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USMLE Wrong Answer Facts > UWorld QBank - 2nd Round - part 2 > Flashcards

UWorld QBank - 2nd Round - part 2 Flashcards

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USMLE® Step 1 flashcards
1
Q

What molecular process can lead to genetic imprinting?

A

DNA methylation -> silence gene

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2
Q

What does pure motor weakness of arm/leg and contralateral lower face, and clasp-knife spasticity indicate?

A

Clasp knife -> UMN lesion
Weakness -> infarct of motor tracts of opposite side
-INTERNAL CAPSULE INFARCT

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3
Q

What feature of Grave’s disease will not improve with beta-blocker treatment and why?

A

Exophthalmos - because this is caused by increased soft tissue mass in the bony orbit due to enlargement of ocular muscles (myositis), fibroblast proliferation, and overproduction of ground substance in response to antithyroid Abs

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4
Q

What would result from a deficiency in carnitine?

A

Decreased ability for fatty to enter mitochondria for beta-oxidation -> decrease acetyl CoA -> decreased acetoacetate

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5
Q

What is another name for lactose? What does this molecule get converted to in the body?

A

Galactosyl-beta-1,4 -glucose -> converted to galactose by beta-galactosidase

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6
Q

Which dimorphic fungus forms single broad-based buds and multicellular structures with branching tubular cells? Which areas is it endemic in?

A

Blastomyces dermatitidis - Ohio/Mississippi river valleys, great lakes

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7
Q

What is Tardive dyskinesia? When is it most likely to occur, and from which substance?

A
  • Involuntary perioral movements (biting, chewing, grimacing, and tongue protrusions)
  • Possible choreathoid movements of head, limbs and trunk
  • 4 months-4years treatment (mbe irreversible)
  • Risperidone (atypical AP)
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8
Q

What is acute dystonia and when is it most likely to occur? How can you treat?

A

Muscle spasms, sustained upward eleveation of eyes
-4 hours - 4 days of AP tx
Tx: antihistamines (diphenhydramine) or anticholinergics (benztropine & trihexyphenidyl)

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9
Q

What are the 3 specific actions of vWF?

A

Released by Weibel-Palade bodies in endothelium:

  1. Binds exposed subendothelial collagen, facilitating cross-linking with platelet glycoproteins (Gp1b)
  2. Facilitates platelet aggregation, under high shear stress situations
  3. Protective protein carrier for factor VIII
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10
Q

What would result from impaired formation of N-acetylglutamate?

A

N-ag activates Carbamoyl phosphate synthetase I to make Carbamoyl phosphate from CO2 NH4+ and 2 ATP

Deficiency of n-ag would result in increased ammonia and decreased urea production

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11
Q

What problem occurs with Vit. Deficiency?

A

Marked decrease in absorption of both calcium and phosphorous -> PTH will increase (PTH also increases urinary phosphorous excretion)

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12
Q

What is the main deficiency in dilated cardiomyopathy?

A

Decreased ventricular contractile force

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13
Q

Which situations lead to diastolic cardiac dysfunction?

A

Diastolic dysfxn most often from hypertensive heart disease -> concentric ventricular hypertrophy -> poor ventricular wall compliance

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14
Q

A patient with pulmonary mass complains of shoulder pain, persistant hiccups and dyspnea, which nerve is affected and from where does it arise?

A

Phrenic Nerve -> leads to respiratory distress on affected side and elevation of hemidiaphragm

Nerve roots C3-C5

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15
Q

What does failed carboxylation of glutamate residues of newly synthesized proteins in the liver indicate? Which patients are at risk of this?

A

Vitamin K deficiency - > (V. K is essential for hepatic microsomal carboxylases that convert glutamyl residues into gamm-carboxyglutamates) -> critical step for functioning of clotting factors VII, IX, and X, and activation of protein C and S

Neonates (limited hepatic reserve, poor intestinal flora, limited BA of VK in breast milk), Liver disease, Antibiotic use (destroys intestinal flora), malabsorption syndromes

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16
Q

How would serum values be affected in patients with inhaled-anesthetic hepatotoxicity?

A

ACUTE LIVER INJURY
1. increased PT (because def. of factor VII which has shortest half life)
2. increased aminotransferase levels
3. Leukocytosis + Eosinophilia (immune reaction)
(albumin + other clotting factors not affected because they have longer half-lives)

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17
Q

What is the difference between empathy and support?

A

Empathy requires the doc to walk in patient’s shows, e.g. “I can imagine how hard this must be.”

