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STEP1 Review > UWorld Test Review 8 > Flashcards

UWorld Test Review 8 Flashcards

1
Q

failure of vitelline duct obliteration —>

A

Meckel’s diverticulum: intestinal outpouching located within 2 feet of ileocecal valve, contains gastric mucosa —> lower GI bleeding, anemia

vitelline (omphalomesenteric) duct connects midgut lumen and yolk sac, should obliterate during first trimester

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2
Q

Immunocompromised patient presents with acute confusion, fever, asymmetric lower extremity flaccid paralysis, and parkinsonism (bradykinesia, tremor). Patient just returned from Texas. CSF PCR yields viral RNA. Dx?

A

West Nile virus (flavivirus): fever + headache + rash, can be neuro-invasive in immunocompromised patients

neuroinvasive features include meningitis, encephalitis, acute asymmetric flaccid paralysis (causing Parkinsonism)

transmitted via mosquitos in warm climates

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3
Q

maternal quadruple screen shows low alpha-fetoprotein, low estriol, high beta-hCG, and high inhibin A

A

Trisomy 21

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4
Q

mid-shaft humeral fractures will damage which nerve and artery?

A

radial nerve and deep (profunda) brachial artery

[deep brachial branches from brachial artery high in arm, then courses posteriorly along the humerus in close association with the radial nerve]

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5
Q

34-year-old man presents with painful urination. PE shows watery penile discharge. Urethral swabs obtained are negative for gonococcal infection. He is treated and symptoms resolved. Two weeks later he develops, acute conjunctivitis, R knee pain, and vesicular rash on palms and soles. This patient’s condition is most likely associated with which of the following?
a. Esophageal dysmotility
b. Hyper parathyroidism.
c. Polymyositis.
d. Sacroiliitis.
e. Tabes dorsalis.

A

d. Sacroiliitis.

dx = reactive arthritis: urethritis + conjunctivitis + arthritis

Symptoms manifest 1 to 4 weeks following primary infection, skin findings include hyperkeratotic vesicles on the palms and soles

axial involvement, including sacroiliitis, may occur in some patients

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6
Q

Corkscrew shaped organism + conjunctival suffusion =

A

leptospirosis: thin, highly coiled, motile spirochete, infection via water contaminated with animal urine

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7
Q

A cyst is incidentally found in a three-year-old boy. The cyst is connected by a fibrous band to the ileum in the umbilicus. Diagnosis?

A

Meckel diverticulum: incomplete obliteration of the vitelline (omphalomesenteric) duct

vitelline duct connects midgut lumen with yolk sac, obliterates in first trimester

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8
Q

MOA and clinical use of methylnaltrexone?

A

peripherally acting mu opioid receptor antagonist

Counteracts inhibitory effect of opioids on peristalsis, treats constipation

Does not cross BBB - does not induce withdrawal symptoms

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9
Q

With which neurodegenerative disorder is accumulation of TAR DNA binding protein 43 (TDP-43) associated? (2)

A

TDP-43 functions as transcription inhibitor and DNA repair protein

accumulation of abnormally ubiquitinated TDP-43 is associated with amyotrophic lateral sclerosis and frontotemporal dementia

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10
Q

which type of drug should be initiated in a patient with ascites?

A

spironolactone (aldosterone antagonist) - induces natriuresis without blocking the critical vasoconstrictive effects of angiotensins (do NOT use ACEi, ARBs, or alpha blockers)

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11
Q

which of the following are most likely to be affected by rheumatoid arthritis?
a. cervical spine
b. lumbar spine
c. sacroiliac joints
d. thoracic spine

A

a. cervical spine - subluxation, cord compression

[sacroiliac joints is characteristic of seronegative spondyloarthropathies]

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12
Q

what are the steps of base excision repair?

A

[repairs cytosine deamination]

  1. glycosylase - cleaves altered base
  2. endonuclease cleaves 5’ end, lyase cleaves 3’ sugar phosphate
  3. DNA polymerase fills the gap, and ligase fills it
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13
Q

what are the paraneoplastic syndromes of small cell vs squamous cell lung carcinoma?

