UWORLD practice test

Question 1

Peutz-Jeghers syndrome

• inheritance pattern
• phenotypes

Answer 1

• autosomal dominant

- hyperpigmented lips, multiple harmartomas in GI (abdominal discomfort)

Question 2

What does desmosome connect?

Answer 2

keratinocytes

• note that keratinocyte span basically entire epidermis layers. I thought it was just startum corneum, but startum corneum is composed of DEAD keratinocytes

Question 3

postural tremor: what brain lesion?

Answer 3

cerebellum

• postural tremor, tremor during MOVEMENT, is different from resting tremor.

Question 4

Intussusception vs. Merkel diverticula: how patient presents differently?

Answer 4

• Intussusception: palpable abdominal mass with severe pain, current jelly stool
• Merkel diverticula: occult GI bleeding, but NOT palpable mass, NOT severe pain
• note that Merkel diverticula can be leading point of intussusception

Question 5

What does primase do?

Answer 5

making RNA primers for DNA replication (lagging strand)

Question 6

metoclopramide is contraindicated with patient with what disease?

Answer 6

Parkinson

Question 7

What is color of urine after exposure to air in alkaptouria?

Answer 7

black

• this is the only BLACK urine (not red- nephritic, not orange- rifampin toxicity, not brown- rhabdomyolysis, not portwine- acute intermittent porphyria)
• question presents kid with black wet diaper

Question 8

phenotypes of alkaptouria?

Answer 8

• black urine
• blue/black spots on skin/sclera
• arthralgia (homogentisic acid is toxic to cartilage)

*OSTEOARTHROPATHY was answer

Question 9

What is shake test?

Answer 9

mix ethanol with amniotic fluid and shake
=> surfactant foams stable ring with ethanol
=> useful diagnostic test to check enough quantity of surfactant is formed

Question 10

Why heparin is safe for pregnant?

Answer 10

it is highly water soluble, not crossing placenta

Question 11

What two types of tissues consist of liver cirrhosis?

Answer 11

• fibrotic tissue (from stellate cells)

- regenerative nodules (proliferating HEPATOCYTES)

Question 12

female patient who has been failing to concept. regular menstural cycle, normal physical exam, history of unprotected sex. male partner is also normal. what would be possible cause?

Answer 12

history of unprotected sex is key here.

SUBCLINICAL PID (previous PID) can still cause infertility as it could previously damage fellopian tubes.

although patient’s physical exam is normal. ALWAYS think about PREVIOUS/ SUBCLINICAL PID for patient with unprotected sex history

Question 13

History of field trip. Differentiate morphology of rash

• delayed hypersensitivity
• rocky mountain spotted fever

Answer 13

• delayed hypersensitivity: streaks (scratchy)

- rocky mountain spotted fever: maculopapular rash

Question 14

What is etiology of later development of lactose intolerance?

Answer 14

decreased GENE EXPRESSION of lactase over the time

commonly affected in Asian, African, native American

Question 15

Is prolonged bed rest recommended for back pain

Answer 15

no. it can prolong pain.

moderate activity is more recommended

Question 16

what is pathophysiology of extrapyrimidal side effects upon

Answer 16

up-regulation dopamine receptors or compensatory hypersensitivity of dopamine receptors to dopamine

• remember, dopamine works to enhance movement. extrapyrimidal side effects include crazy movements, that is it is MORE of DOPAMINE ACTIVITY, NOT due to DOPAMINE BLOCKADE
• I picked ACUTE D2 blockade. but question said “years of medication”. meaning that it is more like chronic effect, not acute blockade

Question 17

What is “contact inhibition” when two cells are growing on petri dish? how do cancer cells behave differently?

Answer 17

As cells are growing and contact each other, cell stops growing. This effect is mediated by cadherin

cancer cells can evade from cadherin, so they can still grow even when two cells contact each other

Question 18

How can female present hemophila A?

Answer 18

skewed X inactivation

• normally one of female X chromosome is randomly inactivated so that both male and female present with similar gene expression dosage. This inactivation ratio is normally 50:50. But skewed X inactivation may result in 70:30 inactivation. if hemophilia A gene is in 30 inactivation portion, they can present hemophila A
• this applies to any kind of X linked recessive disease

Question 19

BP while standing: 85/60
BP while sitting: 120/80
what is underlying pathophysiology?