With support, doc does not claim to personally understand how the patient feels, “Yes you were really hurt by this incident”

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18
Q

What are the characteristics of signet-ring gastric carcinomas? Intestinal type adenocarcinomas?

A

Signet- Mucin containing cells, DIFFUSE involvement of stomach wall -> linitis plastica

Intestinal - resembles colon cancers, nodular, polyploid well demarcated masses (glands and columnar cells seen)

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19
Q

What condition causes rugal thickening with acid hypersecretion?

A

Zollinger-Ellison Syndrome

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20
Q

What is a comedocarcinoma?

A

Subtype of Ductal Carcinoma In Situ (DICS) of the breast with high grade cells in ducts, no basement membrane invasion and dystrophic calcification in center of ducts (necrosis)

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21
Q

What are the characteristics of a medullary carcinoma of the breast?

A

Solid sheets of vesicular, pleomorphic, mitotically active cells with significant lymphoplasmacytic infiltrate (around and w/in tumor) and a pushing, non-infiltrating border

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22
Q

What is the most common cause of spontaenous lobar hemorrhages (especially in >60 age group)? Where/how do these hemorrhages arise?

A

Cerebral amyloid angiopathy - spontaneous recurrent hemorrhages often in parietal/occipital lobes

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23
Q

How can you differentiate charcot-bouchard aneurysms from other pathologies that cause intracerebral hemorrhage?

A
  • Due to chronic HTN and involves deep brain structures (basal ganglia, thalamas, cerebellar nuclei, pons)
    vs. Cerebral amyloid angiopathy -> causes lobar hemorrhages (parietal, occipital) or Saccular Berry aneurysms -> SAH in circle of willis
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24
Q

What is the most common urea cycle deficiency and what is it associated with?

A

Ornithine transcarbamoylase (OTC) deficiency -> will have build up of ammonium and Carbamoyl phosphate, and increased urine orotic acid

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25
Q

What are the characteristics of carbamoyl phosphate synthase deficiency?

A

Increased ammonia -> neuro disorders

-Low levels of carbamoyl phosphate and no elevation in urine orotic acid

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26
Q

What carcinoma is associated with African children who have EBV infection? How does this appear and what leads to its development?

A

Burkitt Lymphoma -> intermediate sized lymphocytes with round nuclei and multiple prominent nucleoli, and vacuolated basophilic cytoplasm. High mitotic index and cell death rate. Diffuse macrophage distribution and “Starry Sky” appearance from debris clean up.

-t(8;14) of C-MYC oncogene to Ig Heavy chain -> TRANSCRIPTION ACTIVATOR

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27
Q

What results from a t(11;14) translocation?

A

Mantle Cell Lymphoma - Cyclin D from 11 moved to Ig heavy chain -> promoter of G1->S transition

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28
Q

What is the purpose of the GLUT2 transporter?

A

Export of glucose from liver, small intestine, and kidney into circulation and helps to control insulin secretion from the pancreas

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29
Q

What are they key side effects of Amiodarone and how are some of these treated?

A
  • Thyroid dysfunction (check TSH!) -> If hypothyroidism is induced, Tx w/ Levothyroxine
  • Corenal micro deposits
  • Blue gray skin
  • Hepatitis
  • Pulmonary fibrosis (can be life threatening)
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30
Q

What will be seen in a peripheral blood smear of a patient with bacterial meningitis -> sepsis?

A

Schistocytes from DIC

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31
Q

When are bite cells seen?

A

G6PD deficiency - splenic monocyte-macrophage system removing Heinz bodies from RBCs

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32
Q

What are the characteristics of X-linked agammaglobulinemia (Burton’s)?

A
  • Mutation in Burton Tyrosine Kinase -> failure of bone marrow pre-B cells (CD19, CD20) to develop
  • Low or absent B cells in peripheral blood
  • pan-hypogammaglobulinemia -> increased risk of infxn w/ pyogenic (encapsulated) bacteria
  • Susceptibility to enterovirus and Giardia lamblia (because no neutralizing/opsonizing Abs)
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33
Q

What are the regulatory pathways of the renin-angiotensin system?

A
  1. Macula Densa
  2. Intrarenal baroreceptors (respond to low pressure)
  3. Beta-adrenergic receptors in juxtaglomerular cells (beta-blockers like Propranolol will inhibit renin-AT system)
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34
Q

What facilitates glycogenolysis in muscle cells?