A

small cell: SIADH, Cushing’s, LEMS

squamous: PTHrP

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14
Q

which of the following is consistent with essential tremor?
a. exacerbation with alcohol
b. family history of tremor
c. previous head trauma
d. use of dopaminergic drugs

A

b. family history of tremor - often autosomal dominant inheritance

actually improves with alcohol use

tx = propranolol and primidone (anticonvulsant)

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15
Q

patient with impaired executive functioning is diagnosed with frontotemporal dementia, which is characterized by what microscopic findings? (2)

A
  1. Tau protein inclusions - neurofibrillary tangles, Pick bodies (also see in Alzheimer’s)
  2. TDP-43 protein inclusions - involved in DNA repair/transcription (also see in ALS)
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16
Q

which organ of the GI tract is derived from mesoderm, NOT endoderm?

A

spleen

also kidneys/ureters, adrenal cortex, internal genitalia, muscles, connective tissue, serosal linings (peritoneum), cardio/lymphatics

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17
Q

which of the following may cause retroperitoneal hematoma from blunt abdominal trauma?
a. pancreas
b. spleen
c. liver
d. stomach
e. colon

A

a. pancreas

all others are intraperitoneal organs

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18
Q

pharmacological treatment for narcolepsy?

A

modafinil - psychostimulant, treats daytime sleepiness

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19
Q

17yo M w/ poor vision at night, which developed ~4mo ago. There is visual loss in the mid-periphery. Normal tear function. Funduscopic exam shows bilateral optic disc pallor, attenuation of retinal vessels, and areas of dark discoloration in the retina. Dx?

A

retinitis pigmentosa: genetic loss of rods (early) + loss of cones (late)

optic disc pallor = optic nerve atrophy

pigment accumulates —> bone-spicule pattern around vessels

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20
Q

compression of the _______ nerve at the inguinal ligament by tight clothing, seat belts, pregnancy, etc, may cause meralgia paresthetica

A

lateral femoral cutaneous nerve (L2-L3) - runs lateral to psoas, exits abdomen beneath inguinal ligament

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21
Q

retinal “flame” hemorrhages =

A

malignant arterial HTN - causes painless, unilateral visual disturbances

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22
Q

narcolepsy with cataplexy is caused by lack of 2 neuropeptides:

A

hypocretin-1/2 (orexin-A/B) - produced in the lateral hypothalamus, promote wakefulness

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23
Q

2 day old infant presenting w/ signs of bowel obstruction (bilious emesis, distention). Digital rectal exam results in forceful expulsion of gas. Dx?

A

Hirschsprung disease - failure of craniocaudal migration of neural crest cells

affects rectosigmoid - unable to relax, forceful expulsion of gas/stool on rectal exam is typical

24
Q

tx for central vs nephrogenic diabetes inspidus

A

central DI tx = desmopressin (ADH analog)

nephrogenic DI tx = thiazide diuretics (induce mild hypovolemia that decreases polyuria) or NSAIDs (inhibit renal prostaglandins that act as ADH antagonists)

25
Q

baby girl w/ previously normal development now presenting with regression of speech, gait abnormalities, and stereotypical movements (clapping) =

A

Rett syndrome: sporadic X-linked mutation in MECP2 gene causes arrested brain development (NOT neurodegeneration)

26
Q

a fracture of the pterion (where frontal, parietal, temporal, and sphenoid bones meet) may cause laceration of the ______ artery (branch of the ______ artery), causing a _______hematoma

A

a fracture of the pterion (where frontal, parietal, temporal, and sphenoid bones meet) may cause laceration of the middle meningeal artery (branch of the maxillary artery), causing an epidural hematoma

external carotid —> maxillary artery —> enters foramen spinosum —> middle meningeal artery

27
Q

young child with self-mutilating behaviors and hypotonia may have a compensatory increase in activity of which of the following?
a. aspartate carbamoyltransferase
b. dihydroorotase
c. hypoxanthine-guanine phosphoribosyltransferase
d. ribonucleotide reductase
e. thymidylate synthase
f. phosphoribosyl pyrophosphate amidotransferase

A

f. phosphoribosyl pyrophosphate amidotransferase

dx = Lesch-Nyhan syndrome: XLR mutation in HGPRT, enzyme required for purine salvage

—> increased demand for de novo purine synthesis, first step of which requires **PRPP*

28
Q

what hemodynamic changes occur during the strain vs release phase of Valsalva?

