High Yields Week 4 Flashcards
What are the three phases of disease progression in Lyme disease (Borrelia burgdorferi infection)?
- Early phase - flu-like symptoms and erythema chronicum migrans (target looking rash)
- Early disseminated phase - CNS involvement (facial palsy) and/or cardiac involvement (AB nodal block)
- Late Lyme disease - asymmetric arthritis (typically a single knee joint) and/or encephalopathy with memory/mood changes
What are common side effects of nondihydropyridine calcium channel blockers (diltiazem, verapamil)?
Constipation
Bradycardia
AV conduction block (↓ chronotropic effect)
Worsening of HF in patients with reduced left ventricular systolic function (↓ inotropic effect)
What are the highlights of the three phases of syphilis (Treponema pallidum infection)?
Primary (3-5 wks) - painless chancre on genitals
Secondary (5-10 wks) - Diffuse macular rash that includes palms and soles, condylomata (gray wartlike lesions in genital/perianal area)
Tertiary (years later) - Gummas (white-gray rubbery lesion), ascending aortic aneurysm (vasa vasorum destruction), Argyll Robertson pupil (constricts w/ accommodation but not reactive to light)
Neurosyphilis (tabes dorsalis, “general paresis) can occur at ANY stage, but most common in tertiary
What is McCune-Albright syndrome?
Characterized by a triad of:
- fibrous dysplasia of the bone (bony abnormalities, scar tissue in bone)
- endocrine abnormalities (such as hyperthyroidism)
- cafe-au-lait spots
- precocious puberty in girls
Results from a mosaic G-protein signaling mutation causing constituitive activation of the G-protein/cAMP/adenylate cyclase signaling pathway
What is the mechanism of action of SSRIs?
Inhibition of serotonin reuptake into the presynaptic neuron, increasing the amount of serotonin in the synaptic space
This is done by blocking the “serotonin transporter”
A 45 y/o homeless man with a history of alcohol abuse presents to the ER with decreased urine output (oliguria), flank pain, metabolic acidosis and multiple calcium oxalate crystals in the urine. Disease/Dx?
Ethylene glycol ingestion
Causes metabolic acidosis, kidney stones and acute tubular necrosis (glycolic acid metabolite of ethylene glycol is toxic to renal tubules)
What is the most common type of thyroid cancer?
Papillary thyroid cancer
On histology - psammoma bodies, nuclear grooves and “Orphan Annie”
What is the inheritance pattern of MEN syndromes?
Autosomal dominant
“All MEN are dominant”
What is classically seen in MEN1?
3 P’s
Parathyroid tumors (↑ PTH → hypercalcemia Pituitary tumors (prolactin, visual/mass effects) Pancreatic endocrine tumors (usually gastrinomas → Zollinger-Ellison syndrome)
What is classically seen in MEN2A?
2 P’s
Medullary thyroid cancer (calcitonin)
Pheochromocytoma
Parathyroid hyperplasia
What is classically seen in MEN2B?
1 P
Medullary thyroid cancer (calcitonin)
Pheochromocytoma
Mucosal neuromas (skin colored lesions on lips/tongue)
Marfanoid habitus (long arms, long fingers, tall)
A 34 yo man presents with blue-black spots in his sclera and around his ears. He states that his urine turned black overnight after he forgot to flush the toilet. Disease/Dx?
Alkaptonuria
Autosomal recessive with deficient homogenistic acid dehydrogenase
This blocks the metabolism of tyrosine and causes an accumulation of homogenistic acid which is responsible for blue-black pigmentation discolorations
A 55 yo man presents with complaints of difficulty getting up from chairs and climbing stairs, diplopia, dry mouth and impotence. On physical exam he has decreased deep tendon reflexes. Chest x-ray notable for an irregular round mass in the upper lobe of his right lung. Disease/Dx?
Lambert-Eaton myasthenic syndrome secondary to small-cell carcinoma of the lung (classic association)
Lamert-Easton myasthenic syndrome is due to autoantibodies against the Ca2+ channels in the presynaptic terminal membrane that participate in acetylcholine release
Causes
- proximal muscle weakness
- cranial nerve involvement (diplopia, dysphagia)
- autonomic dysfunction (dry mouth, impotence)
In the presence of ADH, where is the most concentrated fluid in the nephron? the most dilute fluid in the nephron?
