

NBME 20 Answers

nbme20/Block 4/Question#20

A 5-year-old boy is brought to the physician for a ...


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submitted by celeste(21),


medschul  Wouldn't Fanconi syndrome also cause hypokalemia though? +2  

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submitted by imgdoc(9),

You can cross out the top three answer choices, A,B,C. You wont be reabsorbing anything in the PCT in fanconi's syndrome. Looking at hypokalemia, hyponatremia, and hypophosphatemia now. Hypokalemia can't be correct because even though potassium is lost it will be reabsorbed at the later thick ascending loop and if that doesnt make sense, the body will adjust for low serum potassium but activating the H+/K+ pump on cells. It isn't hyponatremia because at the collecting duct principal cells, reabsorption will occur. This leaves hypophosphatemia as the correct and only answer choice.

imgdoc  by* +1  
larascon  Excellent explanation, thank you ! +  

 -2  upvote downvote
submitted by dontwanttofail(-2),

The answer is actually hypokalemia, according to NBME.

dontwanttofail  JK. Please ignore. The answer is hypophosphatemia +