A

strain phase: pressure directly transmitted to aorta —> reduced venous return + reduced CO —> compensatory rise in SVR and HR

release phase: blood surges into RA and pulmonary circulation —> increased venous return and increased vagal tone, return to baseline

29
Q

pregnant patient with heavy vaginal bleeding + tender, firm uterus =

A

placental abruption - rupture of maternal vessels at uteroplacental interface, leading to premature separation of the placenta from myometrium

risk factors = HTN/preeclampsia, abdominal trauma, cocaine/tobacco

30
Q

which artery is at risk for erosion by a posterior duodenal ulcer?

A

gastroduodenal artery - likes along posterior wall of duodenal bulb

31
Q

glutamate works through the ____ receptor and causes ____ influx

GABA works through the ______ receptor and causes ___ influx

glycine works through the ______ receptor and causes ___ influx

A

glutamate (excitatory) works through the NMDA receptor and causes Ca2+ and Na+ influx

GABA (inhibitory) works through the GABA(A) receptor and causes Cl- and HCO3- influx

glycine (inhibitory) works through the glycine receptor and causes Cl- influx

32
Q

migratory thrombophlebitis should raise suspicion for…

A

cancer - hypercoagulability is common paraneoplastic syndrome seen most frequently in visceral adenocarcinoma of the pancreas, colon, and lung

adenocarcinoma produces thromboplastin-like substance capable of causing chronic intravascular coagulation

migratory superficial thrombophlebitis = Trousseau syndrome

33
Q

which of the following occurs in germinal centers?
a. V(D)J recombination
b. negative selection
c. isotype switching

A

c. isotype switching

other options occur in bone marrow

34
Q

women who just gave birth + symptoms of hyperthyroidism =

A

postpartum thyroiditis - autoimmune destruction of thyroid follicles and release of preformed thyroid hormone

transient hyperthyroid —> brief hypothyroid —> return to euthyroid

35
Q

which gene mutation is implicated in pancreatic ductal adenocarcinoma?

A

KRAS - mutation produces constitutively active cell growth

36
Q

most patient’s hearts are [L/R] dominant, in which inferior LV wall is supplied by ______

RV is fully supplied by ______ in almost all patients

A

most patient’s hearts are right dominant, in which inferior LV wall is supplied by R coronary artery (in L dominant, supplied by L circumflex)

[just think of how most people are R handed]

RV is fully supplied by R coronary artery in almost all patients

37
Q

sudden cardiac death in a young adult (30’s) NOT a teenager/athlete =

A

familial dilated cardiomyopathy: AD mutation in TTN gene which codes for sarcomere protein titin

[recall hypertrophic cardiomyopathy is AD mutation in myosin proteins, and causes sudden cardiac death in teenagers/athletes]

38
Q

MOA bortezomib

A

binds/inhibits 26S proteasome - facilitates apoptosis of neoplastic cells in multiple myeloma by preventing degradation of pro-apoptotic factors

39
Q

differentiate the effects of prednisone, sirolimus, and tacrolimus on IL-2 signaling

A

prednisone (and other glucocorticoids) translocate to nucleus and inhibit transcription of genes that encode IL-2 and other inflammatory mediators

sirolimus inhibits mTOR, which blocks IL-2 signal transduction (intermediate in signaling pathway)

tacrolimus (and cyclosporine - calcineurin inhibitors) block translocation of NFAT, resulting in reduced transcription of IL-2

40
Q

Describe the kidney findings in a patient with hypertensive emergency

A

malignant nephrosclerosis: fibrinoid necrosis + hyperplastic arteriolosclerosis with onion skin appearance