Most concentrated → Collecting ducts (ADH mediates water absorption here, concentrating the urine)
Most dilute → thick ascending limb of Henle and distal convoluted tubule (impermeable to water with lots of electrolyte reabsorption, diluting the urine)
Where is airway resistance highest in the lungs?
The first 10 generations bronchi (small/medium bronchi)
This is due to all the turbulent airflow in these regions
As a class of drugs, what is the most common adverse effect associated with atypical (2nd generation) antipsychotics?
Metabolic adverse effects
- WEIGHT GAIN
- dyslipidemia
- hyperglycemia
- increased risk of diabetes
What main veins do the right and left ovarian veins drain into?
Right ovarian vein → IVC
Left ovarian vein → left renal vein (then draining to IVC)
This mimics the testicular veins
What causes the green discoloration seen in pus or coughed up sputum during common bacterial infections (such as Strep pneumo)?
The presence of myeloperoxidase
Myeloperoxidase is a blue-green enzyme released from neutrophils during an infection
What drug should be administered for acute exacerbations of COPD or asthma?
Beta-adrenergic agonists
B2-mediated relaxation of smooth muscle causes bronchodilation, opening the airways and providing relief of obstructive lung disease
Pancreatic beta cells contain adrenergic receptors a2 and B2. What are the effects of stimulation of these receptors on the pancreatic beta cells?
a2 stimulation → inhibits insulin secretion
B2 stimulation → promotes insulin secretion
What is the most common cause of death in tricyclic antidepressant (amitriptyline) overdose?
Cardiac arrhythmias and refractory hypotension
(due to inhibition of fast sodium channels in cardiac myocytes)
Treatment of TCA overdose is NaHCO3 (sodium bicarb)
What does the presence of Howell-Jolly bodies suggest?
Decreased or absent splenic function
Howell-Jolly bodies are RBCs that DNA remnant inclusions that are normally removed by the spleen during circulation
What do the RBCs of a patient with lead poisoning look like on a peripheral blood smear? on bone marrow aspirate?
Peripheral blood smear - RBCs with basophilic stippling (due to RNA aggregation)
Bone marrow aspirate - RBCs with ring sideroblasts (due to iron deposition)
What is the most common type of cancer in people chronically exposed to asbestos?
Lung cancer (bronchogenic carcinoma) is most common
Mesothelioma (pleural cancer) is second most common
Lung cancer > Mesothelioma
What cells does parvovirus B19 infect and replicate in?
Erythroid precursor cells in the bone marrow
This is why sickle cell patients develop aplastic crisis and immunosuppressed patients can develop chronic anemia with a parvovirus B19 infection
What type of morphology would be seen in an organ transplant rejection that has occurred slowly over months to years?
- Vascular wall thickening and luminal narrowing
- Interstitial fibrosis and parenchymal atrophy
TLDR - low grade, chronic immune response causing fibrosis to the organ; neutrophils/dense lymphocytic infiltrate will not be seen (those are seen in hyperacute and acute organ rejection)
What is indicative of intense regions of bright pink following acid-Schiff (PAS) stain on an intestinal biopsy of a 45 yo man presenting with abdominal discomfort, loose stools and recent weight loss?
Troperyma whippelii infection causing Whipple disease
PAS stain in conjunction with diastase stains the glycoprotein present in the cell walls of the gram-positive bacteria bright pink/magenta
Where do cranial nerves III, IV, V1 and VI exit the skull?
All of these nerves exit via the superior orbital fissure and provide motor (III, IV, VI) and sensory (V1) innervation to the eye
Describe first-order kinetics vs. zero-order kinetics in drug metabolism.
First-order - a constant PROPORTION of drug is metabolized per unit time - exponential metabolism
(ex. 50% of a drug metabolized per hour regardless of the drug concentration)
Zero-order - a constant AMOUNT of drug is metabolized per unit time - linear metabolism
(ex. 5mg of a drug is metabolized per hour regardless of drug concentration)
What is isolated systolic hypertension?
Systolic BP > 140 mm Hg + Diastolic BP 60yo, can be caused by increased arterial/aortic stiffness
A 35 y/o male presents with complaints that he cannot extent his right wrist. He does not recall any recent traumatic injury. He has a history of asthma. Lab values show eosinophilia and positive antibodies against neutrophil myeloperoxidase. Disease/Dx?
Eosinophilic granulomatosis with polyangiitis (Churg-Strauss)
Small vessel vasculitis with MPO-ANCA/p-ANCA +
People with narcolepsy lack what 2 neuropeptides?