Answer 19

orthostatic hypotension

understimulation of ALPHA receptor to maintain PERIPHERAL blood pressure

• I picked understimulation of beta 1 receptor, but this is not really true. Heart is already pumping (unless there is heart disease). so it is peripheral vasculature that is in charge of maintenance of blood pressure
• remember that common side effect of alpha blocker is orthostatic hypotension

Question 20

what nephrotic syndrome is commonly associated with solitary tumor?

Answer 20

membranous nephropathy

Question 21

probenicid usage for

• cidofovir
• gout
• penicillin

Answer 21

for gout and cidofovir probenecid is used for same reason via same mechanism:
probenecid inhibits renal tubular reabsorption so that it reduces toxicity

for penicillin, probenecid is used to increase drug efficacy for exactly opposite mechanism:
probenecid inhibits renal tubular excretion so that it allows penicillin to stay in the system longer, enhancing efficacy

Question 22

explain physiology how chronic cough results in syncope

Answer 22

cough: sort of exaggerated exhale
- > increase in intrathoracic pressure
- > decreased venous return

Question 23

what is pathophysiology of spider angiomata in liver cirrhosis

Answer 23

estrogen excess due to decreased estrogen metabolism by liver

*gynecomastia is also same!

Question 24

Adhesions in pelvic area: diagnosis?

Answer 24

endometriosis

Question 25

complication of untreated endometriosis?

Answer 25

infertility

Question 26

Describe how beta-hCG pregnancy test is done

Answer 26

urine is added to test tube coated with antibody against beta-hCG, then latex particles coated with beta-hCG antigen is added.

If pregnant, high beta-hCG in the urine will deplete antibody in test tube, so that addition of latex particles will NOT cause aggultination

If not-pregnant, addition of urine will not do anything to antibody coated in test tube, thus addition of latex particles will cause aggultination

Question 27

How is paclitaxel is used during coronary stent surgery?

Answer 27

paclitaxel inhibits mitosis by stabilizing microtubuels- prevents anaphase to occur

=> it prevents intimal hyperplasia

Question 28

What is confabulation? what disease is associated with it?

Answer 28

disturbed memory: talking about stories that never actually happened

seen in Wernicke-Korsakoff syndrom
: not only anterograde amnesia (retrograde is also seen but anterograde is more common) is seen, fabricated/disturbed memory problem is also seen in this disease

Question 29

breast mass decreased with size after delivery: diagnosis?

Answer 29

fibroadenoma

Question 30

chest X-ray finding in aortic dissection?

Answer 30

mediastinal widening and abnormal heart contour

• dissected aorta gets messy

Question 31

chest X-ray finding in pleural effusion?

Answer 31

blunting of costvertebral space

: water feels the bottom first

Question 32

leucine zipper dimer is characteristic functional unit of what protein?

Answer 32

transcription factor

leucine zipper dimers contain alpha helices that have DNA binding domain

Question 33

First reaction of de-novo pyrimidine synthesis? what enzyme? where in the cell does it occur?

Answer 33

CO2 + glutamate -> carbamoyl phosphate
mediated by carbamoyl phosphate synthase II (CPSII)

occurs in cytosol

Question 34

What is underlying physiology of atrophy of other three parathyroid glands in parathyroid adenoma?

Answer 34

negative feedback due to high Ca2+

Question 35

What is pressure atrophy?

Answer 35

mass COMPRESSING (thus pressure) the structure, limiting blood flow, causing atrophy

Question 36

dissection between right cruz and IVC in diaphragm increases risk for damaging what structure?

Answer 36

vagus trunks

Question 37

define

• vasogenic edema
• cytotoxic edema

Answer 37

• vasogenic edema: increased vascular permeability leads to liquid accumulation within interstitium
• cytotoxic edema: cellular injury leads to disruption of Na+/K+-ATPase, leading to accumulation of Na+, within the cell (so does liquid)