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USMLE Step 1: Part 1 COPY > USMLE-Rx: Week of 09/26/16 > Flashcards

USMLE-Rx: Week of 09/26/16 Flashcards

1
Q

Certain antimalarial drugs can trigger what disease to manifest symptoms?

A

Glucose-6-phosphate dehydrogenase deficiency (due to oxidative stress of quinines)

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2
Q

Posterior infarctions appear as __________ on anterior ECG leads.

A

ST depressions

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3
Q

How does tacrolimus work?

A

It binds to the intracellular protein FKMP-12 and inhibits the activation of T cells. (Tacrolimus = T cell suppressor)

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4
Q

Doxorubicin works by two mechanisms: _________________.

A

noncovalent intercalation and generation of free radicals

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5
Q

True or false: the medial umbilical ligaments are remnants of fetal blood vessels.

A

True

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6
Q

The vagus nerve is ___________ to the internal jugular within the __________ sheath.

A

posterior; carotid

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7
Q

Adenosine deaminase deficiencies lead to ______________.

A

SCID

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8
Q

What specific protein is defective in ataxia telangiectasia?

A

ATM kinase (involved in non-homologous end joining)

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9
Q

Fracture of the proximal humerus can affect which muscle?

A

The deltoid –the axillary nerve wraps around the surgical neck of the humerus; atrophy of this muscle takes a couple weeks to develop, but once it does you can notice a flattening of the shoulder

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10
Q

Fibrinous pericarditis is a condition in which _____________.

A

the pericardium exudes fibrin; it often occurs post-MI and its symptoms are relieved by leaning forward

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11
Q

Occlusion of the right-coronary artery manifests with what ECG findings?

A

ST elevation in leads II, III, and aVF

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12
Q

Most people are “right-heart dominant.” What does this mean?

A

That the right coronary supplies the posterior interventricular artery

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13
Q

Which branch of the coronary artery supplies the nodes?

A

Right coronary (to both AV and SA)

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14
Q

Blood loss leads to what kind of anemia?

A

Iron deficiency!!!

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15
Q

Fanconi anemia is an autosomal ____________ disorder of a protein that ______________. As such, when people with Fanconi anemia are given ___________ they develop aplastic anemia.

A

recessive; repairs DNA; DNA-damaging agents (such as cyclophosphamide)

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16
Q

What should you ask about if a patient presents with gangrene and ulceration of the digits?

A

Smoking history! For Buerger’s disease

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17
Q

In addition to treating the myelosuppressive side effects, administering folinic acid also treats _____________.

A

GI symptoms (such as nausea, diarrhea, or vomiting); this is so because the fast-dividing cells of the GI tract are also killed by methotrexate.

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18
Q

True or false: leukotriene B4 mediates bronchoconstriction.

A

False! B4 is the chemotactic cytokine –C4 is the bronChoConstriCtor (almost thought I Could get away with that, hehe).

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19
Q

The only TCA approved for OCD is ___________.

A

clomipramine

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20
Q

What is the key clinical presentation that distinguishes MS from other neuropathic diseases?

A

A variety of symptoms separated by time, place, and type of neuron; for instance, it may present as paresthesia in the left foot followed by weakness in the right thigh muscles

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21
Q

Describe the presentation of Guillain-Barré syndrome.

A

GBS is a disorder in which T cells target Schwann cells. As such, people typically present with ascending weakness and paresthesia (recall that both motor neurons and A-delta neurons are myelinated).

It often presents 2-3 weeks after a GI illness – commonly campylobacter jejuni – as an ascending paralysis. The paralysis typically resolves, because peripheral axons are able to regrow, but about 1/4 of patients need respiratory support. IVIG and plasmapheresis can speed recovery, but corticosteroids don’t help.

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22
Q

What enzyme is targeted by bactrim?

A

Dihydropteroate reductase

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23
Q

Describe a crossover study.

A

Patients are enrolled in one group (control or experimental) and then switched after some time

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24
Q

Hairy cells present as ________________.

A

B cells with little projections

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25
Q

A patient presents with uvular deviation to the right. What lower-motor neuron is likely to have been lesioned?

A

Left vagus; the vagus nerves lift the palate

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26
Q

What MRI finding is often seen in those with MS?

