute otitis media, sinusitis, and bronchitis.

Question 1181

• Progressively worsening dizziness.
• Limb and truncal ataxia.
• Dysarthria
• Visual disturbances (eg, diplopia)
• Extensive cerebellar Purkinje cell degeneration, following small cell lung cancer.

Answer 1181

Anti-Yo, Anti-P/Q, anti-Hu.

Question 1182

Varenicline: a partial neuronal nicotinic receptor agonist and prevents nicotine stimulation of the mesolimbic dopamine system associated with nicotine addiction.

Answer 1182

• Reduces nicotine cravings while decreasing the pleasurable effects of cigarettes and other tobacco products.

Question 1183

Therapeutic ionizing radiation (eg, gamma rays, x-rays)

Answer 1183

• dsDNA breakage.
• Free radical formation.

Question 1184

• ß₂ receptors (+M3 muscarinic receptor) promotes insulin secretion
• α₂ receptors inhibits insulin release.

Answer 1184

α_2-mediated inhibitory effect is predominant, causing sympathetic stimulation to lead to overall inhibition of insulin secretion.

Question 1185

A chest tube for drainage of plueral effusion is placed through the skin and subcutaenous fat into the 4th or 5th intercostal space in the anterior axillary or midaxillary line.

The tube traverses through the serratus anterior muscle, intercostal muscles, and parietal pleura.

Question 1186

The human multidrug resistance (MDR1) gene codes for P-glycoprotein, a transmembrane ATP-dependent efflux pump protein that has a broad specificty for hydrophobic compounds.

Question 1187

• Bilaterally enlarged, cystic fetal kidneys and oligohydramnios
• Less severe phenotypes more often present with hepatic complications (eg, hepatomegaly ,portal HTN) and HTN during childhood or early adulthood.

Answer 1187

Potter sequence ***

Question 1188

Of following, which is better tolerated by elderly?

A. Chlorpheniramine.

B. Diphenhydramine.

C. Hydroxyzine.

D. Lotaradine (2nd-gen antihistamines).

E. Promethazine.

Question 1189

alpha-1 adrenergic agonists (eg, phenylephrine)

• Increased vascular smooth muscle contraction.
• Pupillary dilator muscle contraction (mydriasis)
• Intestinal and bladder sphincter muscle contraction.

Answer 1189

β₁ agonist: Gs

• Heart rate (chronotropy)
• Contractility (inotropy) & conduction

β₂ agonists:

• Vasodilation
• Bronchodilation
• Increased insulin release
• Decreased uterine tone (tocolysis).
  
  • Eg) terbutaline,

Question 1190

Rapid surge/leakage of intracellular proteins (eg, CK) following a reperfusion injury is best explained by?

Answer 1190

CELL MEMBRANE DAMAGE.

Question 1191

Cases (subjects with the disease of interest) vs. Controls (subjects without the disease of interest).

• Selected regardless of exposure status.
• Controls and cases are matched base on independnet variables (eg, age, sex) to decrease the effects of confounding.

Question 1192

• Urine protein excretion > 4.5 g
• Glomerulalr capillary wall thickening without an increase in cellularity.
• “Spike and dome” appearance of subepithelial deposits.

Answer 1192

Membranous nephropathy.

• IgG4 antibodies to PLA2R.
• Secondary to underlying solid tumors (eg, lung and colon carcinoma)
• Chronic infection.
• Autoimmune disease.

Question 1193

PRPP-synthetase mutation

Answer 1193

• Increased production of purines due to feed-forward activation of the purine synthesis pathway.
• Hyperuricemia and an increased risk of gout.

Question 1194

Congential long QT syndrome ***

Answer 1194

Decreased outward potassium flow and resultant prolongation of the A.P.

Ventricualr tachycardia and sudden death.

Question 1195

• Hyperinflated lungs.
• Airway mucous plugging.
• Cellular infiltration of the bronchial wall.

Answer 1195

Bronchial asthma:

• Long term use of fluticasone & budesonide.
  
  • Pronounced anti-inflammatory effects.

Question 1196

• Major depressive disorder
• Accompanied by psychotic symptoms (delusions of causing evil, auditory hallucinations)

Answer 1196

Major depressive disorder with psychotic features.

• Psychotic symptoms are present only during the episodes of major depression.

