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USMLE Wrong Answer Facts > UWorld QBank - 2nd round - part 4 > Flashcards

UWorld QBank - 2nd round - part 4 Flashcards

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USMLE® Step 1 flashcards
1
Q

What would you see on biopsy with a thyroid papillary carcinoma?

A
  • Large cells w/ overlapping nuclei containing finely dispersed chromatin -> ground glass appearance (orphan annie eyes)
  • Numerous intranuclear inclusions and grooves
  • Psammoma bodies
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2
Q

Which reaction in the TCA requires thiamine?

A

alpha ketoglutarate -> succinyl CoA which uses alpha-ketoglutarate dehydrogenase complex

(Note: pyruvate dehydrogenase also requires, but this is not part of TCA, b/c it forms acetyl CoA which then combines w/ OAA -> citrate)

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3
Q

How is aortic regurgitation murmur best heard?

A

Early diastolic, high-pitched blowing decrescendo murmur, best heard at L sternal border, w/ patient leaning forward (brings valve closer to chest wall) and at end expiration (most left sided heart sounds heard better at end expiration)

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4
Q

How would the cardiac cath blood pressure curve appear for someone w/ aortic regurgitation?

A

High peaking LV and aortic pressures during systole (because increased blood volume in LV) and a steep diastolic decline of aortic pressure (because regurgitation)

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5
Q

How is Isoniazid metabolized? What would cause high levels of Isoniazid for a longer period of time?

A

acetylation in hepatic microsomal system by enzyme n-acetyl transferase -> excreted in urine

Slow acetylators of isonaizid will take longer to metabolize.

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6
Q

A young patient presents w/ recurrent bouts of acute pancreatitis. HIs ultrasound is normal, he has no other known medical problems, takes no medication, and does not consume alcohol. What is most likely the cause? What is usually the major cause for this?

A

Hypertriglyceridemia -> excess free fatty acids cannot all be bound up by albumin -> direct injury to pancreatic acinar cells

Usually gallstones and alcoholism are the main causes but if these and structural, genetic abnormalities are ruled out one should consider hypertrigs.

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7
Q

What would you see on biopsy in medullary carcinoma of the thyroid?

A

Nests of uniform polygonal or spindle shaped cells w/ extracellular amyloid deposits which stain positively for congo red -> originate from parafollicular calcitonin secreting C-Cells

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8
Q

What is the appearance of follicular adenoma/carcinoma of the thyroid on biopsy?

A

FA: Sheets of uniform cells forming colloid containing microfollicles

FC: would have similar findings (and even more closely resembling thryoid tissue) w/ capsular and vascular invasion

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9
Q

Why are patients w/ ataxia-telangiectasia predisposed to infections?

A

IgA deficiency predisposes to frequent infections of upper and lower airways

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10
Q

How would a patient w/ pantothenic acid deficiency present?

A

Rare condition of low Coenzyme A -> usually in severely malnourished -> paresthesias, dysesthesias (burning feet syndrome), and GI distress

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11
Q

What happens to someone who is deficient in CD55 and CD59? What is this disorder associated with?

A

Paroxysmal Nocturnal Hemoglobinuria (PNH) -> complement mediated hemolysis from a deficiency in synthesis of glycosylphosphatidylinositol (GPI) anchor necessary for attachment of CD55 (decay accelerating factor) and CD59 (MAC inhibitory protein) - both of these protect from complement attack.

Often associated w/ budd chiari syndrome, pancytopenia and aplastic anemia

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12
Q

What drugs are likely to cause drug induced lupus? How are they metabolized?

A

Hydralazine and Procainamide -> metabolized by acetylation in liver then renal excretion -> slow acetylators may be more prone to develop lupus like effects (Dapsone and Isoniazid are also metabolized by acetylation)

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13
Q

What is the MoA of dobutamine?

A

beta-agonist -> mainly on B1 w/ some activity on B2 and A1

B1 stimulation -> increased cAMP -> positive ionotrope effect (increased contractility) & weakly positive chronotrope (increased heart rate) & increased cardiac conduction velocities

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14
Q

Which factors can predispose patients to first dose hypotension w/ ACEI therapy? Which drugs should be watched out for?

A

Hyponatremia, hypovolemia (secondary to diuretic therapy), low baseline blood pressure, high renin/aldosterone, renal impairment, and heart failure.

Thiazide/Loop diuretics can cause hypoNa+ and hypH2O

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15
Q

What is another term for precision?

A

Reliability

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16
Q

What secondary cell signaling molecule is responsible for activating Raf kinase in a growth factor messenger pathway that includes Tyrosine kinase and SOS protein and MAP kinase downstream?