A

Periventricular white-matter plaques

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27
Q

A common comorbidity with Alzheimer’s is ______________.

A

depression

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28
Q

Those who have positive Lhermitte sign have what symptoms?

A

Lhermitte sign = pain with neck flexion = MS

INO, urinary incontinence, gait disturbances, paresthesias, periodic symptom remission, cranial nerve dysfunction

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29
Q

What neurotransmitter typically goes down with age?

A

Acetylcholine –responsible for sleep, and thus is implicated in elderly insomnia

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30
Q

What cytokine is given to those with leprosy?

A

Interferon-gamma

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31
Q

What causes defect in class switching?

A

Defective CD40 on B lymphocytes (just like the 40-year-old virgin who couldn’t switch out of the class of “virgin”) that mediates class switching; it is X-linked, so only found in males

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32
Q

Which antihypertensive causes first-dose hypotension?

A

Prazocin

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33
Q

Describe the naming system for spina bifida.

A

It’s extremely easy: meningo = meninges; myelo = spine; hydro = ventricle; and encephalo = brain.

  • meningomyelocele = herniation of the spine and meninges through a sac into the vertebral arch
  • meningocele = herniation of just the meninges into a sac on the vertebral arch
  • meningohydroencephalocele = herniation of the meninges, ventricles, and brain out of the skull
34
Q

Korsakoff amnesia results from ______________.

A

destruction of the mammillary bodies due to Wernicke’s encephalopathy; associated with profound memory loss and confabulation to fill in gaps (“Kor me another, bartender!”)

35
Q

What parts of the spine does tabes dorsalis affect?

A

The dorsal columns (of white matter). As such, vibration and fine-touch sensations are impaired.

36
Q

B12 deficiency causes degeneration of which spinal parts?

A

Lateral corticospinal tract (UMN) and dorsal column

37
Q

True or false: folate deficiency causes neurologic problems.

A

False (only B12)

38
Q

“Dilation within the cervical spinal cord” = _________________.

A

syringomyelia

39
Q

What neurologic manifestations does Chiari I cause?

A

Syringomyelia –a potential outcome of Chiari I – can lead to a “cape-like” loss of pain and temperature sensations, because they often present at C8-T1 and occlude the anterior white commissure of the upper extremities.

40
Q

MS can lead to what abnormal finding in the CSF?

A

Oligoclonal IgG

41
Q

True or false: severing the arcuate fasciculus leads to impaired repetition.

A

True

42
Q

Demeclocycline is sometimes used in _____________.

A

SIADH (it is an ADH antagonist)

43
Q

Other than spironolactone and eplerenone, these are also potassium-sparing diuretics: ______________.

A

amiloride and triamterene

44
Q

Huntington’s disease leads to loss of _____________ in the caudate.

A

GABA-ergic neurons

45
Q

Hypocalcemia leads to QT ___________________.

A

prolongation, because potassium

46
Q

The T wave represents ________________.

A

ventricular repolarization

47
Q

Skeletal abnormalities are found in neurofibramatosis type _______.

A

I

48
Q

Desmin and vimentin are types of ______________.

A

INtermediate filaments (get it?); desmin is found in muscle cells and vimentin is found in fibroblasts (Vying = FIghting)

49
Q

Describe the genetics of tuberous sclerosis.

A

Found on chromosomes 9 and 16; affects the tuberin and hamartin protein

50
Q

Epilepsy is common in what neurocutaneous disorder?

A

Tuberous sclerosis

51
Q

True or false: the vagus nerve innervates branchial arch 4.

A

True! Remember, however, that the swallowing muscles arise from the 4th arch and the speaking muscles from the 6th arch, yet both are innervated by the vagus.

52
Q

Sodium bicarbonate is used to treat what overdose?

A

TCAs!!

53
Q

Describe the mechanism of the drug commonly used to treat BPH.

A

Finasteride inhibits 5-alpha reductase, which normally converts testosterone to dihydrotestosterone (DHT). DHT stimulates mitogenic growth of the prostate, so inhibiting it lessens the growth.

54
Q

Be sure to avoid drugs with ______________ side effects in BPH patients.

A

anticholinergic (such as first-generation low-potency antipsychotics, TCAs, etc.)

55
Q

What causes deficient antibody transfer to babies?

