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Refeeding syndrome — USMLE Step 3 MCQ

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HardInternal Medicine (chronic management)Refeeding syndromeUSMLE Step 3

A 44-year-old man with severe alcohol use disorder and poor intake is admitted for malnutrition. Two days after starting tube feeds, he develops weakness and confusion. Phosphate is 1.0 mg/dL, potassium is 3.0 mEq/L, and magnesium is low. Which of the following is the most likely explanation for this patient's findings?

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Correct answer: C — Insulin-mediated intracellular electrolyte shifts after carbohydrate reintroduction

Refeeding syndrome occurs when carbohydrate reintroduction triggers insulin release, driving phosphate, potassium, and magnesium into cells.

Reference: ASPEN consensus recommendations on refeeding syndrome