A

GTP as part of the Ras (G-Protein) system in the Ras-MAP Kinase signaling pathway

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17
Q

What opportunistic infections should be looked out for in HIV+ patients w/ CD4 counts

A

Mycobacterium avium complex (M avium & M intracellulare) - grows at 41 C

Prophylaxis w/ Azithromycin b/c it is resistant to most typical antibacterial drugs

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18
Q

Which symptoms of opioid use are usually not affected by increased tolerance to the drug?

A

Constipation (because this is a result of direct stimulation of Mu-R in the GI tract by opioid) and Miosis (b/c this caused by opioid activation of PANS innervation on the pupil)

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19
Q

How quickly will loss of myocardial contractility occur upon total myocardial ischemia during a heart attack? When will irreversible injury occur?

A

Loss of ATP and build up of toxins in the highly metabolically active regions will result in loss of contraction w/in 60 seconds of ischemia (affected portion of cardiac wall will stop contracting completely)

After 30 minutes of ischemia there will be irreversible injury to the myocardium (before this time point there is enough adenosine present to keep it going upon reperfusion)

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20
Q

What is the MoA of etanercept?

A

Causes TNF-alpha inhibition by linking soluble TNF-a receptor to the Fc component of IgG -> hence it is a soluble receptor decoy protein

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21
Q

How can you distinguish the activity of pharmaceutical biological agents by the suffixes used? What about the substems

A
  • mab = monoclonal antibody
  • cept = receptor molecule
  • nib = kinase inhibitor

Substems are also used to identify drug targets (e.g. c = CV, f = fungal, tu = tumor) and origin of the antibody (e.g. o = mouse, u = human, xi = chimeric, zu = humanized)

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22
Q

How likely is chronic infection of HBV in adults vs. peds?

A 
Adults = 10% become chronic
Peds = 90% become chronic
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23
Q

What is the most specific marker for diagnosis of acute HBV infection?

A

IgM anti-HBc - because it is present in the window period when HBsAg has been cleared and anti-HBs not yet detectable

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24
Q

What is the MoA of Fenoldopam?

A

Selective Dopamine-1 receptor agonist (no effect on alpha/beta-Rs) -> activates adenlyl cyclase -> increased cAMP -> vasodilation of most arterial beds w/ emphasis on renal, coronary and mesentary -> significant reduction in systemic vascular resistance

This will drop BP and also lead to improved RBF and increased Na+ and H2O excretion -> good for managing short term severe HTN and all HTN emergencies

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25
Q

What do optic neuritis followed several months later by intention tremor, in a 30 year old female indicate?

A

Multiple Sclerosis

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26
Q

What is CD31 a marker for?

A

PECAM1 - an endothelial cell surface protein -> can be a marker for maligannt vascular neoplasms (e.g. angiosarcma)

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27
Q

Which hormone has the greatest effect on fetal lung surfactant production?

A

Cortisol (secreted from both fetal and maternal origin)

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28
Q

What are the key presenting signs of adenocarcinoma of the head of the pancreas? What are the main risk factors for this cancer?

A

Palpable but non-tender gallbladder (Courvoisier sign), weight loss, and obstructive jaundice (pruritis, dark urine and pale stools) from compression of the bile duct.

  1. Age (65-75 y.o), 2. Smoking, 3. Diabetes, 4. Chronic pancreatitis, 5. Genetic (e.g. MEN, HNPCC, FAPS)
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29
Q

What does a low fiber diet increase the risk for?

A

Colon cancer

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30
Q

A patient w/ long standing COPD is put on nasal cannula O2 supplementation, what is at high risk of occurring here and why?

A

Reduced respiratory rate b/c of a sudden decrease in stimulation of the Carotid bodies (these are main receptors that detect low O2 and increase respiratory rate -> if O2 is supplemented too much too quickly in a dependent patient as w/ COPD -> resp depression may occur) - Response to PaCO2 is blunted in patients w/ COPD

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31
Q

What reaction leads to a rash following contact with poison ivy/oak?

A

Urushiol from plants enters the skin and gets presented to T-cells in lymph node by APCs -> initiates CD8+ T-cell response -> release of inflammatory mediators and cell cytotoxicity -> keratinocyte apoptosis and pruritic rash

This is a TYPE IV HYPERSENSITIVITY RXN -> contact dermatitis

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32
Q

What are the features of lepromatous leprosy?

A

More severe form -> Widespread disease = plaques all over containing acid-fast bacilli in Macrophages and a TH2 cytokine profile (IL 4, IL 5, IL 10)

Lepromin skin test is negative (no skin rxn and nodule formation) b/c of a weak Th1 cell mediated immune response (unlike tuberculoid leprosy, which has strong Th1 response)

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33
Q

What hormone and gonadotropin levels are found in Klinefelter’s syndrome?

