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USMLE Step 1: Part 1 COPY > USMLE-Rx: Week of 09/19/16 > Flashcards

USMLE-Rx: Week of 09/19/16 Flashcards

1
Q

Gastric parietal cells secrete a protein that does what?

A

Intrinsic factor binds to free cobalamin in the small intestine and binds to a surface receptor in the ileum.

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2
Q

True or false: B12 deficiency leads to normal methylmalonic acid and increased homocysteine.

A

False! B12 leads to increases in BBBBBBBBBBBBBoth (that’s 12 Bs… remember it)

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3
Q

Among the beta-blockers, what is special about esmolol?

A

It is extremely short acting. It’s half-life is nine minutes. (Just think of Esme –her career was shortened.) As such, it is often given as a trial drug.

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4
Q

Describe Turcot syndrome.

A

Think of it as a syndrome in which you get cancer in the spot that holds your TURban and your COlon.

Genes: FAP (APC) and CNS

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5
Q

What drug should be given to someone taking cyclophosphamide?

A

Mesna (a guy riding a CYCLE drinking a PHOSPHAte riding into SNAres on a MESa)

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6
Q

How does PTH affect the kidney?

A

Increasing calcium absorption
Decreasing phosphate reabsorption
Increasing conversion of 25-dihydroxycholcalciferol to 1,25-dihydroxyvitamin D

PTH wants to increase calcium in the blood and decrease phosphate.

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7
Q

What stain indicates from asbestos exposure?

A

Yellow-brown, rod-shaped bodies on Prussian blue.

Also called “ferruginous bodies.”

Asbestos picks up iron and calcium.

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8
Q

_____________ allows calcium to be pumped into the sarcoplasmic reticulum when it is phosphorylated.

A

Phospholambin

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9
Q

What is the KEY difference in differentiating PSGN and allergic interstitial nephritis?

A

Time! Allergic interstitial nephritis will occur within a couple days of drug allergy (specifically antibiotics), while PSGN will be a couple weeks later.

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10
Q

What EKG finding is typical of a Marfan’s patient with chest pain?

A

Decreased QRS amplitude

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11
Q

What is a positive Homan sign? What condition does it indicate?

A

Pain with dorsiflexion

DVT

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12
Q

True or false: thromboxane A2 stimulates vasodilation.

A

False! TXA2 stimulates platelet aggregation and vasoconstriction.

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13
Q

What cells have infiltrated the kidneys in acute pyelonephritis?

A

Neutrophils

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14
Q

Smoking and asbestos together lead to increased risk of ______________.

A

bronchogenic carcinoma (even more than mesothelioma); also, bronchogenic carcinoma is the most common cancer to result from asbestos, even in the absence of smoking

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15
Q

Ghon complexes develop into __________ complexes.

A

Ranke (these are calcified nodules from tuberculosis)

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16
Q

True or false: there are no caseating granulomas in miliary tuberculosis.

A

False. The abundant small lesions are tiny granulomas.

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17
Q

Dantrolene is also given to those with _____________.

A

neuroleptic malignant syndrome

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18
Q

Besides abundant vasculature, hemangioblastomas also present with what histologic feature?

A

Foamy macrophages (think of the foam on you Von Hippel Latté)

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19
Q

Besides Homer-Wright rosettes, the neoplasm that frequently appears on the cerebellar vermis has what histologic pattern?

A

Small cells with a high nuclear-to-cytoplasm ratio

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20
Q

Compare NF-1 and NF-2.

A

NF-1:

  • mutation of the tumor-suppressor neurofibrin on chromosome 17 (negatively regulates RAS)
  • leads to café-au-lait spots, Lisch nodules, optic gliomas, and pheochromocytoma
  • derived from neural crest cells

NF-2:

  • mutation of merlin, a cytoskeletal protein on chromosome 22q
  • leads to bilateral vestibular Schwannomas, meningiomas, gliomas, neurofibromas, and lenticular opacities
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21
Q

What smooth muscle contracts in the scrotum to reduce heat loss?

A

Dartos

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22
Q

What are the layers of tissue from outside to inside of the spermatic cord and their corresponding derivations?