Question 1197

• IgA deficiency
• X-linked agammaglobulinemia
• Common variable immune deficiency

Answer 1197

Giardiasis

Question 1198

Which most likely accounts for the color of the patient’s sputum?

Answer 1198

MPO:

• Catalyzes the production of hypochlorous acid from chloride and hydrogen peroxide during the phagocytic respiratory burst.

Question 1199

• Argues with adults, defies authority figures, refuses to follow rules.
• Deliberately annoys others.
• Blames others for own mistakes or misbehaviour.
• Easily annoyed, angered, resentful, or vindictive.

Question 1200

Injury to the radial nerve during its passage through the supinator canal may occur due to repetitive pronation/supination of the forearm, direct traum, or subluxation of the radius.

• Weakness during finger/thumb extension (“finger drop”)
• NO sensory deficts over posterior aspects.
• Preserved triceps reflexes.

Question 1201

Patients with medically intractable symptoms of Parkinson disease may benefit from high-frequency deep brain stimulation of ?

Answer 1201

Gpi/STN as it promotes thalamo-cortical disinhbition with improved mobility.

Question 1202

IHC analysis indicates that the malignant cells have decreased integrin expression. These cells are most likley to exhibit poor adhesion to ?

Answer 1202

Fibronectin:

• Binds to integrins, matrix collagen, and GAGs, serving as a mediator of cell adhesion and migration.

Question 1203

An arrangement in which a payor pays a fixed, predetermined fee to cover all the medical services required by a patient

Answer 1203

Capitation.

Question 1204

Although sympathetic discharge during exercise causes increased cardiac output and splanchnic vasoconstrcion, there’s only a modest increase in mean arterial pressure due to vasodilation within active skeletal muscles.

Question 1205

The lesion most often underlyings table angina ifs a fixed atheromatous obstruction of coronary artery occluding at least 75% of the luminal cross sectional area.

Question 1206

• Preoccupation with >1 perceived physical defects.
• Repetitive behaviour or mental acts performed in response to the preoccupation.
• Significant distress or impairment.
• Specific insight (good, poor, basent/delusional beliefs).

Question 1207

• GI hemorrhage with hematemesis
• Guaiac-positive stools
• Ecchymoses
• Rodenticides ingestion.

Answer 1207

Warfarin toxicity —> Infuse FFP.

Question 1208

• Preoccupation with order, perfectionism, and control
• Ego-syntonic; behavior consistent with one’s own beliefs and attitudes
• DOES NOT INVOLVE COMPULSIONS PERFORMED IN RESPONSE (VS. OCD).

Question 1209

Insulin deficiency is causing increased production of gluconeogenic precursor (glycerol) that are subsequently converted to glucose in the liver by ?

Answer 1209

Glycerol Kinase.

Question 1210

• Microcytic anemiae (MCV < 75uM³)
• Increased Hemoglboin A2 (a2δ2)
• Target cells

Answer 1210

• Variety of DNA mutations affecting the transcription, processing, and translation of beta-globin mRNA.

Question 1211

• Cytokeratin/ keratin: Intermediate filaments present in epithelial cells
• Vimentin: intermediate filament present in mesenchymal tissue.

Question 1212

• Maintain neutral, open, and nonjudgmental stances
• Questions should be direct & specific.
• Inquire about all sexual partners (men, women, or both).

Question 1213

• Irritation of the highly vascular mucosa at the anterior nasal septum, which contains Kiesselbach plexus.

Answer 1213

• Superior meatus: sphenoidal * posterior ethmoidal isnuses
• Middle meatus: frontal, maxillary, and anterior ethmoidal sinuses; most common site of nasal polyps.
• Inferior meatus: nasolacrimal ducts

Question 1214

• Skin & Mucosal telangiectasias.
• Recurrent severe nosebleeds.

Question 1215

• Hypersensitivity vasculitis:
  
  • Pathogen exposure
  • Penicillins, cephalosporins, sulfonamides, phenytoin, allpurinol
• Markedly inflamed small blood vessels with fibrinoid necrosis
• Non-blanching palpable purpura in the lower extremities..

Question 1216

• Intestinal lipase inhibitor.
  *

Question 1217

Severe hypoplasia of marrow erythroid elements in the setting of normal granulopoiesis and thrombopoiesis

Answer 1217

Pure red cell aplasia:

• Associated with thymoma, lymphocytic leukemias, Parvovirus B19.

Question 1218

What hemodynamic changes are seen in anemiae?