A
  1. Increased Calcium activates phosphorylase kinase to promote glycogen breakdown and glucose release (occurs with every muscle contraction)
  2. Increased cAMP only promotes glycogenolysis in response to Norepinephrine release (fight or flight action)
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35
Q

What leads to scalded skin syndrome?

A

Exfoliation exotoxin released by Staph. Aureus -> epidermolytic agents cleave desmoglein in desmosomes

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36
Q

How long is it typically required to have increased levels of serum beta-hcg following ovulation? Urine hcg?

A

Serum - 8 days post ovulation (1 IU/L)

Urine - 14 days post ovulation (20 IU/L)

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37
Q

How do you diagnose endogenous Cushing syndrome? What do the results from this test indicate?

A

Measure ACTH and cortisol levels + dexamethasone suppression test

  • High cortisol and high ACTH indicate ectopic secretion of ACTH (vs. primary adrenal disease)
  • If pituitary tumor -> reduction of Cortisol/ACTH from high dose dexamethasone
  • If nonpituitary tumor -> resistant to dexamethasone
  • Adrenal adenoma/carcinoma also resistant to dexamethasone (no change in low ACTH and high cortisol levels)
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38
Q

What are neurophysins?

A

Carrier proteins for oxytocin and vasopressin in posterior pituitary

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39
Q

What is beta-hydroxybutyrate?

A

Marker of insulin deficiency -> present in Type I diabetes mellitus

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40
Q

What is the MoA of flucytosine?

A

Inhibits DNA/RNA synthesis in Fungi

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41
Q

What will be greatly diminished on a molecular level if someone is deprived of folic acid? How can you circumvent this?

A

Folate is necessary for the de novo synthesis of dTMP by Thymidylate synthase.

Tx: By supplementing thymidine -> activate dTMP salvage pathway that uses Thymidine Kinase which will partially compensate for defective de novo synthesis

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42
Q

What process would lead to inflammation and partial necrosis of gall bladder wall? What is the risk of this condition?

A

Gall bladder outflow obstruction from stone -> Acute calculous cholecystitis (#1 complication of cholelithiasis)

Stone disrupts mucosal barrier -> epithelium damaged by bile and prostoglandins released -> inflammation, distension, ischemia -> necrosis -> final: bacterial invasion

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43
Q

What are myoclonic seizures and how best to treat? What should you NOT use?

A

Usually adolescent as part of JME -> brief, involuntary, jerking movements of upper extremity, with no loss of consciousness. Often soon after waking up.

Generalized epilepsy -> broad spectrum anticonvulsant -> Valproic acid (also lamotrigine, levetiracetam, topiramate)

DO NOT use Narrow spectrum anticonvulsants (Carbamazepine, Gabapentin, phenobarbital, phenytoin) as these may exacerbate symptoms.

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44
Q

What is the growth process of strawberry hemangiomas?

A

First increase with size as child grows, and then fade between 1-3 years of age, most are fully regressed by age 7

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45
Q

What is the main side effect of metronidazole? What is this drug usually used to treat?

A

Disulfiram like reaction -> inhibits alcohol oxidizing enzymes -> acetylaldehyde builds up -> flushing, headache, nausea+vomit with consumption of alcohol

Tx for Giardiasis, Trichomonas vaginitis, and bacterial vaginosis

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46
Q

What is a koilocyte?

A

Immature squamous cell with dense cytoplasma and halo + small vacuoles around a large nucleus -> sign of infection with HPV

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47
Q

Which lipid lowering drug can causes gouty arhtritis?

A

Niacin -> Hyperuricemia

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48
Q

What occurs from high levels of prolactinoma?

A

Galactorrhea and GnRH suppression -> Hypogonadism, anovulation, amenorrhea

Low estrogen -> Bone loss and vaginal dryness

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49
Q

What results from V. A and E toxicity?

A

A - acute: nausea/vomiting and vertigo; chronic: alopecia and dry skin, hyperlipidemia, hepatotox and visual problems (also a teratogen)

E - hemorrhagic stroke in elderly, and necrotizing enterocolitis in infants; hemolytic anemia

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50
Q

What is a method of providing anesthesia for a woman in labor if epidural cannot be done? How is it administered?

A

Pudendal nerve block - start intravaginally and inject lidocaine near the tip of the ischial spine (pudendal nerve is from S2-S4 and give sensory innervation to genitals and perineum and motor control of sphincter urethrae and anal spincter)

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51
Q

What are the first generation anti-histamines and their effects?

