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Lithium toxicity — USMLE Step 3 MCQ

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HardPsychiatry (outpatient management)Lithium toxicityUSMLE Step 3

A patient taking lithium develops nausea, coarse tremor, ataxia and confusion after hydrochlorothiazide was added. Creatinine is 1.6 mg/dL and lithium concentration is 2.4 mEq/L. What is the immediate management?

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Correct answer: C — Stop lithium, give IV fluids and arrange urgent specialty assessment

This is symptomatic lithium toxicity, worsened by thiazide-associated reduced lithium clearance. A provides immediate mitigation and specialist evaluation. B through E worsen or ignore toxicity.

Reference: American Psychiatric Association, Bipolar Disorder Practice Guideline: https://www.psychiatry.org/psychiatrists/practice/clinical-practice-guidelines