A
  • Sertoli cell destruction -> decreased inhibin B -> increased FSH
  • Leydig cell dysfxn -> decreased testosterone -> increased LH
  • Gonadotropin excess -> increased aromatase activity -> high estrogen
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34
Q

What is the nucleic acid life cycle of HBV?

A

Partially double stranded DNA enters nucleus -> repaired into ds-DNA -> transcription into +RNA -> translation of viral proteins and REVERSE transcription into ss-DNA -> forms double stranded DNA progeny

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35
Q

What is the most important factor for determining peak bone mass in individuals?

A

Genetic Factors (Caucasians have lower bone densities than Africans)

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36
Q

What are the presenting signs for SVC syndrome and what is the cause?

A

1 = lung cancer followed by non-Hodgkin lymphoma

Caused by anterior mediastinal mass blocking the superior vena cava -> Facial edema and plethora (“Puffy face”), Dilated vessels over neck and upper trunk , Cerebral edema from increased back pressure (headache, dizzy, confused)

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37
Q

What can frequently follow an URI, especially in elderly?

A

Pneumonia by S. pneumo, S. aureus and H. Flu

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38
Q

What is true of the rate of blood flow in pulmonary capillary circulation vs. systemic circulation?

A

In normal healthy person blood flow rate should always be same whether exercising or at rest (if not it could cause either decrease filling or overload of LV)

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39
Q

What are 3 main risks of Amphoterecin B treatment?

A

Renal tox -> hypokalemia, hypoMg2+ and low Epo (could cause normocytic normochromic anemia) -> supplement patients w/ K+ and Mg while undergoing treatment

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40
Q

What is marantic endocarditis?

A

Non-bacterial thrombotic endocarditis from a hypercoaguable state in cancer patients

Note: similar to migratory thrombophlebitis in cancer patients (Trousseau syndrome)

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41
Q

Is it ethical to treat/prescribe medications for friend’s and family?

A

Only during emergency situations when no other physicians are available

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42
Q

What action would cause damage to the lower trunk of the brachial plexus and what would the symptoms be?

A

Sudden upward jerking of the arm at the shoulder -> hand clumsiness/paralysis from damage to CN8-T1 nerve roots which form median and ulnar nerves and innervate all intrinsic muscles of the hand

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43
Q

What irreversible changes may result from an ASD?

A

Increased right heart pressure -> Laminated medial hypertrophy of pulmonary arteries in response -> Irreversible pulmonary vascular sclerosis (right ventricle can longer tolerate closure of ASD at this point)

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44
Q

Are right ventricular hypertrophy and right atrial enlargement reversible in the setting of pulmonary HTN?

A

Yes, if pulm HTN is fixed, right heart will revert back to original morphology

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45
Q

What is the easiest way of calculating the probability of getting at least one negative result?

A

Calculate the probability of getting all positive results and subtract from 1

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46
Q

What are penicillins structural analogs of?

A

D-ala-D-ala (component of peptidoglycan cell wall) -> this is how they are able to bind transpeptidases and inhibit cell wall synthesis (N-acetylmuramic acid and N-acetylglucosamine are precursors to cell wall components)

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47
Q

Which area is affected in acute drug induced nephritis and what leads to the damage caused by this? Symptoms?

A

Acute interstitial nephritis (AIN) - damage to interstitium mainly, and possible tubular involvement (glomeruli and papillae are spared)
-Caused by NSAIDs (months after), sulfonamides, rifampin, diuretics, PPIs, and beta lactam antibiotics (1-2weeks after) -> induce IgE hypersensitivity rxn
Sx = fever, maculopapular rash, and acute renal failure

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48
Q

What conditions lead to renal papillary necrosis?

A

SAAD papa w/ papillary necrosis -

Sickle cell disease, Analgesic nephropathy, Acute severe pyelonephritis, Diabetes

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49
Q

How do you treat acute arsenic poisoning?

A

Chelating agents -> Dimercaprol (displaces arsenic ions from sulfahydryl groups of enzymes) -> watch out for nephrotox and HTN from dimercaprol which has narrow therapeutic range

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50
Q

What is methylene blue indicated for?

A

Tx of methemoglobinemia (converts Fe3+ to Fe2+)

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51
Q

What is the most common type of lung cancer in the US and how does it present?

