lithium toxicity

pharmacology

  • Handling: Handled by the kidney exactly like Sodium.
  • Risk Factors: Dehydration, Hyponatraemia, Thiazides, ACEi/ARBs, NSAIDs (reduce clearance).

clinical presentation

  • Acute: GI predominant (Nausea, Vomiting, Diarrhoea). Delayed neuro symptoms.
  • Chronic: Neuro predominant (Tremor, Hyperreflexia, Ataxia, Confusion, Seizures). Occurs at lower levels.

management

1. decontamination

  • Activated Charcoal: Ineffective (does not bind metals).
  • Whole Bowel Irrigation (PEG): Consider for large acute ingestions (sustained release).

2. elimination

  • Fluid Resuscitation: Normal Saline. (Restoring GFR + Sodium load promotes excretion).
  • Haemodialysis: The definitive clearance method.
    • Indications:
      • Severe neurological impairment (coma, seizures).
      • Renal failure (cannot clear).
      • Levels: > 4.0 mmol/L (Acute) or > 2.5 mmol/L (Chronic).

SILENT syndrome

Syndrome of Irreversible Lithium-Effectuated NeuroToxicity. Permanent cerebellar sequelae (ataxia, dysarthria) after severe toxicity.