A

Chlorpheniramine and diphenhydramine - anti-histamine +
Anticholinergic -> pupillary dilation, dry mouth, urinary retention, constipation
Anti-alpha -> hypotension, postural dizziness
Anti-Serotonin -> appetite stimulation and weight gain

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52
Q

A patient develops vomiting and lethargy after 1 full day of fasting, and develops seizure after arriving to the hospital. Physical exam shows a mildly enlarged liver. What is deficient in this patient? What serum values would be present?

A

Acetyl-CoA dehydrogenase -> after 16-24 hrs tissues depend on lipid derived fuels for energy. Without this enzyme, first step of beta-oxidation of fatty acids cannot occur

Serum ketones would be low and blood glucose low (can’t undergo gluconeogenesis without energy)

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53
Q

What is characteristic of osteoclasts in paget’s disease of the bone? What Factors are most important for differentiation and development of these cells?

A

Very large w/ up to 100 nuclei and positive for tartate-resistent acid phosphatase

Factors -> M-CSF (macrophage colony stimulating facotr) and RANK-L

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54
Q

Which solute is crucial for generating a high concentration gradient in the nephron in response to vasopressin, and where in the nephron does this occur?

A

ADH -> acts on V1 and V2 receptors in the collecting duct, and greatest concentration of urine occurs in the MEDULLARY collecting duct because of increased passive UREA transporters in this region (other areas of collecting duct, DCT and thick loop of Henle are impermeable to Urea)

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55
Q

What is the best medication for women with PCOS getting treated for infertility? For hirsituism and acne?

A

Clomiphene - Selective estrogen receptor modulator -> prevents negative feedback inhibition on hypothalamus by circulating estrogen -> increased FSH and LH -> ovulation

Spironolactone -> androgen receptor antagonist

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56
Q

What is the cause of increased bleeding in patients with renal dysfunction? How do you improve this problem?

A

Accumulation of uremic toxins -> impair platelet aggregation and adhesion

Tx = dialysis

57
Q

What is Pyrazinamide? Provide some key characteristics. What other compounds is it associated with and how do they differ?

A

Anti-mycobacterial drug that works best at acidic pHs (i.e. within phagolysosomes of macrophages) -> most bacteriocidal to M. Tuberculosis organisms engulfed by macrophages

Other anti-TB drugs -> Isoniazid, ethambutol, rifampin have relatively better activity against extracellular TB

58
Q

What are the main complications of statin therapy?

A

Myopathy and HEPATOTOXICITY (very serious in about 1% of patients -> discontinue drug if very high AST/ALT)

59
Q

What serum markers can be diagnostic for celiac disease?

A

IgA anti-endomysial and anti-tissue transglutaminase antibodies

60
Q

What is the best way to appreciate S3 heart sounds?

A

Have the patient lie in the left lateral decubitus position, then auscultate with the bell of the stethoscope lightly pressed at the apex. Have patient exhale completely to decrease breath sounds and bring heart closer to chest wall.

61
Q

What heart sounds is the bearing down phase of the valsalva maneuver helpful for differentiating?

A

Bearing down decreases venous return to left side of the heart decreasing LV volume and BP -> MVP and hypertrophic cardiomyopathy murmurs heard better while aortic stenosis diminished

62
Q

What is the most sensitive test for menopause?

A

Elevated FSH levels (because decreased feedback inhibition from estrogen; rise in LH later in menopause)

63
Q

What are the histological and EM characteristics of a carcinoid tumor? What do these cells originate from?

A

Nests of many small cells with scant eosinophilic cytoplasm and large round basophilic nuclei -> minimal to no variation in shape and size of cells

EM = dense core granules containing secretory hormone-like substances and vasoactive peptides

Result from malignant transformation of enterochromaffin (endocrine) cells of intestinal mucosa

64
Q

What are the common signs of primary biliary cirrhosis? What is this disease process similar to?

A
  • Intense generalized pruritis, high alkaline phosphatase, and high titers of anti-mitochondrial Abs
  • Interlobar bile ducts destroyed by granulomatous inflammation and heavy portal tract infiltration by macrophages, lymphocytes, plasma cells and eosinophils
  • Similar to Graft vs. Host disease (immunological injury)
65
Q

What is Leucovorin used for?

A

Folinic acid, Methotrexate overdose

66
Q

How does the diphtheria vaccine work?

A

DPT - toxoid vaccine - stimulates production of neutralizing antibodies against B subunit of the diphtheria exotoxin -> antibody binding prevents exotoxin from attaching to host cell membrane

67
Q

What is the function of ristocetin? How may this be useful?