A
  • Adenocarcinoma in situ (bronchioalveolar carcinoma - malignant) -> tumor of alveolar epithelium at periphery of lung
  • Biopsy = growth along intact alveolar septa (no invasion of vessels/stroma) & well differentiated dysplastic columnar cells (w/ or w/o intracellular mucin)
  • Sx = cough, SOB, hemoptysis & copious amounts of pale/tan colored watery fluid (bronchorrhea)
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52
Q

What are benign neoplasms of the lung?

A

hamartomas

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53
Q

What is responsible for the green color that can appear in pus or sputum during bacterial infection? What is this molecules fxn?

A

Myeloperoxidase -> a blue-green heme based pigmented molecule w/in azurophillic granules of PMNs -> catalyze HOCl formation from peroxide

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54
Q

What effect would hemolysis or RBC extravasation have on sputum during infection (e.g. in pneumococcal pneumonia)?

A

Rusty colored sputum

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55
Q

What is the translocation and gene overexpression in Burkitt’s lymphoma?

A

t(8;14) -> overexpression of C-MYC (controller of cell proliferation)

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56
Q

What are the main side effects of metformin?

A

GI upset and lactic acidosis

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57
Q

What may result from elevated levels of methylmalonic acid?

A

Myelin synthesis abnormalities -> neuro damage (assoc. w/ V. B12 def)

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58
Q

What is the main hemodynamic adaptation that sustains CO in aortic regurgitation?

A

Increased LV end diastolic volume via increased preload -> this will sustain forward LV stroke volume to remain adequate (but still reduced from normal)

59
Q

The levels of what will decrease in the stool upon lactose consumption by someone who has lactase deficiency? What will increase?

A

Stool pH will DECREASE (because undigested lactose accumulates -> osmotic diarrhea and bacterial fermentation of lactose -> short chain fatty acids and excess hydrogen ions)

Stool osmotic gap will INCREASE (because poorly absorbable substances are present, i.e. lactose)

60
Q

How can you differentiate dermatitis herpetiformis from atopic dermatitis (eczema)?

A

DH = Commonly in 4th and 5th decades of life (uncommon in children), clusters of pruritic vesicles and plaques on butt and extensor surfaces, associated w/ celiac disease

AD = Common in peds and decreases w/ age, red weeping/crusted lesions on face, trunk and extensors that recur often, intense PRURITIS, and high IgE/eosinophilia, associated w/ atopic diseases, allergic rhinitis, ASTHMA (allergic triad)

61
Q

Which areas of the body can Kaposi Sarcoma present on and is the appearance and biopsy findings of this lesion?

A

Characteristic skin involvement but can also spread to lungs and GI tract
-Vary from reddish/violet flat maculopapular lesions to raised hemorrhagic nodules or polyploid masses
Biopsy = Spindle cells w/ cytologic atypia, blood vessel proliferation, and extravasated RBCs w/ hemosiderin deposits

62
Q

What Mitochondrial features are associated w/ irreversible cell damage?

A

Vacuoles and phospholipid-containing amorphous densities in MT

63
Q

What are nucleus features associated w/ reversible cell damage?

A

Disaggregation of nuclear granules and clumping of nuclear chromatin

64
Q

What is adenomyosis?

A

Presence of endometrial glandular tissue w/in the myometrium -> menorrhagia and dysmenorrhea and uniformly enlarged uterus (from uterine smooth muscle hypertrophy)

65
Q

What is the principle characteristic of endometriosis?

A

Location of endometrial tissue at any location OUTSIDE of the uterus (differentiate from adenomyosis which is in uterus muscle wall)

66
Q

Which factors utilize the Tyrosine kinase associated receptor + JAK/STAT signaling pathway? TK w/ intrinsic enzyme activity + MAP kinase?

A

JAK/STAT = receptors for cytokines, Growth Hormone, prolactin, IL2

MAP kinase = growth factor receptors: EGF, PDGF, FGF

67
Q

Which cells increase in the blood cell count following glucocorticoid therapy and why?

A

PMNs because of demargination from vessel wall

68
Q

What diseases are associated with over expression of n-MYC?

A

Neuroblastoma and small cell carcinoma of the lung

69
Q

How does inoculation w/ inactivated influenza vaccine provide immunity? How does this differ from live attenuated vaccines?

A

Inducing neutralizing antibodies against hemagglutinin antigen -> inhibition of viral entry into cells

LAVs enter cells and strongly stimulate MHC class I antigen processing pathway -> CD8+ cytotoxic T-cell response upon infection (killed vaccines don’t enter cell)

70
Q

What is the most common cause of lung abscess?

A

Aspiration oropharyngeal contents (often including anaerobic bacteria) -> aspiration pneumonia -> foul smelling sputum production (abscess usually in right lung)

71
Q

What usually results from aspiration of gastric contents?