Hypocretin-1 (Orexin-A)
Hypocretin-2 (Orexin-B)
These neuropeptides function to promote wakefulness and inhibit REM-sleep → thus without these you would be very sleepy
In addition to skin lesions, where else can Kaposi’s sarcoma (caused by HHV-8) manifest?
Lungs and GI tract (diarrhea)
Remember, KS is typically found in people with HIV
What is characteristic on histology of pancreatic beta cells in patients with Type 2 DM?
Islet amyloid polypeptide deposits
Type 1 DM has leukocytic infiltrate
What is the general pathogenesis of Paget disease of the bone?
Osteoclast dominant, increased bone resorption
↓
Osteoclast + Osteoblast activity, creation of disorganized, abnormal bone
↓
Osteoblast dominant, haphazard creation of bone with a mosaic pattern and prominent cement lines
In order of decreasing involvement, what vessels are most commonly involved in development of atherosclerotic plaques?
Abdominal aorta > coronary arteries > popliteal arteries > internal carotid arteries
Abdominal aorta is the most common/involved!
What are the structural components of MHC Class I and MHC Class II cell surface molecules and what type of cells do they present antigen to?
MHC Class I
- heavy chain and B2-microglobulin
- present to CD8+ (cytotoxic T cells)
MHC Class II
- alpha and beta polypeptide chains
- present to CD4+ (helper T cells)
What is the most important factor for determining cancer prognosis?
Stage - indicates extent of tumor expansion
Grade indicates tumor differentiation and is less important in prognosis
What are the four rotator cuff muscles and what are their physiologic functions on shoulder movement?
Supraspinatus m. → Abduction
Infraspinatus m. → External rotation
Teres minor m. → Adduction and external rotation
Subscapularis m. → Adduction and internal rotation
What is the key autoantibody, histologic characteristic and clinical finding of bullous pemphigoid?
Antibodies against hemidesmosomes
Histology → subepidermal cleavage causing separation of the epidermis from the dermis
Clinical → TENSE blisters (look like they are going to pop)
What is the key autoantibody, histologic characteristic and clinical finding of pemphigus vulgaris?
Antibodies against desmosomes
Histology → intraepithelial cleavage with acantholysis
Clinical → FLACCID blisters with oral/mucosal involvement
What is the most common cause of bacterial meningitis in adults of all ages?
Strep pneumoniae
2nd most common is Neisseria meningitidis
What is the child version of antisocial personality disorder?
Conduct disorder
Must be 18 years old
What is the characteristic murmur caused by a patent ductus arteriosus?
Continuous, machine-like murmur
occurs through both diastole and systole
What can occur in patients who receive a massive quantity of blood transfusion (5-6 liters) due to citrate, a substance added to stored blood?
Hypocalcemia
The citrate contained in stored blood can chelate serum calcium in the recipient of the blood → can lead to symptoms of hypocalcemia such as paresthesias
What renal complication can result from chronic hemolysis?
Hemosiderosis - iron deposition in the kidney
This can cause interfere with proximal tubule function and cause interstitial scarring and cortical infarcts
What is the most common cause of retinitis in an HIV+ patient?
CMV infection
treated with ganciclovir
Where are cysts commonly seen in autosomal dominant polycystic kidney disease?
Kidneys - causes kidney failure, hematuria, flank pain
Liver
“Brain” - cerebral aneurysms that may rupture
Doesn’t typically present until adult age 30s-50s
Which artery courses with the radial nerve down the posterior aspect of the humerus and can be co-injured in the event of a mid-shaft humerus fracture?
Deep brachial artery
What key vitamins/molecules are created by the normal bacterial flora in the small intestines?
Vitamin K and Folate
What is tardive dyskinesia?
A movement disorder typically caused by long-term treatment with antipsychotics for schizophrenia
It is characterized by repetitive, rhythmic, involuntary movements of the tongues, lips, face, trunk and hands/feet
Ex - facial grimacing, tongue movements, lip smacking, puckering
What is the mechanism of hemolysis seen in diseases such as hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura and DIC?
These diseases result in microangiopathic hemolytic anemia
This is caused by some type of process either damage to the endothelial layer of small blood vessels or widespread clotting, but in both cases it results in fibrin deposition and platelet aggregation in smaller vessels
As blood flows past these obstructions in small vessels, it is sliced up leading to intravascular hemolysis and characteristic schistocytes (‘helmet cells’)
What is the underlying defect causing ‘white’, hypopigmented spots on people with vitiligo?
