Lithium Toxicity

Key Features

• Occurs at serum lithium levels > 2 mEq/L

• Sodium loss (from diarrhea, diuretics, perspiration) results in elevated lithium levels

• Toxicity is more severe in the elderly

Clinical Findings

• Diarrhea, vomiting

• Tremors, marked weakness, confusion

• Dysarthria, ataxia, vertigo, choreoathetosis, hyperreflexia

• Rigidity, lack of coordination

• Myoclonus, seizures, opisthotonos, coma

Diagnosis

• Serum lithium levels confirm the diagnosis

Treatment

• Induced emesis and gastric lavage for massive ingestions or levels > 2.5 mEq/L

• Osmotic or saline diuresis in patients with normal kidney function

• Urinary alkalinization with sodium bicarbonate or acetazolamide

• Aminophylline potentiates the diuretic effect by increasing the clearance of lithium

• Hemodialysis should be considered when blood lithium levels are > 2.5 mEq/L