Hard Question #4

[leviathan]

Here's a Step 1 practice question, which I personally think has a ridiculous answer but maybe it's just me. Let's see!

 

A demented 83-year-old man is brought to the emergency department from a nursing home because of generalized edema and oliguria. Vital signs are normal. Laboratory studies of serum show a creatinine of 2.1 mg/dL and BUN of 63 mg/dL. Which of the following is the most likely diagnosis?

 

A. Severe liver disease

B. Low protein intake

C. Acute tubular necrosis

D. Prostatic hyperplasia

E. Congestive heart failure

[thebouque]

So the increase in urea is greater than the increase in creatinine, which indicates a prerenal failure. Vital signs are normal.

Could be severe liver disease

Low protein intake wouldn't be acute

Acute tubular necrosis and prostatic hyperplasia aren't prerenal

Congestive heart failure: vitals wouldn't be normal

 

I go with A

[MarkSeve808]

A......?

 

 

Nice post!

[leviathan]

Were you guys thinking of hepatorenal syndrome for severe liver damage?

 

The answer given is D, prostatic hyperplasia. High BUN:creatinine ratios can occur in postrenal like this case (which I wasn't aware of) and pre-renal azotemia SUPERIMPOSED on renal disease, but not simple pre-renal failure. I thought the answer was CHF (you don't have to have abnormal vitals to have CHF), but apparently simple CHF would not alter the BUN:creatinine ratios?

 

I've never heard of that, and they didn't say whether the man had prior renal disease or not, so overall I just think this is an awfully written question. Apparently only 13% got it right.

[thebouque]

Were you guys thinking of hepatorenal syndrome for severe liver damage?

 

The answer given is D, prostatic hyperplasia. High BUN:creatinine ratios can occur in postrenal like this case (which I wasn't aware of) and pre-renal azotemia SUPERIMPOSED on renal disease, but not simple pre-renal failure. I thought the answer was CHF (you don't have to have abnormal vitals to have CHF), but apparently simple CHF would not alter the BUN:creatinine ratios?

 

I've never heard of that, and they didn't say whether the man had prior renal disease or not, so overall I just think this is an awfully written question. Apparently only 13% got it right.

 

I wasn't necessarily thinking about hepatorenal. Altered liver function could've caused ascites, volume contraction and therefore a prerenal failure.

 

But I got it wrong anyway lol. Thanks for posting!

[A-Stark]

This question is why the USMLE sucks (*crosses fingers* re: passing). I'll pull out my First Aid guide a bit later to find another hard question.

[CdnatWayne]

Which qbank is this from?