Loss of epidermal melanocytes
causing a complete absence of melanin pigment
A 35 yo pregnant woman presents with pain and tingling in her first three digits on both hands. On physical exam she has thenar atrophy. What is the most likely diagnosis?
Carpal tunnel syndrome
Caused by compression of the MEDIAN NERVE within the carpal tunnel and often appears BILATERALLY
What enzymes require thiamine to function that are particularly problematic in chronic alcoholic patients?
Pyruvate dehydrogenase - Pyruvate → Acetyl CoA
a-Ketoglutarate - a-Ketoglutarate → Succinyl CoA
Alcoholics are classically deficient in thiamine (vitamin B1) which shuts down the TCA cycle and results in Wernicke encephalopathy
During a surgery on a newborn, tan fat-containing tissue is found around the kidneys and adrenal glands. What is the function of this tan colored fat?
Brown adipose tissue produces heat in newborns, preventing hypothermia
Its brown color is due to a high amount of mitochondria which utilize the ETC to produce HEAT instead of ATP
TLDR - in lieu of producing ATP, brown fat mitochondria produce heat
What is a nonlactose-fermenting, oxidase-positive, motile, gram-negative rod that causes otitis externa?
Pseudomonas aeruginosa
What two chronic conditions cause hyaline arteriolosclerosis in medium to small sized arteries (particularly in the kidney)?
Hypertension and Diabetes Mellitus (poorly controlled or untreated in both cases)
Hyaline deposition will stain pink with periodic acid-Schiff (PAS) stain
What two transporters allow for calcium efflux from cardiac myocytes, allowing for myocyte relaxation?
Na+/Ca2+-exchange pump
Sarcoplasmic reticulum Ca2+-ATPase pump (SERCA)
Calcium must be pumped out of the cytoplasm to allow for cardiac muscle relaxation
What lab test should be ordered when finding a xanthoma on physical exam?
Serum lipids and blood glucose level
to investigate for hyperlipidemia, dyslipidemia and potential insulin resistance
What vein can experience thrombosis/blood clot formation due to pancreatic inflammation?
Splenic vein
The splenic vein runs along the posterior surface of the pancreas and can develop a blood clot from pancreatic inflammation
A baby presenting with bilateral spastic paresis, abnormal involuntary movements and significantly elevated arginine levels in plasma and CSF likely has a problem with what metabolic pathway?
Urea cycle
This pathway breaks down nitrogenous waste (ammonia) from protein metabolism and turns it into urea for excretion from the body in urine
What acid-base disorder is typically seen at very high altitudes acutely?
Respiratory alkalosis (low PaCO2) with compensatory drop in HCO3- → caused by hypoxemia (low PaO2) and resulting hyperventilation
What inheritance pattern is seen in glucose-6-phosphate dehydrogenase (G6PD) deficiency?
X-linked recessive
Males are affected, females are generally carriers
Decreased renal tubular reabsorption of lysine, arginine, ornithineand cysteine may lead to what complciation?
Kidney stones
cystine kidney stones due to increased levels of cystine in the urine
What is typically produced in the rough endoplasmic reticulum?
Secretory, lysosomal and integral membrane PROTEINS
What is typically produced in the smooth endoplasmic reticulum?
Steroid and phospholipid synthesis
steroid producing cells in the adrenals, gonads and liver contain a well-developed smooth ER
Findings of weakness on foot plantarflexion, foot inversion, toe flexion and sensory loss over the sole of the foot are characteristic of what nerve injury?
Tibial nerve injury
may occur due to deep puncture injury at the level of the popliteal fossa or knee surgery
What is the mechanism of action of the drug anastrozole?
Aromatase inhibitor
(inhibits aromatization of androgens, inhibiting estrogen synthesis)
Used in treatment of ER-positive breast cancer in postmenopausal women
Integrin is transmembrane adhesion protein that interacts with elements within the cell and outside the cell to hold a cell in place. What molecules does integrin bind to within the cell and outside the cell?
Outside cell - fibronectin, collagen, laminin
Inside cell - keratin, actin
What drug is used to medically induce an asthmatic state in patients suspected of having asthma?