A

Chemical pneumonitis from gastric contents (lung abscess less likely, but possible if admixed w/ oropharyngeal contents)

72
Q

What would be affected from penetrating injury above the clavicle between the sternum and midclavicular line?

A

Puncture of pleura -> pneumothorax, tension pneumothorax, or hemothorax can occur

73
Q

Where is the ansa cervicalis located?

A

in the neck above the cricothyroid cartilage

74
Q

What factor is most important and useful in a test used for screening?

A

Screening: high sensitivity test w/ a negative result helps RULE OUT a diagnosis -> SNOUT (e.g. newborn screening for PKU)

75
Q

What is the utility of tests with high specificity?

A

highly likely to identify those without a disease -> highly specific tests have a low rate of false positives => therefore w/ a positive test result specificity is good for RULING IN a disease -> SPIN

76
Q

What system exacerbates the symptoms of CHF in an effort to improve the disease state?

A

Decreased CO -> increased sympathetic output, and low blood pressure to JGA -> activation of rening-angiotension-aldosterone pathway -> release of ADH and vasoconstrction

Will improve CO but excessive vasoconstriction will worsen and system will cause peripheral edema and pulmonary congestion

77
Q

What would you see on hepatic biopsy in a patient with HBV infection?

A

Acute hepatitis -> ballooning degeneration, hepatocyte necrosis, and portal inflammation

HBV -> Cytoplasm filled with spheres and tubules of HBsAg -> finely granular eosinophilic “ground-glass” appearance in cytoplasm

78
Q

What would you see on hepatic biopsy in patients w/ HCV infection?

A

lymphoid aggregates in portal tracts and focal areas of macrovesicular steatosis

79
Q

What occurs to GFR, RPF and FF in a patient who is very hypovolemic?

A

-Low blood volumes results in very low RPF and this is worsened by peripheral vasoconstriction (from ReninAT system)
-GFR is also low because of this, but efferent arteriole constriction by ATII results in a less pronounced decrease of GFR
==> therefore GFR will be low, RPF very low and FF high

80
Q

What are the effects of NE on adrenergic receptors?

A
  1. alpha 1 agonism => increased IP3 (and DAG and Ca) in peripheral smooth muscle cells -> vasoconstriction
  2. alpha 2 agonism => decrease cAMP -> decrease NE and insulin release
  3. beta 1 agonism => increased cAMP in cardiac myocytes -> increased contractility
  4. beta 2 agonism => increased cAMP -> broncho and vasodilation (but the effect on B2 is very minimal w/ NE)
81
Q

What is Xanthelasma?

A

A type of xanthoma that forms around the eyelids during conditions with hypercholesterolemia (e.g. high LDL or biliary stasis)

82
Q

A patient presents w/ testicular mass and increased serum T3/T4, what is the most likely cause?

A

Non-seminoma Germ cell tumor that is secreting beta-hCG (which has the same alpha subunit as TSH, LH and FSH, and similar beta subunit as TSH) -> similarity to TSH results in paraneoplastic hyperthyroidisim

83
Q

What type of patients are at highest risk for drug induced lupus?

A

Slow acetylators on Hydralazine, Procainamide, Isoniazid

84
Q

What would you find on histology of granulosa cell tumor?

A

Call-Exner bodies -> small follicle-like structures filled w/ eosinophilic secretions

85
Q

What are the characteristics of neuroblastoma?

A

Neuroblastoma = Small blue round cell tumor from adrenal medulla; catecholamines in urine; N-myc amplification; retroperitoneal mass that can displace kidney and cross midline; Sx = spontaneous bursts of eye movements, hypotonia and myoclonus (dancing feet and eyes)

86
Q

What are the characteristics of Wilm’s tumor?

A

Nephroblastoma (tumor of peds 2-4 y/o) -> palpable unilateral flank mass; biopsy shows primitive metanephric tissue (embryonic origin); Loss of fxn mutation of WT1 or WT2 (chromosome 11, tumor suppressor genes)
-Beckwith-Wiedemann syndrome (tumor, macroglossia, organomegaly)
WAGR complex (Wilms tumor, Aniridia, GU malformation, Retardation)

87
Q

What is the MoA of clopidogrel and ticlopidine and side effects?

A
  • ADP antagonists that inhibit platelet aggregation by preventing GPIIb/IIIa receptors from reaching surface of platelets
  • TTP may be seen but Main SE is seen w/ Ticlopidine -> may cause severe neutropenia -> present w/ fever and mouth ulcers (check CBCs frequently)
88
Q

What drugs can increase risk of hip fractures in elderly?