A

External spermatic fascia (a continuation of the external oblique)
Cremasteric muscle and fascia (a continuation of the internal oblique)
Internal spermatic fascia (a continuation of the transversalis fascia)

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23
Q

Other than carbon monoxide poisoning, what pulmonary/hematologic problems can house fires cause?

A

Cyanide toxicity (because synthetic materials like furniture can release cyanide when burned)

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24
Q

Describe the pathophysiology and treatment of cyanide poisoning.

A

Cyanide poisons cytochrome C in the electron transport chain, thus stimulating more anaerobic metabolism. With more anaerobic metabolism, lactic acid builds up and leads to anion-gap metabolic acidosis.

Nitrites and thiosulfates treat cyanide by producing methemoglobin, which acts as a sponge fore cyanide.

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25
Q

What is the correct term for loss of lateral-field vision?

A

Bitemporal hemianopsia

26
Q

A certain enterovirus can lead to heart problems. What is it? Describe its pathophysiology.

A

Coxsackie B virus can lead to myocarditis and eventual dilated cardiomyopathy

27
Q

An adult who “can’t see out of the corners of their eyes” and has decreased sexual drive most likely has a ______________.

A

prolactinoma –the most common sellar tumor in adults

28
Q

Describe the presenting signs and prognosis/treatment of acute intermittent porphyria.

A

The five Ps:

  • polyneuropathy
  • psychiatric disturbances
  • port-wine stains
  • precipitated by drugs
  • painful abdomen

Untreated, AIP can be fatal. Give glucose and heme, which inhibit ALA synthase.

29
Q

Describe the mechanism of colchicine.

A

It binds and inhibits microtubule polymerization (like vincristine/vinblastine). This impairs the mitosis and migration of neutrophils/granulocytes, and can prevent undesired inflammation.

Colchicine is second-line treatment for gout because of its toxic effects.

30
Q

What heart medication can mask hypoglycemia and how does it do so?

A

Beta-blockers.

One of the symptoms of hypoglycemia is tachycardia, which will be masked by beta-blockers.

31
Q

True or false: Takayasu’s arteritis affects the coronary vessels.

A

False –only the aortic arch

32
Q

What are the nitrosureas chemotherapies?

A

Carmustine and streptozocin

33
Q

Busulfan works by ______________. What cancer is it commonly used in?

A

alkylation; CML

34
Q

True or false: abnormal airway dilation in the elderly sometimes presents with hemoptysis.

A

True! This is an effect of bronchiectasis

35
Q

There are four disorders that test positive for p-ANCA: ___________________.

A
  • microscopic polyangiitis
  • Churg-Strauss
  • ulcerative colitis
  • polyarteritis nodosa
36
Q

What antiarrhythmic can cause dizziness, vertigo, and torsades?

A

Quinidine (a class IA drug, like procainamide and disyopyramide)

37
Q

Functional residual capacity is equal to ______________.

A

expiratory reserve volume and residual volume

38
Q

True or false: ataxia telangiectasia is caused by an enzyme that fixes double-stranded breaks.

A

True! It is involved in non-homologous end joining.

39
Q

Other than ataxia telangiectasia, what other disorder involves DNA repair pathways and ataxic gaits?

A

Xeroderma pigmentosum! Up to 20% of patients with this disorder, which is caused by a defect in nucleotide excision repair, have neurologic manifestations.

40
Q

What disorder presents with vaginal bleeding, increased uterine size, and elevated levels of beta-human chorionic gonadotrophin?

A

Hydatidiform moles. This is a disorder in which the chorionic villi swell with cystic lesions. It must be removed and treated with methotrexate, or it can lead to choriocarcinoma (which metastasizes quickly).

Complete moles are caused by sperm fertilization of an enucleated egg, while partial moles are caused by two sperm fertilizing one egg (HydatidifoRM = High speRM). Also, PARTial moles have fetal PARTs.

41
Q

How would you differentiate between hydatidiform moles and ruptured ectopic pregnancy?

A

Ruptured moles will have much less bleeding.

42
Q

What is a delta wave?

A

A “slurred” upslope of the QRS complex from additional – i.e., non-AV –electrical connections between the atria and the ventricles.