Methacholine
Methacholine is a muscarinic cholinergic agonist that induces bronchial smooth muscle contraction and bronchial mucus production
What kind of bacteria can be found in the soil and survive boiling temperatures (212F/100C)?
Spore-forming bacteria
Clostridium and Bacillus species
Where are two common locations for Burkitt lymphoma to appear?
Jaw lesion (endemic form in Africa)
Pelvis or abdomen in sporadic form
What is the most common type of glomerulonephritis and frequently appears 3-7 days after an upper respiratory infection?
IgA nephropathy (Berger disease)
Painless, episodic, self-limited hematuria is frequently seen within 5 days of an upper respiratory tract infection
mesangial IgA deposits can be seen on immunohistochemical staining
What is the venous drainage of internal and external hemorrhoids?
Internal (above pectinate) - superior rectal vein → inferior mesenteric vein → portal system
External (below pectinate) - inferior rectal vein → internal pudendal vein → internal iliac vein → common iliac vein → IVC
What symptoms are typically caused by temporal arteritis (giant cell vasculitis)H?
- Headache, typically in the temple region
- Jaw pain while chewing
- Polymyalgia rheumatica - neck, torso, pelvic pain
- Sudden vision loss
How many calories are yielded per gram of protein, carbohydrate and fat?
Protein - 4 Cal/g
Carbs - 4 Cal/g
Fat - 9 Cal/g
What cellular organelles oxidase very long chain fatty acids and phytanic acids (branched chain fatty acids)?
Peroxisomes
Mitochondria CANNOT oxidase the very long chain fatty acids
What are the key growth factors that stimulate angiogenesis?
Vascular endothelial growth factor (VEGF)
Fibroblast growth factor (FGF)
How is the A-a gradient calculated?
PAO2 - PaO2 = A-a gradient
PAO2 (O2 in alveoli) = 150 - ( PaCO2 / 0.8)
PaO2 (O2 in arteries) = arterial blood gas measure
What are the four morphologic stages of lobar pneumonia?
Congestion - red lobe, dilated alveoli, bacterial exudate
Red hepatization - red lobe, exudate contains RBCs, neutrophils, fibrin
Gray hepatization - pale, gray lobe, exudate only contains alveoli and fibrin
Resolution - restoration of normal lung architecture
What amino acid cannot be made and is thus essential in phenylketonuria?
Tyrosine
presents with intellectual disability, seizures, light pigmentation of skin/hair, and a musty odor
What causes pleuritic chest pain and low-grade fever 2-4 days following a transmural myocardial infarction?
Early-onset pericarditis can develop in 10-20% of people
This is caused by an inflammatory reaction to cardiac muscle necrosis that occurs in the adjacent visceral and parietal pericardium
(late-onset pericarditis weeks to months after MI is due to autoimmune-mediated Dressler syndrome)
Fracture of the femoral neck (common in elderly fall scenarios) may be complicated by osteonecrosis caused by injury to what artery?
Medial femoral circumflex artery
This artery provides the majority of the blood supply to the femoral neck and head
What pancreatic secretion is stimulated by secretin?
HCO3-
Secretin is released in response to increased H+ (gastric acid) in the duodenum
What two types of cancers are strongly associated with human papillomavirus and what types of HPV?
Cervical squamous cell carcinoma (women)
Anal squamous cell carcinoma (men, particularly w/ HIV)
HPV 16 and 18 are high risk strains
What extraintestinal manifestations occur in Crohn disease as a result of impaired absorption in the small intestines?
Macrocytic anemia → B12 and folate deficiency
Kidney stones → calcium loss in feces bound to fat (↑ oxalate absorption leading to stones)
Gallstones → decreased bile acid reabsorption in the terminal ileum
What vitamin supplementation can reduce cormorbidities in patients with measles (ocular complications, diarrhea and pneumonia)?
Vitamin A
Esp. reduces ocular complications of measles (remember Vitamin A is like the eye health vitamin)
What class of drug is glyburide and what is its mechanism of action?
Sulfonylurea
Sulfonylureas increase endogenous insulin secretion by binding to and closing the K+ channel in pancreatic beta cell membranes → causes cell depolarization → insulin release via ↑ Ca2+ influx
What is the name of the dopaminergic pathway that controls prolactin secretion?
Tuberoinfundibular pathway
(antipsychotic drugs can block dopamine in this pathway, resulting in increased prolactin secretion and subsequent galactorrhea)
What is the name of the dopaminergic pathway that regulates behavior?
