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Anorexia nervosa medical instability — USMLE Step 3 MCQ

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HardPediatricsAnorexia nervosa medical instabilityUSMLE Step 3

A 14-year-old girl with restrictive eating and compulsive exercise has lost 18% of body weight in 3 months. BMI is 16.2 kg/m², daytime pulse is 44/min, blood pressure is 86/48 mm Hg, potassium is 3.0 mEq/L, phosphorus is 2.1 mg/dL, and QTc is 492 milliseconds. She denies suicidality and requests outpatient treatment. Which disposition is most appropriate?

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Correct answer: A — Admit for cardiac monitoring, electrolyte correction, and supervised nutritional rehabilitation

The best answer is “Admit for cardiac monitoring, electrolyte correction, and supervised nutritional rehabilitation”. Severe bradycardia, hypotension, hypokalemia, hypophosphatemia, rapid weight loss, and QTc prolongation each support medical hospitalization. Initial care requires cardiac and electrolyte monitoring, cautious but adequately progressive nutrition, thiamine when indicated, and surveillance for refeeding shifts. Psychiatric and family-based treatment are essential, but this physiologic instability must be corrected in a medical setting first.

Reference: Society for Adolescent Health and Medicine: Medical Management of Restrictive Eating Disorders: https://pmc.ncbi.nlm.nih.gov/articles/PMC10864000/