A

Being premature
HIV
Placental malaria
Maternal immunodeficiency

56
Q

True or false: CLL typically presents with proliferation of T cells.

A

False! It’s B lymphocytes (“crushed little BaLLs”)

57
Q

Sustained exercise leads to ___________ in arteriolar resistance.

A

decrease (because increases in extracellular potassium, lactate, and adenosine lead to vasodilation with prolonged exercise)

58
Q

What spinal abnormality presents with a tuft of hair on the lower back?

A

Spina bifida occulta

59
Q

Histologic examination of the calf muscles of a boy with an out-of-frame mutation in the dystrophin gene would show _______________.

A

fibrofatty replacement of muscle (this is Duchenne’s)

60
Q

True or false: type 2 muscle fibers are fast twitch.

A

True. “2 Fast, 2 Furious”

61
Q

What disorder presents with linear antibodies on the dermal-epidermal junction?

A

Bullous pemphigoid – results from antibodies to hemidesmosomes

62
Q

“Ash leaf spots” are seen are patients with a genetic disorder that leads to an increase in what cancers?

A

Astrocytomas and angiofibromas (this is autosomal dominant tuberous sclerosis)

63
Q

Cholinergic neurons in the globus pallidus have been shown to be lost in _______________.

A

Alzheimer’s disease

64
Q

Proteas mirabilis produces struvite stones because ______________.

A

it produces urease (an enzyme that cleaves urea to produce alkaline ammonia)

65
Q

Patients that lack a certain enzyme will have macrophages with brown-staining vacuoles on toluidine blue staining. What enzyme are they missing? What symptoms would they have?

A

Arylsulfatase A; without this enzyme –which is lost in metachromatic leukodystrophy, an autosomal recessive disorder –cerebroside sulfate accumulates in vacuoles and patients have central and peripheral nerve problems (e.g., walking disturbance, strabismus)

66
Q

Transvaginal nerve blocks are achieved by blocking which nerve?

A

The pudendal (S2 - S4)

67
Q

Zero-order elimination occurs when _________________.

A

the enzyme that metabolizes the drug is saturated; this occurs commonly with Phenytoin, Ethanol, and Aspirin (“zero PEAs for me, please”)

68
Q

What vitamin can raise HDL levels? What side effects can this have?

A

Niacin (B3); cutaneous flushing –alleviated by aspirin

69
Q

What are the two most common causes of subarachnoid hemorrhage?

A

1) Rupture of arterial aneurysm
2) Rupture of arteriovenous malformation

Leads to blood following the course of the sulci

70
Q

What is the hallmark pattern of middle medullary syndrome?

A

Contralateral UMN weakness of the extremities with ipsilateral hypoglossal nerve weakness.

71
Q

What laboratory technique is used to identify tandem-repeat disorders?

A

Southern blotting; so to identify Huntington’s disease, for instance, you use labeled DNA probes to tag restriction-digest-cleaved DNA to determine number of repeats

72
Q

Microglia, like other monocyte-derived cells, arises from which embryonic tissue?

A

Mesoderm

73
Q

In addition to holoprosencephaly, what features are typical of Patau syndrome?

A

Microophthalmia, cleft lip, and polydactyly

74
Q

Which artery supplies the basal ganglia?

A

Middle cerebral

75
Q

The leading cause of death among those older than 65?

A

Heart disease!

76
Q

Headaches with prominent ophthalmic involvement most often occur at ___________.

A

night

77
Q

What Parkinson’s drug is also an antiviral?

A

Amantadine

78
Q

Deficiency of which amino acid can lead to the three Ds?

A

Dermatitis, diarrhea, and dementia result from both niacin deficiency (sometimes seen in alcoholics) and tryptophan deficiency – called Pellagra for the thickened skin that usually occurs.

79
Q

Patients lacking orexin have what symptoms?

A

Narcolepsy, cataplexy (sudden loss of muscle tone in response to strong emotion), and sleep paralysis

80
Q

The occipital pole is responsible for ____________.

A

central vision

81
Q

The muscle that stabilizes the tympanic membrane is innervated by which cranial nerve?

A

This describes the tensor tympani –innervated by the trigeminal nerve; don’t confuse this with the stapedius muscle, which stabilizes the stapes (innervated by the facial nerve)

USMLE Step 1: Part 1 COPY (243 decks)

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