Mesolimbic-mesocortical pathway
this is the pathway targeted for dopamine block by antipsychotic medications to treat schizophrenia
What is the name of the dopaminergic pathway that regulates coordination of voluntary movement?
Nigrostriatal pathway
reduced dopamine in this pathway is responsible for Parkinsonism
What is hibernating myocardium?
This refers to changes due to chronic myocardial ischemia due to reduced coronary blood flow (perhaps due to a stenosis)
It results in decreased contractility and left ventricular systolic dysfunction as the heart adapts to the lower oxygen delivery, attempting to self-preserve the myocardium
These changes are REVERSIBLE by improving the coronary blood flow (through surgical or other means)
Asplenic patients have increased susceptibility to what bacteria and what type of infection?
↑ susceptibility to encapsulated organisms such as Strep pneumoniae, N. meningitidis and H. influenzae
These infections result in bacteremia and sepsis because the spleen acts as a blood filter capable of removing circulating pathogens and stimulating opsonizing antibody synthesis
A patient presenting with frequent self-limited, colicky abdominal pain, facial swelling and lab workup indicating complement protein C1 excessively cleaving C2 and C4 likely has what disorder?
C1 inhibitor deficiency
(inhibitor deficiency meaning there is thus too much C1 around cleaving shit)
Buildup of bradykinin because of increased C1 cleaving activity causes the angioedema
Sucrose is a disaccharide composed of what two monosaccharides?
Sucrose = Fructose + Glucose
People with hereditary fructose intolerance (Aldolase B deficiency → toxic accumulation of fructose 1-phosphate) should avoid sucrose and fructose
What is the rate-limiting step in fatty acid synthesis?
Conversion of acetyl-CoA to malonyl-CoA via the enzyme Acetyl-CoA carboxylase (occurs in the cytoplasm)
What molecule inhibits mitochondrial carnitine acyltransferase (carnitine shuttle), thereby inhibiting beta-oxidation of fatty acids?
Malonyl-CoA
Because malonyl-CoA is used in the synthesis of fatty acids (indicating an anabolic state), its presence in high concentrations inhibits the breakdown of fatty acids (a catabolic function)
What is the major rate-limiting step in glycolysis?
Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate by phosphofructokinase-1
What is the function of the c-Myc oncogene?
c-Myc functions as a transcription activator controlling cell proliferation, differentiation and apoptosis
It is overactive in Burkitt lymphoma; t(8:14)
Myocardial infarction with ST elevations in leads II, III and aVF would indicate occlusion of which coronary artery?
Right coronary artery
II, III, aVF indicate an infarction on the inferior aspect of the heart
Myocardial infarction with ST elevations in leads V1-V4 would indicate occlusion of which coronary artery?
Left anterior descending
V1-V4 indicate infarction on the anteroseptal aspect of the heart
Myocardial infarction with ST elevations in leads V5 and V6 (and possibly I and aVL) would indicate occlusion of which coronary artery?
Left circumflex artery
V5-V6 indicate infarction on the lateral wall of the left ventricle
What is a lactose-fermenting, indole-positive gram-negative rod?
E. coli
Indole-positivity helps distinguish E. coli from Enterobacter cloacae, another gram-negative lactose-fermenting rods that commonly causes UTI
Where in the ear does hearing loss due to chronic exposure to loud noises occur?
Organ of corti → damage is specifically done to the stereociliated hair cells within the organ of corti
Compared to healthy individuals, people with cystic fibrosis will have high concentrations of what in their sweat?
Cholride and sodium
Normally, cholride is resorbed via CFTR with sodium following as isotonic eccrine sweat moves through the eccrine ducts to the skin surface (making hypotonic sweat)
→ this resorption doesn’t occur in CF patients due to absent CFTR and so cholride and sodium are lost in the sweat
What muscle travels through the greater sciatic foramen? lesser sciatic foramen?
Piriformis m. travels through greater sciatic foramen (along with the sciatic nerve)
Obturator internus m. travels through the lesser sciatic foramen
What component of gram-negative bacteria (such as E. coli) is responsible for causing septic shock?
Lipid A, a component of lipopolysaccharide (LPS) in gram-negative bacterial cell walls
LPS (and thus Lipid A) is released from bacterial cells during division or bacteriolysis
Lipid A causes activation of macrophages leading to release of IL-1 and TNF-a which primarily cause the signs/symptoms of septic shock
What is peripheral venous capacitance?