This is Wolff-Parkinson-White syndrome. Type A is when the additional circuit is through the left side (and is more common), while type B is through the right.

Often benign, but can lead to supraventricular tachycardia (

43
Q

Which type of class I antiarrhythmics slow the action potential AND prolong the effective refractory period?

A

IA (procainamide, disopyramide, and quinidine)

IA = Also block the potassium channels.

44
Q

What are the class IB antiarrhythmics, and what is their function?

A

Lidocaine and mexiletine (“I’d Buy LIDia’s MEXIcan Tacos.”)

They preferentially target ischemic or damaged tissue, so they’re useful in stopping ventricular arrhythmias from heart attacks (or digitalis-induced arrhythmia).

They slow phase 0 but decrease the overall action potential.

45
Q

What are the class IC antiarrhythmics? What is their indication?

A

Flecainide and propafenone (“I Could have FrIes, Please?”)

They significantly prolong the effective refractory period in accessory tracts and the AV node, so their used in SVTs and atrial fibrillation.

46
Q

Basic lab finding: “M-spike” does not necessarily mean Ig___.

A

M (it could be IgG; it just means monoclonal)

47
Q

The aortic pathology that occurs with an STD also occurs in what genetic disorder?

A

Marfan’s (it’s called cystic medial necrosis)

48
Q

The _________ nerve is compromised in carpal tunnel syndrome. What muscles are affected by this?

A

median; flexion of the MCP joint and the abductor pollicis, opponens pollicis, and flexor pollicis (which is why they have thenar atrophy)

49
Q

What enzyme metabolizes purines?

A

Xanthine oxidase, which can be inhibited by allopurinol (1st step) or febuxostat (2nd step)

50
Q

True or false: probenecid leads to increased secretion of uric acid.

A

False! It leads to decreased reabsorption.

51
Q

A schizophrenic man presents with stiff arms and red urine that does not test positive for hematuria. What two drugs should you consider for treating this condition?

A

Dantrolene and bromocriptine (it is your BRO that helps MOve the limbs that are stiff as corpses in a CRyPT)

52
Q

Why is isoniazid used to treat tuberculosis?

A

Because it inhibits mycolic acid synthesis

53
Q

A patient presents with visual changes, including red-green color blindness, after being treated for tuberculosis. What is the mechanism of the drug they took?

A

Ethambutol is a drug used to kill tuberculosis. It inhibits the arabinosyl transferases, thus disrupting the mycoplasmic cell wall.

54
Q

True or false: exercise is better at preventing DVTs than smoking cessation.

A

False. Although exercise, and activity specifically, is good for preventing DVTs, smoking leads to a hypercoagulable state.

55
Q

What are the symptoms of Lyme disease?

A 
It's a key Lyme pie to the FACE! 
Facial nerve palsy (asymmetric smile) 
Arthritis
Cardiac block
Erythema migrans (annular rash)
56
Q

There is an antineoplastic that can cause oral and gastrointestinal ulcerations if given orally. What is its mechanism?

A

It inhibits thymidylate synthase (this is 5-fluorouracil), thereby leading to decreased cell turnover.

57
Q

True or false: cyclophosphamide works by modifying an intracellular transcription factor.

A

False. It is a DNA alkylating agent.

58
Q

What drugs are used to treat Hodgkin’s?

A 
ABVD 
Adriamycin (doxorubicin) 
Bleomycin
Vinblastine
Dacarbazine
59
Q

What does a negative nitroblue tetrazolium dye reduction test mean?

A

That the patient doesn’t have the ability to reduce the dye and thus likely has NADP oxidase deficiency (called chronic granulomatous disease)

60
Q

Those who lack IgA (congenitally) most often have what symptoms?

A

Most are actually asymptomatic, but some do have increased URI/GI infections or can have anaphylactic reactions to IgA-containing products.

61
Q

Milrinone is used for _________ shock.

A

cardiogenic (it is an inotropic agent –it helps the MILl to crank up)

62
Q

True or false: give epinephrine to someone in hypotensive shock.

A

False. Epinephrine stimulates the beta receptors and is thus better suited to treat cardiogenic shock. Norepinephrine activates alpha receptors and raises blood pressure.

USMLE Step 1: Part 1 COPY (243 decks)

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