A

Anticonvulsants that induce CYP450 (increased vit. D catabolism), Drugs that decrease estrogen (aromatase inhibitors, medroxyprogesterone, GnRH agonists), PPIs (decreased calcium absorption), drugs that decrease bone formation (GLUCOCORTICOIDS, heparins, Thiazolidinediones)

89
Q

What type of drug is chlorthalidone?

A

Thiazide diuretic

90
Q

What actions increase heart sounds heard by hypertrophic cardiomyopathy? Decrease sound?

A

increased = decreased preload (abrupt standing, valsalva strain, Nitrolgycerin)

decreased = increased afterload/preload (Hand grip, squatting, passive leg raise)

91
Q

What replication defect most often leads to turner syndrome?

A

Paternal meiotic nondisjunction

92
Q

Injection of the buttocks at which location could cause superior gluteal nerve damage?

A

Superomedial quadrant (Superolateral quadrant is safest place to inject)

93
Q

What lab findings are most indicative of a poor prognosis for alcoholic cirrhosis?

A

Indicators of decreased liver function: Prolonged prothrombin time, hypoalbuminemia, and elevated bilirubin

94
Q

Which lab findings are indicators of livery injury?

A

Elevated AST, ALT, Alk Phos, and GGT (these do not provide info on liver fxn)

95
Q

What is hyponatremia and a lung mass indicative of ? What other findings would be seen?

A

SIADH from paraneoplastic syndrome of small cell lung carcinoma -> excess ADH causes transient hypervolemia -> hyponatremia, depressed plasma osmolality (more dilute), and elevated urine osmolality (less dilute)

96
Q

What mediates the side effects of niacin?

A

Excess prostaglandin -> skin flushing and warmth -> pretreatment w/ aspirin (in early stages of treatment) can reduce these SEs by blocking prostaglandin synthesis

97
Q

What is substance P? How can you decrease these levels?

A

11 amino acid polypeptide -> pain neurotransmitter in PNS and CNS

Capsaicin reduces pain by decreasing substance P in PNS

98
Q

How can you differentiate the myeloid cells in CML blood smear vs. AML?

A

CML cells are mature (multi lobed nuclei evident)

AML has immature looking cells (large nuclei) and auer rods

99
Q

What are the features of aplastic anemia? Bone marrow biopsy?

A

Pancytopenia -> low Hb, platelets and WBCs -> easy bruising w/ no LADopathy or HSMegaly

Bone marrow -> “Dry Tap” Devoid of hematopoietic elements -> replaced w/ fat cells, fibrous stroma, and scatter clusters of lymphocytes and plasma cells

100
Q

How can you differentiate aplastic anemia from myelofibrosis or hairy cell leukemia?

A

Myelofibrosis -> bone marrow replaced by fibrosis (extensive collagen deposition) and massive splenomegaly (to compensate for loss of bone marrow w/ extramedullary hematopoiesis)

HCL -> Patients generally present w/ pancytopenia and splenomegaly and characteristic “hairy cells” would be apparent (also +TRAP test, but still dry tap)

101
Q

What is the MoA of canagliflozin and dapagliflozin?

A

SGLT2 inhibitor -> which leads to urinary glucose loss -> as such it should be avoided in patients w/ moderate/severe renal impairment

102
Q

What type of drug is diphenoxylate? What effects can it have at certain doses?

A

Opiate anti-diarrheal (structurally similar to mepiridine) -> decreases GI motility

High doses will cause euphoria (like morphine) -> give w/ atropine to prevent dependance

103
Q

What are characteristic signs of typhoid fever?

A

Bacteremia from salmonella typhi -> fever, diarrhea that can become bloody, faint red maculopapular rash of chest/abdomen, hepatosplenomegaly

Severe cases -> transmural necrosis -> bowel perforation

104
Q

What is the histological finding in respiratory effects that can develop from acute pancreatitis?

A

AP can lead to ARDS -> Alveolar hyaline membranes would develop from diffuse injury to pulmonary (consists of fibrin exudate and plasma protein rich edema fluid mixed w/ cytoplasmic contents of damaged cells)

105
Q

What is the major manifestation of chylomicronemia (Type 1 familial hyperlipoproteinemia)?

A

Can lead to acute pancreatitis (note hyper trigs is a major cause of AP!!!) and eruptive skin xanthomas (tendon xanthoma and xanthelasma occur w/ high LDL)

106
Q

Which anatomical locations consist of transitional epithelium?

A

Urothelium -> urinary bladder, urethera, ureters, and gland ducts of the prostate

107
Q

What is the function of Interferon alpha and beta?

