What is the appropriate management of a patient with suspected lithium toxicity?

Management of Lithium Toxicity

Immediately discontinue lithium and assess severity based on clinical symptoms rather than serum level alone, as patients with chronic toxicity require more aggressive intervention than those with acute overdose, even at similar serum concentrations. 1, 2

Initial Assessment and Stabilization

Determine Type of Toxicity

• Acute toxicity (single overdose): Often presents with milder symptoms despite potentially lethal serum levels (>3.5 mEq/L), and patients frequently recover without hemodialysis 2
• Chronic toxicity (during maintenance therapy): Presents with more severe neurologic and cardiovascular symptoms at lower serum levels and requires more aggressive treatment 2, 3

Immediate Interventions

• Stop lithium immediately and do not resume until toxicity resolves 1, 4
• Check serum lithium level, renal function (creatinine, BUN, GFR), and electrolytes (particularly sodium) 5, 3
• Assess for precipitating factors: dehydration, sodium depletion, renal impairment, or concurrent NSAIDs/diuretics 5, 3

Severity-Based Treatment Algorithm

Mild Toxicity (Early symptoms: tremor, nausea, diarrhea)

• Cessation or dose reduction alone is usually sufficient 1, 6
• Resume treatment at lower dose after 24-48 hours if symptoms resolve 1
• Correct fluid and electrolyte imbalances 1, 3

Moderate to Severe Toxicity (Confusion, ataxia, seizures, cardiac arrhythmias, coma)

Gastric decontamination:

• Perform gastric lavage if presentation is within 1-2 hours of acute ingestion 1, 6
• Do NOT use activated charcoal - lithium is not bound by it 7

Enhance elimination:

• Hemodialysis is the most effective and rapid method for removing lithium and should be initiated for: 1, 6, 3, 4
  • Severe neurologic symptoms (seizures, altered mental status, coma) with any elevated lithium level 2, 3
  • Serum lithium >4.0 mEq/L in acute toxicity with symptoms 2
  • Serum lithium >2.5 mEq/L in chronic toxicity with moderate-severe symptoms 3
  • Renal insufficiency preventing adequate lithium clearance 3, 8

Critical hemodialysis considerations:

• Continue dialysis long enough to maintain serum lithium <1.0 mEq/L after redistribution from intracellular stores 3
• Expect rebound elevation as intracellular lithium equilibrates with extracellular fluid; prolonged or repeated dialysis may be necessary 8
• Peritoneal dialysis is less effective but acceptable if hemodialysis unavailable 6, 3, 4

Adjunctive measures:

• Maintain high-normal sodium levels (sodium administration may help remove intracellular lithium), but avoid sodium overloading which can cause hypernatremia 6, 3, 4
• Correct fluid and electrolyte imbalances carefully 1, 3
• Urea, mannitol, and aminophylline can increase lithium excretion but are less effective than dialysis 1

Supportive Care

• Monitor for complications: cardiac arrhythmias, acute renal failure (potentially reversible with treatment), neurologic sequelae 3, 8
• Provide infection prophylaxis and regular chest X-rays 1
• Ensure adequate respiratory support 1
• Serial monitoring of lithium levels, renal function, and electrolytes until complete resolution 3, 8

Common Pitfalls

• Do not rely solely on serum lithium level to determine need for hemodialysis in chronic toxicity - clinical severity is more important 2, 3
• Avoid aggressive sodium chloride infusion as it has no specific effect on lithium excretion and can cause dangerous hypernatremia 3, 4
• Do not underestimate chronic toxicity - patients on maintenance therapy with modest elevations can have severe symptoms and permanent sequelae 2, 3
• Recognize that renal insufficiency may persist after recovery, particularly if chronic nephropathy was present 3, 8