Lithium Toxicity — RACP Adult Medicine MCQ

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EasyNephrologyLithium ToxicityRACP Adult Medicine

A 60-year-old man on long-term lithium presents with tremor, confusion, and vomiting. His lithium level is 3.2 mmol/L (therapeutic 0.6–1.0). He has acute kidney injury with creatinine 350 μmol/L. What is the most likely causative drug?

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Correct answer: B — Lithium

Severe lithium toxicity (level >2.5 mmol/L) presents with neurological features (confusion, tremor, myoclonus, seizures) and GI symptoms. AKI reduces lithium clearance causing accumulation. Chronic toxicity can occur at lower levels. Management includes aggressive IV saline and haemodialysis for severe cases (level >4.0, or >2.5 with neurological symptoms or AKI).

Reference: AMH – 2025 – Lithium; eTG Psychotropic 2024