The amount of blood volume that can be held in the peripheral veins at a given point in time
Venodilators (nitrates) would thus increase peripheral venous capacitance by widening the vessels, allow for greater volume
Vasoconstrictors would decrease venous capacitance
What are possible paraneoplastic syndromes of small cell carcinoma?
ACTH secretion by tumor (causing Cushing syndrome)
ADH secretion by tumor (causing SIADH)
Eaton-Lambert syndrome (blocks ACh release at NMJ)
What are possible paraneoplastic syndromes of squamous cell carcinoma?
PTHrP secretion by tumor (causing hyperparathyroidism-like symptoms → ↑ serum Ca2+, bone pain etc.)
What is the most common malignant neoplasm of the liver?
Metastasis from another primary source (breast, lung, colon)
Metastatic cancer in the liver typically appears as multiple nodules throughout the liver
Pelvic floor weakening resulting in stress urinary incontinence is caused by weakening/injury of what muscle?
Levator ani muscle
Kegel exercises are pelvic floor strengthening exercises which may treat or improve stress urinary incontinence
By what mechanism do the two different agents lactulose and rifaximin treat hepatic encephalopathy?
Hepatic encephalopathy is caused by accumulation of ammonia in the brain
Lactulose → increases conversion of ammonia to non-toxic ammonium (NH4+ can’t be absorbed)
Rifaximin → decreases intraluminal ammonia production by antibiotic action, altering GI flora
What cardiac abnormality is associated with DiGeorge syndrome (trisomy 18)?
Tetralogy of Fallot
What cardiac abnormality is associated with Friedreich’s ataxia (GAA trinucelotide repeat on frataxin gene)?
Hypertrophic cardiomyopathy
What cardiac abnormality is associated with tuberous sclerosis?
Valvular obstruction due to cardiac rhabdomyomas
What cardiac abnormality is associated with Down syndrome?
Atrial septal defects (endocardial cushion defects)
A 40 y/o woman presents with a 6-month history of episodic bouts of ‘spinning sensation” associated with nausea, ringing and difficulty hearing in her left ear. Between these episodes, she doesn’t experience any of these symptoms. Disease/Dx?
Meniere disease - a disorder of the inner ear
Caused by increased volume and pressure of endolymph in the inner ear
Causes recurrent, episodic vertigo (dizziness), ear pain and hearing loss/tinnitus
What type of kidney injury is most commonly caused by chronic use of NSAIDs?
Chronic interstitial nephritis
This causes fibrosis, tubular atrophy and can lead to papillary necrosis and scarring
What tumors are associated with familial retinoblastoma?
Retinoblastoma (ocular neoplasm, duh)
Osteosarcoma (bone tumor of the metaphysis)
What is the mechanism of action of the drugs amiloride and triamterene?
Block the epithelial sodium channel (ENaC) in the collecting duct of the renal tubules, inhibiting sodium reabsorption
These are K+ sparing diuretics and can cause hyperkalemia
A 23 yo male presents with weakness and gait disturbance. He indicates he has difficulty releasing doorknobs after use. Physical exam shows cataracts, frontal baldness and gonadal atrophy. Disease/Dx?
Myotonic dystrophy
Autosomal dominant trinucleotide (CTG) repeat disease of the DMPK gene
Causes abnormal expression of myotonin protein kinase
A deep, bleeding ulcer on the posterior wall of the duodenal bulb has likely penetrated which artery?
Gastroduodenal artery
The gastroduodenal artery perfuses both the pylorus of the stomach and the proximal part of the duodenum
(the duodenal bulb is the very first part of the duodenum that the stomach empties into)
What is coronary steal?
A phenomenon in coronary vessels in which blood flow to ischemic areas is reduced due to arteriolar vasodilation in nonischemic areas
Drugs such as adenosine and dipyridamole can cause coronary steal due to their selective vasodilatation of coronary vessels
What is the role of the NF-kB pathway in the immune system?
NF-kB is a proinflammatory transcription factor that increases cytokine production
What is a common adverse effect of the cancer drug vincristine?
Neurotoxicity - commonly manifests as peripheral neuropathy
Vincristine (vinca alkaloid) inhibits microtubule formation, preventing cell division (in M phase of cell cycle)
What three drugs most commonly cause drug-induced lupus erythematosus?