41
Q

clinical use of phentermine, diethylproprion, and benzphetamine

A

sympathomimetic amines (stimulants) used for short-term weight loss - cause release of NE

avoid in patients with HTN and heart disease

high rate of weight re-gain

42
Q

MOA orlistat

A

orlistat: intestinal lipase inhibitor, reduces digestion/absorption of dietary fats

used for weight loss, but significant GI adverse effects

43
Q

SIADH is a paraneoplastic syndrome of _______ lung cancer

A

small cell carcinoma - neuroendocrine origin

SIADH causes euvolemic hyponatremia

44
Q

explain why fibrates (gemfibrozil) increase risk of gallstones

A

fibrates inhibit rate-limiting enzyme in bile acid synthesis - cholesterol 7-alpha-hydroxylase

reduced bile acid production causes decreased cholesterol solubility —> risk of cholesterol gallstones

45
Q

patient with pneumoperitoneum due to perforated viscus (most commonly duodenal ulcer) may present with referred pain to…

A

shoulder pain due to referred pain from diaphragmatic irritation

46
Q

MOA rifaximin

A

rifaximin: non-absorbable antibiotic that alters GI flora to decrease intestinal production and absorption of ammonia

used in addition to lactulose

also sometimes used for traveler’s diarrhea because it inhibits bacterial RNA synthesis via binding DNA-dependent RNA polymerase

47
Q

which of the following is a normal age-related finding?
a. decreased bone marrow mass
b. decreased medullary cavity size
c. decreased RBC life span
d. increased extramedullary hematopoiesis
e. increased marrow fibrous tissue

A

a. decreased bone marrow mass - replaced with adipose (but not fibrosis)

48
Q

highly soluble anesthetic have [fast/slow] onset of action

A

high solubility = SLOW onset

49
Q

name 4 mood stabilizers for bipolar disorder

A
  1. lithium
  2. valproate
  3. carbamazepine
  4. lamotrigine
50
Q

patient post-MVC accident presenting with L shoulder pain, nausea, and hiccups. Thoughts?

A

ruptured spleen —> irritated phrenic nerve sensory fibers around diaphragm (C3-C5), causing referred pain to shoulder (C3-C5 region) + hiccups due to spasmodic contractions pulling air against closed larynx

51
Q

nitric oxide is synthesized from which amino acid?

A

arginine

arginine + O2 + NADPH —> NO + citrulline

NO then activates guanylate cyclase, triggering production of cGMP

this process is stimulated by ACh, bradykinin, serotonin, substance P, and sheer stress

52
Q

patient with uncontrolled ulcerative colitis presents with abdominal pain/ distention, bloody diarrhea, fever, and shock. Thoughts?

A

toxic megacolon - complication of UC in which severe inflammatino causes colonic smooth muscle paralysis

abdominal X-ray shows colonic dilation and multiple air-fluid levels or free air (in case of rupture)

53
Q

immunocompromised patient presents with infection of the paranasal sinuses + biopsy showing 90* nonseptate hyphae =

A

either Mucor, Rhizopus, or Absidia causing mucormycosis

54
Q

what is the sequence by which Hep B replicates?

A

dsDNA —> +RNA template —> partially dsDNA progeny

55
Q

how do the symptoms of Friedreich ataxia and Charcot-Marie-Tooth disease differ?

A

Friedreich ataxia: GAA expansion causes degeneration of spinocerebellars tracts —> gait ataxia, loss of prop/vibration, kyphoscoliosis and peds cavus (high foot arch), hypertrophic cardiomyopathy, diabetes mellitus

Charcot-Marie-Tooth: AD demyelination of peripheral nerves —> distal leg weakness/atrophy, sensory deficits, kyphoscoliosis and pes cavus (NOT cardio)

56
Q

which of the following describes diabetic neuropathy?
a. endoneurial inflammatory infiltration
b. poor signal transmission at the neuromuscular junction
c. endoneurial arteriole hyalinzation

A

c. endoneurial arteriole hyalinzation

nonenzymatic glycosylation —> hyalinization of endoneurial arteries —> ischemic nerve damage

57
Q

patient presenting with depression, fatigue, hypersomnia, hyperphagia, and vivid dreams is characteristic of ______ withdrawal

A

patient presenting with depression, fatigue, hypersomnia, hyperphagia, and vivid dreams is characteristic of cocaine withdrawal

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