USMLE Rx: Week of 12/12/16

Question 1

The direct pathway through the basal ganglia _____________ movement.

Answer 1

facilitates

Question 2

Trace the direct pathway through the basal ganglia.

Answer 2

Stimulating D1 receptors on the striatum stimulates the striatum to release GABA onto the GPi. The GPi normally inhibits thalamic nuclei. Inhibiting the GPi thus stimulates the thalamus, facilitating movement.

Question 3

Trace the indirect pathway through the basal ganglia.

Answer 3

Stimulating D2 receptors on the striatum inhibits it.

The striatum normally inhibits the GPe, so activating D2 receptors on the striatum un-inhibits the GPe.

The GPe inhibits the STN, so activating D2 receptors inhibits the STN.

The STN normally activates the GPi. So activating D2 receptors inhibits the striatum, activates the GPe, inhibits the STN, and activates the GPi.

The GPi normally inhibits movement, so the indirect pathway stops the inhibition of the GPi.

Question 4

Which antiarrhythmic can decrease the clearance of digoxin?

Answer 4

Quinidine

Think of the prom QueeN with DJ foxglove in her hotel room.

Question 5

Which immunosuppressants can cause nephrotoxicity?

Answer 5

Cyclosporine and tacrolimus

Question 6

Clinically, what is the best way to distinguish Wilms tumor from nephroblastoma?

Answer 6

Wilms tumor is one-sided, while nephroblastoma can cross the midline.

(Wilms = Wun-sided; nephroblastoma blasts across the midline.)

Question 7

What gene is commonly mutated in the childhood abdominal mass that crosses midline? What about in the one that doesn’t cross midline?

Answer 7

Crosses midline = nephroblastoma = N-myc

One-side = Wilms = WT1

Question 8

True or false: nephroblastoma is a malignancy of the distal tubule epithelium.

Answer 8

False. It is of the adrenal medulla (“Your NEPHROns get BLASTed with catecholamines.”)

Question 9

You prescribe a medication meant to help PUD in an adult female, but then you end up in front of your hospital’s M&M the next month for not asking if she was pregnant. What medication did you prescribe?

Answer 9

Misoprostol; this activates prostaglandin receptors and thus induces more secretion of protective mucus, but it can induce uterine contractions and is absolutely contraindicated in pregnant women.

Question 10

What pattern of pain might be expected in a child with currant-jelly stool?

Answer 10

Intermittent, “colicky” pain (this being intussusception)

Question 11

In a genetic pedigree, which shape is male?

Answer 11

Square (think of how men are stubborn and women –when pregnant –have ROUND bellies)

Question 12

Bisoprolol is a ___________ agent.

Answer 12

B1-selective (just like the name B1soprolol)

Question 13

Which kind of antihypertensive should you not prescribe to someone with lung disease and cyanosis?

Answer 13

Nonselective beta-blockers

Question 14

Nadolol is a _______________ agent.

Answer 14

nonselective beta-blocker (“Do you care which beta receptor you block?” “NA, I DO aLL.”)

Question 15

Which embryologic structures give rise to the thymus?

Answer 15

The third and fourth branchial pouches.

Think of this: you know that CATCH-22 is the mnemonic for DiGeorge, and Catch-22 took place in 43!

Question 16

Occlusion of the internal carotid artery would lead to ischemia in which area?

Answer 16

The watershed area between the anterior cerebral artery and the middle cerebral artery

Question 17

Increased salivary flow rate will result in increased concentration of which cation?

Answer 17

Na

Question 18

There are two types of Ehlers-Danlos syndrome. Which is more common?

Answer 18

The classical type that just affects joints is type V collagen, while the vascular types (resulting in lots of bruises) affects type III collagen.

Question 19

The left supraclavicular node (Virchow’s node) is a finding of which cancer?

Answer 19

Adenocarcinoma of the stomach

Question 20

Those with hepatic encephalopathy will usually have ___________ levels of alpha-ketoglutarate.

Answer 20

decreased (because it’s used to absorb ammonia)

Question 21

CA-19-9 and _____________ are serum indicators of pancreatic adenocarcinoma.

Answer 21

carcinoembryonic antigen