A

-Activates GP Ib-IX receptor on platelets, making them available for vWF binding -> if vWF is decreased, there is poor platelet aggregation in the presence of ristocetin

68
Q

Which broad spectrum antibiotics are useful for anaerobic bacteria?

A

Metronidazole (bottom half), Clindamycin (Top half), Carbapanems, Penicillin+Tazobactam (especially if beta lactamase resistant)

69
Q

What is subacute sclerosing panencephalitis?

A

Rare complication of measles in peds/adults several years post infection -> ataxia, myoclonus, visual problems, personality changes

  • Caused by form of measles with absent matrix proteins
  • Accumulation of viral nucleocapsids in neurons/oligodendrocytes
  • High titers of measles antibodies in patient (e.g. hemagglutinin)
70
Q

What is supranuclear palsy?

A

Form of parkinson’s from neurodegeneration of midbrain and subcortical white matter -> rapidly progressive gait dysfunction and falls, executive function loss, and vertical gaze palsy
-Biopsy-> deposits of abnormally phosphorylated tau proteins

71
Q

What condition results in a uterine mass with a “bunch of grapes” appearance, and what needs to be monitored in these patients and why?

A

Hydaditiform Moles -> monitor beta-hCG b/c excess hCG stimulates ovarian growth and formation of theca-lutein cysts + invasive mole can penetrate uterine wall and form choriocarcinoma (high beta-hCG with invasive moles/choriocarcinoma)

72
Q

What does elevated AFP in a pregnant woman suggest?

A
  • Fetal neural tube defects

- Underestimate of gestational age, twin gestation, and abdominal wall defects also possible

73
Q

What is carcinoembryonic antigen (CEA) used to monitor?

A

Colorectal carcinoma

74
Q

What is the first enzyme of the glycolytic pathway? What is unique about this enzyme in certain tissues?

A
  • Hexokinase in most tissues
  • Glucokinase in pancreatic beta cells -> has much higher Km and less sensitive to G6P inhibition -> thus it functions as a glucose sensor and deficiencies could lead to a mature onset diabetes
75
Q

What compound has the fastest rate of metabolism in the glycolytic pathway in hepatocytes and why?

A

Fructose-1-Phosphate -> bypasses key enzyme phosphofructokinase which is a key regulatory enzyme of glycolysis (aldose B can convert F1P into DHAP and glyceraldehyde)

76
Q

A patient suffers from bronchial asthma and recurrent transient pulmonary infiltrates. Blood count shows eosinophilia and CT shows bronchiectasis, what is the cause?

A

Aspergillus fumigatus –> causing allergic bronchopulmonary aspergillosis (ABPA)

77
Q

What are the symptoms of strongyloidiasis?

A
  • Cough, asthma like bronchospasm and hemoptysis
  • Transient pneumonia
  • Chronic lung involvement rarely will cause -> features of obstructive/restrictive disease (not bronchiectasis)
78
Q

What is the most commonly used agent for long term anticoagulation to prevent venous thrombosis and PE? Acute management?

A

Warfarin -> given orally, use long term

Heparin -> given by IV, use in acute setting

79
Q

What occurs with hyperacute, acute and chronic graft rejection in lung transplant?

A

Hyperacute (minutes) - graft blood vessel spasm and diffuse intravascular coagulation -> ischemia
Acute (1-2 weeks) - T-cell mediated vascular damage
Chronic (months-years) - inflammation and fibrosis of small bronchioles (bronchiolitis obliterans) -> (NOTE: this is in contrast to other tissues like renal transplant which have primarily vascular obliteration)

80
Q

What will happen to the left and right eye if the left optic nerve is cut and a light is shined in the left eye?

A

No change -> lack of pupillary light reflex

81
Q

How do you calculate renal blood flow (RBF)?

A

RBF = RPF / (1 - Hct)

Note RPF = PAH clearance

82
Q

Which drugs are used as appetite suppressants and what is the major risk in using them

A

Fenfluramine, dexfenfluramine, and phentermine for > 3 months –> secondary pulmonary HTN

83
Q

What neoplasms can cause subacute cerebellar degeneration?

A

Paraneoplastic Syndromes from either small cell lung cancer of Breast/ovarian/uterine cancers -> release of Anti-Yo, anti-P/Q, Anti-Hu antibodies which cross react with Purkinje Neuron antigens

84
Q

What paraneoplastic syndromes can result from small cell lung cancer?

A

Cushing syndrome (ACTH or CRH), SIADH (ectopic vasopressin production), Lambert Eaton myasthenic syndrome (Ab to presynaptic voltage gated Ca channels) and subacute cerebellar degeneration (Anti Yo, Anti PQ anti-Hu antibodies)

85
Q

What abnormality leads to tetralogy of Fallot? What else is caused by this?