Hydralazine (arteriolar vasodilator)
Procainamide (class Ia antiarrhythmic)
Isoniazid
Typically occurs in people who are “slow acetylators”
Anti-histone and anti-nuclear antibodies may be seen on labs
A patient’s ECG shows absent P waves, irregularly irregular R-R intervals and narrow QRS complexes. What cardiac abnormality is present?
Atrial fibrillation
Caused by heightened atrial excitability, AV nodal refractory period prevents a corresponding ventricular arrhythmia
A 27 y/o woman presents with a 1-day history of rash that began approximately 2 weeks after an episode of recurrent, painful genital lesions. The rash appears as many red, round papules with some evolving into target lesions. Disease/Dx?
Erythema multiforme
Cell-mediated inflammatory disorder of the skin commonly associated with HERPES SIMPLEX VIRUS
What distinguishing lab findings would help differentiate von Willebrand disease from immune thrombocytopenic purpura?
Platelet count would be NORMAL in von Willebrand disease (it is a qualitative disorder, also ↓ aPTT)
Platelet count would be DECREASED in thrombocytopenic purpura because of autoimmune destruction of platelets
Both would present with recurrent nosebleeds (epistaxis), easy bruising, petechiae and mucosal bleeding
What is the suspected origin of small cell carcinoma?
Neuroendocrine origin
This is why small cell carcinoma typically stains for neuroendocrine markers such as CHROMOGRANIN, neural cell adhesion molecules and enolase
May also tie in to its ADH/ACTH secretion and Lambert-Eaton syndrome
Where doe the patellar ligament attach to the lower leg?
Tibial tuberosity
Quadriceps muscle group attaches to the patella and the patella attaches to the tibial tuberosity → this allows for leg extension at the knee
What are common adverse effects of dihydropyridine calcium channel blockers (amlodipine, nifedipine)?
Dizziness or lightheadedness
PERIPHERAL EDEMA
What cytokine mediates cachexia (anorexia, malaise, weight loss, generalized wasting) in patients with cancer?
TNF-alpha
TNF-a is thought to mediate paraneoplastic cachexia by suppressing appetite and increasing basal metabolic rate
What hormone does high levels of prolactin suppress?
GnRH → this leads to ↓ LH/FSH and ↓ estrogen/testosterone
What type of cellular injury is seen in reperfusion injury?
Reperfusion injury occurs after blood flow is resumed in tissue recovering from ischemic damage
It causes cellular damage by oxygen free radical generation, mitochondrial damage and inflammation
What are the acute effects of corticosteroid use on white blood cell count?
↑ neutrophil count (temporarily, due to ‘demargination’of neutrophils previously attached to vessel walls)
↓ basophils, eosinophils, monocyte/macrophage, lymphocytes
What causes the accumulation of lipid cells in alcohol-induced hepatic steatosis?
Decreased free fatty acid oxidation (↓ fatty acid breakdown)
Thought to occur due to excess NADH production by the two major alcohol metabolism enzymes; alcohol dehydrogenase and aldehyde dehydrogenase
What are the two most common causes of acute respiratory distress syndrome (ARDS)?
Sepsis and pneumonia
In both scenarios, cytokines circulating in response to infection ultimately cause leakage of protein and fluid into the alveolar space
What main structures are compressed by a transtentorial (uncal) herniation?
Oculomotor nerve (CN III) and sometimes posterior cerebral artery (causing vision disturbance)
What main structures are compressed by a subfalcine herniation?
Anterior cerebral artery (causing infarction)
What main structures are compressed by a tonsillar herniation?
Medulla/brainstem (causing cardiopulmonary arrest)
Selective COX-2 inhibitors (celecoxib) have a different side effect profile than NSAIDs and asipirin. What adverse effects are blunted/absent with selective COX-2 inhibitor use?
Lower risk of bleeding and gastric ulceration
The lower risk of bleeding results from inhibition of prostacyclin (PGI2) inhibition of platelet aggregation which can actually INCREASE risk of cardiovascular events (↑ platelet aggregation)
A patient presents with signs and symptoms of chronic hemolytic anemia. Their red blood cells demonstrate increased fragility in an acidified glycerol lysis test. Disease/Dx?
Hereditary spherocytosis
(spectrin/ankyrin mutations causing red cell cytoskeleton abnormalities)
A positive acidified glycerol lysis test is diagnostic for hereditary spherocytosis
→ increased osmotic fragility is due to decreased surface area to volume ratio