Answer 1218

• Decreased O₂ content (Decreased Hb concentration).

Question 1219

Ranolazine: an antianginal agent and exerts it effect by inhibiting the late phase of inward sodium channels in ischemic cardiac myocytes.

Question 1220

What’s by far the most effective preventive intervention in almost all patients?

Answer 1220

SMOKING CESSATION.

Question 1221

• Produced by plotting sensitivity against (1-specificity).
• Accuracy: generally reflected by the area under the ROC curve.

Question 1222

Transcription initiation box

Answer 1222

TATA

CAAT

Question 1223

Cells cover the surface of the dish and are piled up into the mounds.

Answer 1223

Malignant cells: cover the medium with a single layer of cells and then continue to divide, eventually piling up into mounds.

Question 1224

The stellate cells (Ito cells) can differentiate into a myofibroblast upon injury to the liver and plays a large role in the production of fibrosis in cirrhosis.

Answer 1224

The regenerative nodules seen in liver cirrhosis are composed of proliferating hepatocytes.

Question 1225

Cardiogenic shock (eg, MI HF, valvular dysfunction, arrhythmia).

Answer 1225

• ↓ PCWP (right ventricular infarction).
• ↓ CO
• ↑ SVR

Question 1226

What hemodynamics are found in P.E. (eg, obstrucitve shock)?

Answer 1226

• ↑ Central venous pressure (JVP).
• ↓ CO
• ↑ SVR

Question 1227

When renal perfusion pressure decreases, RPF falls to a greater extend than GFR due to GFR autoregulation.

As a result, the filtration fraction increases with decreasing renal perfusion pressure.

Question 1228

Tx for xerosis (asteatotic dermatitis, eg winter itch) ?

Answer 1228

Moisturizers.

Question 1229

Blocks organic anion transporters on renal tubular cells:

• Inhibit tubular secretion of certain antibiotics
• Increased uric acid excretion.

Question 1230

• Increased intrathoracic pressure during a coughing episode decreases venous return to the heart thereby transeintly decreasing cardiac output and cerebral perfusion.

Question 1231

In an agglutination inhibition test, the presence of agglutination is considered a negative result.

Question 1232

• A person receives 2 copies of a given chromosome from 1 parent and no copies from the other.
• Can cause Prader-Willi syndrome (maternal disomy) and Angleman syndrome (paternal disomy).

Question 1233

During transduction process, bacterial DNA fragments are packed into structurally normal virions in place of phage DNA. Consequences?

Answer 1233

Can inject DNA into bacteria.

CANNOT produce progeny.

Question 1234

Dopamine: D1 > B1> a1

Question 1235

• Ergot alkaloid commonly used to treat acute migrane headache.
• Induces vasospastic angina as it constricts vascular smooth muslce via stimulation of both alpha-adrenergic and serotonergic receptors.

Question 1236

• Common inflammatory condition characterized by accumulation of scaly, greasy skin on the scalp, face, ears, eyelids, and eyebrows.
• Seen in HIV & Parkinson Disease.

Question 1237

Prosencephalon

• Telencephalon.
• Diencephalon.

Mesencephalon

Rhombencephalon

• Metencephalon: Pons, cerebellum, upper 4th ventricles
• Myelencephalon: Medulla & lower 4th ventricle.

Question 1238

• Pinpoint pupils.
• Loss of horizontal gaze.
• Quadriparesis.
• Decerebrate posturing (extended upper & lower extremities).
• Rapidly evolving coma (reticular activating system disruption).

Question 1239

• Ursodeoxycholic acid
• Reduces cholesterol secretion and increases biliary bile acid concentration.
  *

Question 1240

(Total filtration rate) - (total tubular reabsorption rate)

• (GFR X Plasma concentration) - (total tubular reabsorption rate).

Question 1241

Known pharmacologic properites of the drugs:

• Gastritis associated with NSAID use
• Nephrotoxicity due to aminoglycosides.

Question 1242

• Vertebral (T10) compression fractures
• Caucasian ethnicity
• Female Sex
• Advanced age
• Positive smoking history
• Glucocorticoid use.

Answer 1242

Normal Lab values.

Question 1243

• Bluish color (polychromasia) on Weight-Giemsa stain of reticulocytes represents residual ribosomal RNA.

Question 1244

Presence of left ventricular systolic dysfunction due to reduced coronary blood flow at rest that is partially or completely reversible by coronary revascularization.