A

Abnormal neural crest migration -> Problems with septation of aorta and pulmonary vessels (normal spiral migration disrupted)

Also can cause Truncus arteriosus and Transposition of great vessels

86
Q

What is impaired vision in an HIV infected person most commonly associated with, and how would you treat? What are the side effects of these treatments

A

CMV retinitis (tx in order of precedence)

  1. Ganciclovir - severe neutropenia, do not give to HIV patient on Zidovudine!
  2. Foscarnet - induce renal wasting of magnesium and chelates Calcium -> hypomagnesia/calcemia -> Seizures
  3. Cidofovir -> Nephrotoxicity
87
Q

What are the side effects of lamivudine?

A

peripheral neuropathy and lactic acidosis

88
Q

What does a chest XRay with a round density with air-fluid levels in lower lung lobes indicate? What can cause this?

A
  • Lung abscess (fluid partially drains if abscess connected to air cavity -> air+fluid filled cavity formed)
  • Release of lysosomal enzymes by PMNs and Macrophages can lead to destruction of lung parenchyma surrounding the infection site -> abscess formation
89
Q

Besides morphological changes, what else can occur from pathological ventricular hypertrophy?

A

Prolonged hemodynamic overload -> abnormal up-regulation or re-expression of fetal proteins from both atrial & ventricular myocytes -> ANP + BNP release -> facilitates natriuresis and diuresis (BNP to diagnose systolic and diastolic CHF)

90
Q

How does pulmonary silicosis appear? Berryliosis?

A

Nodular densities and egg shell calcifications on hilar nodes

Nodular infiltrates, enlarged lymph nodes, non caseating granulomas (similar to Sarcoidosis)

91
Q

How do CFTR mutations manifest in mucous producing glands (respiratory + gastric) vs. sweat glands?

A

Mucus - Normally CFTR increases Cl- secretion to also increase Na+ and H2O in mucus, but with CF -> Cl- can’t be secreted -> increased reabsorption of Na+ and H2O -> dehydrated mucus

Sweat - Normally CFTR decrease salt content of sweat by absorbing Cl- back in , but with CF -> Cl- can’t be reabsorbed -> Hypertonic sweat with high Cl- content -> free water lost

92
Q

Which biochemical synthetic processes is Tetrahydrobiopterin (BH4) involved in?

A

BH4 is cofactor in synthesis of Tyrosine (from Phe), DOPA (which makes catecholamines and melanin), Serotonin (from tryptophan), and Nitric Oxide

93
Q

What is the most common defect in achondroplasia?

A

Mutation of fibroblast growth factor receptor 3 (FGF-R 3) at epiphyseal growth plate -> inhibited growth of CHONDROCYTES at epiphyseal growth plate

94
Q

What is serum marker CA 19-9 for?

A

74% of patients with pancreatic cancer have this

95
Q

What causes increased levels of DHEA?

A

Excess production of adrenal antigens as in adrenal neoplasia

96
Q

What is the cause of intestinal atresia distal to the duodenum in a newborn? What results from this process?

A

Vascular accidents in utero -> ischemia of bowel -> narrowing/obliteration of lumen (usually ileum)

If major vessel occluded (SMA) -> large area of necrosis -> blind ending proximal jejunum + dissolution of long section of bowel and its mesentery -> terminal ileum distal to occlusion assumes spiral configuration around ileocecal valve

97
Q

What is the presentation for acute hemolytic transfusion reaction, and what type of reaction is this?

A
  • Fevers/chills, hypotension, dyspnea, cheast+back pain, and hemoglobinuria
  • May develop DIC and renal failure
  • Type II hypersensitivity reaction
98
Q

What occurs in type II hypersensitivity reactions and what are examples of this?

A

Type II = Cy-two-toxic (cytotoxic)

  • IgG and IgM autoantibodies -> phagocytic response and complement mediated cell toxicity
    e. g. Autoimmune hemolytic anemia, Goodpasture’s syndrome, acute hemolytic transfusion reaction
99
Q

Which areas of the body are usually involved in postmenopausal osteoporosis and what serum PTH and Calcium levels would you see in primary osteoporosis?

A
  • Cancellous bone ( vertebral column, distal radius, hip and neck of femur)
  • PTH and Ca usually normal range
100
Q

When do you usually see high serum PTH and low Calcium?`

A

Renal failure or vitamin D deficiency

101
Q

How do you calculate cardiac output?