A

decrease protein synthesis in virally infected cells (host and viral mRNA ALL get degraded)

108
Q

Bilateral ovarian masses were removed from a 55 year old woman,containing poorly differentiated cells heavily loaded w/ mucous. The ovaries are secondary involved, where is the location of the primary tumor site?

A

Krukenberg tumor - one of the most common metastatic ovarian neoplasms -> from metastasized Gastric carcinoma (signet ring cell)
(breast pancreas and gallbladder also metastasize)

109
Q

What are the 3 mechanisms of metastasis of gastric carcinoma?

A
  1. Virchow Node - left supraclavicular node involvement
  2. Krukenberg tumor - bilateral metastasis to ovaries -> abundant mucin-secreting signet ring cells
  3. Sister Mary Joseph nodule - subcutaneous periumbilical metastases
110
Q

What findings are associated w/ Vit. A deficiency?

A

Eye problems (night/complete blind, spots on eyes, corneal perforation, keratomalacia), nonspecific derm abnormalities, humoral/cell-mediated immune system inhibition via damage to phagocytes and T-cells

111
Q

What intervention can be very useful in children w/ measles and in areas w/ high measles mortality rate?

A

Vitamin A supplementation

112
Q

What should be measured periodically in patients on long-term Lithium therapy?

A

TSH levels as Hypothyroidism is a major side effect and renal function (BUN/Cr). Also look out for nephrogenic diabetes and not for use during pregnancy

113
Q

What type of drug is citalopram?

A

SSRI

114
Q

What ion movement plays a role in causing cadiac myocytes to swell up during transient ischemia?

A

Na+/K+ exchanger and Na+/Ca2+ exchanger fail -> increased Na and Ca in cell, and increased Ca in mitochondria => ion increases attract free water -> swelling
(note: K+ will decrease in the cell, since Na/K exchanger is responsible for pumping Na out and K in)

115
Q

A patient (former smoker) presents w/ decreased breath sounds in the right hemithorax, and CXR reveals opacification of right side and left sided pleural effusion and tracheal deviation to the right. What may be the cause?

A

Right main stem bronchus cancerous lesion -> preventing ventilation of right lung -> alveolar collapse on that side (atelectasis)

116
Q

How can you differentiate pneumothorax and atelectasis?

A

Pneumothorax shows increased lucency on affected side whereas atelectasis has opacification of the hemithorax

117
Q

What is type B chronic gastritis and where is it located? what would biopsy reveal?

A

H. pylori associated -> antrum

Biopsy = Inflammatory cell infiltrate

118
Q

What is type A chronic gastritis and where is it located? What would biopsy reveal?

A

Autoimmune -> body of stomach

Biopsy = destruction of parietal cells -> pernicious anemia

119
Q

What hepatitis virus can cause a high mortality rate in pregnant women?

A

HEV - unenveloped RNA virus

120
Q

How can you calculate the excretion rate of a substance?

A

Excretion = [GFR (or inulin clearance) x Plasma concentration of substance] - [tubular reabsorption of substance]

121
Q

Which drugs can increase Lithium concentrations?

A

Thiazide diuretics, ACE inhibitors, and NSAIDs

122
Q

What is a minor criteria for ARDS and what associated physiological factor would be normal because of this?

A

Absence of cardiogenic pulmonary edema -> Pulmonary capillary wedge pressure usually normal in ARDS

123
Q

What occurs as a result of diffuse damage to pulmonary endothelum and/or alveolar epithelium in ARDS?

A

Increased pulmonary capillary permeability and leaky alveolocapillary membrane -> interstitial and intra-alveolar edema, inflammation, and hyaline membrane formation -> decreased lung compliance, increased work of breathing and decreased oxygen diffusion capacity -> severe state = V/Q mismatch

124
Q

What is the cell type of ovarian epithelium?

A

Simple cuboidal

125
Q

What factor determines the rate of ventricular contractions in someone with A-fib?

A

AV node refractory period

126
Q

When does the purkinje system assume pacemaker activity?

A

Severe bradycardia (

127
Q

What is determined by bundle branch conductivity?

A

Duration of QRS complexes -> widened when there is bundle branch block

128
Q

What is the direct result of mutations in beta-thallasemia disorders? What is normal in these patients

A

Mutations cause aberrant splicing of precursor mRNA or premature chain termination during mRNA translation (misfolded globin proteins precipitate later and cause membrane instability)

heme and alpha chain synthesis is normal -> increased formation of hemoglobin F and hemoglobin A2)

129
Q

What are the characteristics of Shigella species?

