USMLE-Rx Step 1 Practice Q's

USMLE-Rx Step 1 Qmax Challenge #4091

Check out today’s Step 1 Qmax Question Challenge.

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USMLE-Rx Step 1 Qmax Challenge #4091A 70-year-old man complains of a long history of pain in his ankles, toes, and fingers. He has experienced intermittent acute attacks of exquisite pain every few months, followed by completely asymptomatic periods. In recent years, he has had near-constant discomfort at baseline, and now has permanent “swelling” in many of the joints of his fingers and toes. Joint fluid is aspirated, and the fluid is examined under polarized light (shown in the image). Treatment is initiated, and the patient’s uric acid levels gradually fall.

What is the mechanism of action of the best treatment?

A. Binds tubulin
B. Blocks formation of prostaglandins and thromboxane from arachidonic acid
C. Inhibits release of phospholipase A2
D. Inhibits xanthine oxidase
E. Selective, competitive angiotensin II receptor inhibition


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13 replies »

  1. D is the correct answer because we are dealing with ” in between” the attacks. During the attack Allopurinol could actually worsen the condition. So during the attack colchicine or NSAIDs would work. And believe it or not NSAIDs are preferred and now are the first line. Colchicine is good if patient has contraindication for NSAID like peptic ulcer disease.


  2. Thank you Silvia. And here is one more cool thing about the reason “big toe” is one of the most common joints affected. Yes you are right “location, location, location” because big toe is “cooler” and crystals love cool temperature and as soon as they find somewhere with “AC: Air Conditioning” they go there and start “relaxing and laying down”. Isn’t that cool?


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