A

CO = SV x HR

CO = O2 consumption / arteriovenous O2 difference

102
Q

How can you identify AML on blood smear?

A
  • Many myeloblasts (large cells with basophilic cytoplasm)
  • Folded/bilobed nuclei in these cells
  • Auer rods which stain for peroxidase
103
Q

How do you identify Hairy cell leukemia?

A
  • Proliferation of mature CD20+ B cell precursors with cytoplasmic processes
  • Cells are positive for TRAP (Tartrate resistant acid phosphatase)
  • Splenomegaly (from RED PULP expansion)
  • Dry tap w/ bone marrow aspiration
104
Q

Which drug as a monotherapy increases triglyceride levels?

A

Cholestyramine (from hepatic increase in triglyc. and VLDL production)

105
Q

What are the main effects and side effects of Niacin use?

A
  • Decreases VLDL conversion to LDL and decreases triglycerides
  • Increases HDL

SE: Flushing (decreases w/ NSAIDs or long term use), Hyperglycemia and Hyperuricemia (precipitate gout)

106
Q

What is 5-hydroxyindoleacetic acid?

A

Metabolite of serotonin that is increased in urine excretion with carcinoid syndrome

107
Q

What effects would carcinoid tumors in the liver have?

A

Fibrous intimal thickening and endocardial plaques limited to the right heart (lungs metabolize serotonin to 5-HIAA so left heart not affected)

108
Q

What effects does elevated homocysteine levels have?

A

Arterial and venous thrombosis and atherosclerosis

109
Q

What is the intrapleural pressure at FRC?

A

-5 cm H2O

110
Q

Which cells undergo hyperplasia and hypertrophy with severe stenosis of renal artery?

A

Modified smooth muscles cells of afferent arteriole (Juxta-Glomerular -JG- apparatus cells)

111
Q

What are the characteristics of drugs with high intrinsic hepatic clearance?

A

Highly lipophilic and high volume of distribution

112
Q

What is most likely to occur during the first week of primary exposure to TB? 2-4 weeks post infection?

A
  1. Intracellular bacterial proliferation

2. antigen carrying macrophages/dendritic cells migrate to lymph nodes and induce Helper T-cell response

113
Q

What is the inheritance pattern for G6PD deficiency?

A

X-linked Recessive (note males are usually affected)

114
Q

Where should catheters be inserted for thoracocentesis?

A

2 intercostal spaces above pleural border (depending on area)
-Midclavicular (between 5-7) Midaxillary (between 7-9) Paravertebral (between 9-11)

115
Q

What is apoplexy? Where can it occur?

A

Greek apopleksia “a striking away’ -> hemorrhage within internal organs

  • Pituitary adenoma hemorrhage
  • Cerebral hemorrhage
  • Ovarian (chocolate cyst)
116
Q

Which drugs given together can dramatically increase the formation of gallstones, why?

A

Fibrates (gemfibrozil) and bile acid binding resins (cholestyramine) both increase the cholesterol content in bile -> increasing risk for cholesterol gall stones

117
Q

What complication can arise in a patient with acute pancreatitis weeks after the inciting insult?

A

Pancreatic pseudocyst formed by granulation tissue around fluid with high pancreatic enzyme content (contrast with true cyst which is lined by epithelial cells) usually in the lesser sac (behind stomach)
- usually 4-6 weeks after episode of acute pancreatitis

118
Q

What leads to duchenne and becker muscular dystrophy?

A

Deletions of dystrophin gene (for dystrophin protein on X chromosome p21) - a structural protein component of muscle fibers

119
Q

What organ structure would be affected by a stab wound in the 5th intercostal space along the midclavicular line?

A

Lung

120
Q

What compound will lead to insulin resistance in the mother and why? How may Gestational Diabetes Mellitus develop?

A

Human Placental Lactogen (released by syncytiotrophoblast, similar to prolactin and GH) -> increases insulin secretion -> increased insulin resistance
(lipolysis and proteolysis also increased to give mother energy, shunting extra glucose and amino acids to baby)

When mom’s pancreatic function can’t overcome insulin resistance -> GDM develops

121
Q

What should fever and sore throat in a patient getting treated for hyperthyroidism raise concerns for? What should be the first step in management?

A

Thionamide-induced agranulocytosis (Meth., PTU) -> major side effect of AGRANULOCYTOSIS in both (PMN

122
Q

What pathophysiological factors are present in isolated diastolic heart failure?

