What are the guidelines for managing lithium toxicity in patients taking lithium for mood stabilization?

Management of Lithium Toxicity

For severe lithium toxicity (serum levels ≥3.5 mEq/L with significant symptoms, or any level with cardiovascular compromise), hemodialysis is the treatment of choice and should be initiated urgently. 1

Immediate Assessment and Stabilization

When lithium toxicity is suspected, immediately:

• Discontinue lithium and assess severity based on clinical symptoms and serum lithium level 2
• Recognize that toxicity begins at 1.5 mEq/L and becomes serious at >2.0 mEq/L 3
• Understand that chronic toxicity presents with more severe symptoms than acute overdose, even at similar serum levels 4
• Check serum lithium level, electrolytes (especially potassium, magnesium, sodium), renal function (BUN, creatinine, GFR), and obtain ECG 1, 3

Clinical Presentation by Severity

Early/Mild toxicity includes tremor, nausea, diarrhea, and polyuria-polydipsia 1

Moderate to severe toxicity manifests with neurological symptoms (confusion, ataxia, seizures) and cardiovascular effects (arrhythmias, ECG changes, hypotension, bradycardia, AV block, myocardial dysfunction) 1, 5

Critical pitfall: Severity of symptoms does not always correlate with serum levels, particularly in chronic versus acute intoxication 1

Treatment Algorithm Based on Severity

Mild Toxicity

• Cessation or dose reduction alone is often sufficient 2, 6
• Resume treatment at lower dose after 24-48 hours if clinically appropriate 2
• Correct fluid and electrolyte imbalances 2

Moderate Toxicity

• Perform gastric lavage if recent acute ingestion 2, 6
• Aggressively correct fluid and electrolyte imbalances 2
• Maintain high-normal sodium levels to facilitate lithium removal from intracellular compartments 6
• Consider hemodialysis if symptoms progress despite conservative management 1

Severe Toxicity - Hemodialysis Indications

Hemodialysis is urgently indicated when:

• Serum lithium ≥3.5 mEq/L with significant neurological or cardiovascular symptoms 1
• Any lithium level with significant cardiovascular compromise (symptomatic bradycardia, advanced AV block, refractory hypotension) 1
• Severe symptoms (seizures, coma, oliguria) with any supratherapeutic level in chronic toxicity 4, 7
• Refractory toxicity despite conservative management 1

Important distinction: Patients with acute overdose may tolerate levels >3.5 mEq/L with mild symptoms and may not require hemodialysis, whereas chronic toxicity patients with severe symptoms at lower levels should receive hemodialysis 4

Hemodialysis Protocol

• Continue dialysis until lithium level <1.0 mEq/L after redistribution (generally 6-8 hours) 1
• Measure lithium level 4-6 hours post-dialysis to evaluate for rebound from tissue redistribution 1
• Hemodialysis is more effective than peritoneal dialysis for rapid lithium removal 6, 7

Management of Specific Complications

Arrhythmias

• Correct electrolytes, especially potassium and magnesium 1
• Initiate hemodialysis as primary treatment 1
• Avoid antiarrhythmic drugs that prolong QT interval (amiodarone, sotalol) if QT prolongation is present 1

Hypotension

• Administer intravenous fluids 1
• Use vasopressors such as norepinephrine if needed 1
• Initiate urgent hemodialysis if hypotension persists despite support 1

Prevention of Future Toxicity

After stabilization, identify and address precipitating factors:

• Evaluate for dehydration, medication interactions (especially NSAIDs), or renal impairment 1
• Temporarily suspend lithium during intercurrent illness, IV radiocontrast administration, bowel preparation, or prior to major surgery 1, 3
• Avoid concomitant NSAIDs which increase lithium levels 1, 3
• Maintain adequate hydration, especially during illness 1, 3
• Implement regular monitoring of lithium levels, electrolytes, and renal function 1
• During acute treatment phase, check serum lithium twice weekly until stabilized 3

Patient and Caregiver Education

• Educate patients and caregivers about early signs of toxicity (tremor, nausea, diarrhea, confusion) to allow rapid intervention 1, 2
• This is particularly critical in children and adolescents, as overdoses can be lethal 1
• Instruct patients to discontinue lithium and contact physician immediately if early symptoms occur 2

Long-term Sequelae

Persistent neurological deficits, particularly cerebellar signs (ataxia, dysarthria), can occur and greatly reduce quality of life 8, 5. These are more common after chronic toxicity than uncomplicated acute poisoning 5. Conservative prescribing and early recognition of toxicity are essential to prevent irreversible neurologic damage 8