Lithium toxicity

Three patterns: • Acute (lithium-naïve overdose): high level, low total body burden, mostly GI features early; CNS toxicity later as it distributes. • Chronic: established therapy + precipitant (dehydration, NSAIDs, ACEi/ARB, diuretics, infection, AKI); CNS features dominate at lower levels. • Acute-on-chronic: worst — high body burden plus acute load. Features: tremor, hyperreflexia, ataxia, dysarthria, confusion, myoclonus, seizures, coma; T-wave changes; nephrogenic DI; SILENT (Syndrome of Irreversible Lithium-Effectuated NeuroToxicity). ABCDE; bloods: lithium level (12 h post-dose if chronic), U&E, creatinine, eGFR, calcium, glucose, TFTs, paracetamol/salicylate, ECG.