A

Increased LV end diastolic pressure, and normal LV end diastolic volume and ejection fraction (EF not affected because there is no problem with contractility, just decreased LV wall compliance)

123
Q

What are the characteristics of ophthalmopathy in Grave’s disease? How do you treat this?

A

Eye irritation, diplopia, bilateral eye redness, severe proptosis,

Treat with high-dose glucocorticoids because it is inflammatory infiltration that leads to this problem!!

124
Q

What leads to defective mineralization of bone? Defective bone matrix formation?

A

Def. mineralization = Vit. D deficiency

Def. MATRIX = OSTEOGENESIS IMPERFECTA (AD inheritance) -> because it is a type I collagen problem so the matrix is weak

125
Q

Where in the nephron do you find the lowest osmolarity and why?

A

DCT (because in PCT water is reabsorbed with electrolytes vs. thick ascending loop which is impermeable to water -> decreasing osmolarity of fluid entering DCT, which is also relatively impermeable )

126
Q

What is cystic medial degeneration and what can cause this?

A

Myxomatous changes in media of large arteries -> fragmentation of elastic tissues -> separation of elastic and fibromuscular components of tunic media

  1. Marfan’s -> AD defect in Fibrillin-1 protein scaffold -> aortic aneurysm and dissection
  2. beta-aminopropionitrile - found in some sweat peas -> changes elasticity of aorta mimicking myxomatous degeneration of Marfan’s
127
Q

What pathogenesis leads to Berry aneurysm?

A

Multifactorial including: hemodynamic stress, HTN, and connective tissue disorders predispose (Type IV ehler danlos -> defect in Type III collagen)

NOTE - there is NO association with Marfan’s or myxomatous degeneration of tunica media

128
Q

What is the Winter’s formula?

A

Compensation for metabolic acidosis:

Arterial PaCO2 = 1.5 (serum bicarb) + 8 +/- 2

129
Q

What factor may be key in diagnosing aplastic anemia?

A

absence of splenomegaly (a patient with pancytopenia and splenomegaly is unlikely to have aplastic anemia)

130
Q

What sort of action does methadone have?

A

FULL Mu receptor AGONIST (partial agonists increase risk of withdrawal symptoms)

131
Q

What are some of the NNRTIs and key side effects?

A

Nevirapine (CYP inducer), Efavirenz, and Delavirdine

Major risk for hepatic failure + encephalopathy and SJS

132
Q

What are the features of anti-phospholipid antibody syndrome?

A
  1. Venous/Arterial thromboembolic disease (DVT, PE, Stroke/TIA)
  2. Adverse pregnancy outcomes (unexplained embryo/fetus loss)
  3. Lupus anticoagulant effect (paradoxical PTT prolongation, w/ no increase in bleeding)
133
Q

What problem can result in the child, from poorly controlled diabetes in the mother?

A

Caudal regression syndrome -> agenesis of sacrum and occasionally lumbar spine

134
Q

What does cord factor contribute to?

A

Virulence of TB -> inactivates PMNs, damages mitochondria, and releases TNF. Absolutely necessary for TB to cause disease.

135
Q

What is the preferred mode of breathing for restrictive diseases vs. asthma/COPD?

A

Restrictive (pulmonary fibrosis) - Rapid shallow breathing to minimize work of breathing (work of breathing already elevated, but follows similar curve to normal breathing)

COPD/Asthma - Slow deep breathing to minimize work

136
Q

Which compound functions as a central regulator of iron homeostasis and where is it produced?

A

Hepcidin, from the Liver ( low hepcidin increases intestinal iron absorption and stimulates iron release by macrophages)

137
Q

What drug would be preferred in a patient with pain who has peptic ulcer disease and why?

A

Celecoxib (Selective COX2 inhibitor) -> because COX 1 inhibition is what causes the GI adverse effects of NSAIDs

138
Q

What is seen histologically in the case of acute viral hepatitis? What is the most common cause of this in young adults?

A
  1. Diffuse ballooning degeneration (Hepatocyte swelling)
  2. Mononuclear cell infiltrates
  3. Councilman bodies (Eosinophilic apoptotic hepatocytes)

HAV most common for this group

139
Q

What are the causes of hepatic abscess in the 1st vs. 3rd world?

A

3rd - Parasitic infections (Entamoeba histolytica, echinococcal)

1st - Bacterial infection (ascending cholangitis, Portal vein from bowel source, hepatic artery from systemic hematogenous spread, penetrating trauma/injury, adjacent sources like peritonitis)

USMLE Wrong Answer Facts (9 decks)

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