A

Gram negative non-motile rods, oxidase negative, acid stable, non-lactose fermenting on MacConkey, ferment glucose w/o gas production (contrast w/ E. Coli), green colonies on hektoen agar (aka do not produce H2S, contrast w/ Salmonella which does -> black pigment)

130
Q

What is hektoen agar?

A

Triple sugar iron

131
Q

What is the major pathophysiological renal abnormality w/ prolonged NSAID use, and what would be seen on biopsy?

A

Chronic interstitial nephritis => patchy interstitial inflammation, w/ subsequent fibrosis, necrosis and scarring of renal papillae, distortion of calceal architecture, and tubular atrophy (glomeruli and vascular channels often normal)

132
Q

What are the radiographic findings in someone w/ gallstone ileus?

A

Intestinal gas pattern consistent w/ intestinal obstruction, and pneumobilia (air in biliary tree, in 50% of patients)

133
Q

What results from echinococcosis? What are risks of treatment?

A

Hydatid cysts most often in liver (also lung, muscle and bone) -> rupture during cyst transection would cause anaphylaxis

134
Q

What is the first choice for treating hirsutism in patients w/ PCOS?

A
  • OCPs -> suppress LH secretion from pituitary -> decreased ovarian androgen production
  • OCPs also increase sex hormone binding globulin production by liver -> decreases free testosterone

(antiandrogens only when OCP fails, and must make sure patient is on reliable contraception as these drugs are destructive to male fetus)

135
Q

How do T3/T4 transmit their effects? What other compounds work like this?

A

Nuclear receptors - VETT CAP

-Vitamin D, Estrogen, Testosterone, T3/T4, Cortisol, Aldosterone, progesterone

136
Q

Which endocrine hormones use a cAMP signaling pathway?

A

FLAT ChAMP use cAMP

-FSH, LH, ACTH, TSH, CRH, hCG, ADH (via V2 receptor), MSH, PTH, calcitonin, GHRH, glucagon

137
Q

Which endocrine hormones use the IP3 signaling pathway?

A

GOAT HAG - GnRH, Oxytocin, ADH (V1 receptor), TRH, HIstamine (H1-R), Angiotensin II, Gastrin

138
Q

What are the characteristics of Alkaptonuria?

A
  • Autosomal recessive defiency of Homogentisate oxidase -> blocks metabolism of Phe and Tyr (at the level of homogenistic acid), preventing conversion of Tyrosine -> fumarate
  • Homogentisic acid accumulates -> excreted in urine -> imparts black color when left to sit (-nuria = negro uria)
  • Homogentisic acid binding to connective tissue, tendons and cartilage -> black pigmentation of ears, nose and cheeks
139
Q

What is meconium ileus and what is the most common cause of this? What are patients with this condition most likely to die from?

A
  • Green fecal mass obstructing the lumen of the ileum (this mass is dehydrated meconium) -> most often caused by Cystic Fibrosis (since GI secretions are thick from low Cl secretion and thus low H2O, excess water is absorbed from meconium)
  • 80% of CF deaths in US are from cardiopulmonary complications (pneumonia, bronchiectasis, bronchitic obstructive pulm disease, and cor pulmonale)
140
Q

If membrane potential in a neuron drops to a more negative level after depolarization, what does that indicate?

A

Membrane becomes permeable to ions w/ a negative equilibrium potential (e.g. K+ going out or Cl- coming in)

141
Q

What can be used to control symptoms in someone who has a disseminated carcinoid tumor (carcinoid syndrome)?

A

Octreotide -> synthetic analog of somatostatin -> acts on somatostatin receptors to inhibit secretion of many hormones and hormone like substances

142
Q

What are the compensatory reactions following nephrotic syndrome?

A
  • Very high loss of protein -> stimulates increased albumin production but liver can’t keep up -> decreased oncotic pressure -> edema and depletion of intravascular volume -> secondary hyperaldosteronism and ADH to compensate -> Na and H20 retention which exacerbates edema
  • Additionally live increases synthesis of ALL proteins (e.g. LIPOPROTEIN LIPASE) and Hyperlipidemia and Lipiduria develop
143
Q

What are the main effects of Vitamin E deficiency? What disease does this mimic?

A

Degeneration of spinocerebellar tracts, dorsal column of spinal cord and peripheral nerves.

  • > end result is ataxia, dysarthria and loss of position/vibration sense
  • > these symptoms are analogous to Friedreich’s ataxia
144
Q

What is a major long term disease risk factor in PCOS?

A

Abnormally high levels of unopposed Estrogen action on edometrium -> endometrial hyperplasia -> endometrial adenocarcinoma

USMLE Wrong Answer Facts (9 decks)

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