What is the management of lithium toxicity?

Management of Lithium Toxicity

The management of lithium toxicity requires immediate discontinuation of lithium, supportive care, and in severe cases, hemodialysis to rapidly remove lithium from the body. 1

Types of Lithium Toxicity

Lithium toxicity can present in three patterns:

• Acute toxicity: Single large ingestion in a lithium-naïve patient
• Acute-on-chronic toxicity: Overdose in a patient on maintenance lithium
• Chronic toxicity: Most common form, usually unintentional, occurs when lithium intake exceeds elimination 2

Clinical Presentation

Lithium toxicity can affect multiple organ systems with severity correlating to serum levels:

• Mild toxicity (1.5-2.0 mmol/L): Nausea, vomiting, tremor, drowsiness
• Moderate toxicity (2.0-2.5 mmol/L): Confusion, lethargy, muscle weakness, ataxia
• Severe toxicity (>2.5 mmol/L): Seizures, coma, cardiovascular collapse 3, 2

Notably, neurotoxicity can occur even at therapeutic levels in some patients, making clinical assessment crucial 4.

Management Algorithm

1. Immediate Interventions

• Discontinue lithium immediately 1
• Assess vital signs and stabilize if necessary
• Obtain serum lithium level urgently
• Evaluate renal function, electrolytes, and fluid status 3

2. Supportive Care

• Fluid resuscitation: Correct dehydration and electrolyte imbalances
• Monitor sodium levels closely as hypernatremia can reduce lithium elimination 5
• Gastric lavage for recent acute ingestions 1
• Correct fluid and electrolyte imbalances 1
• Ensure adequate respiratory function with regular monitoring 1

3. Indications for Hemodialysis

Hemodialysis is the most effective method for lithium removal in severe toxicity 6. Consider hemodialysis for:

• Serum lithium level >4.0 mmol/L
• Severe neurological symptoms regardless of level
• Significant renal impairment limiting lithium excretion
• Failure to respond to conservative management 2

4. Monitoring During Treatment

• Serial lithium levels until normalized
• Continuous neurological assessment
• Electroencephalogram (EEG) monitoring in cases of neurological symptoms 6
• Renal function tests to assess kidney damage 3

Prevention of Recurrence

After resolution of toxicity:

• Reassess need for lithium or consider alternative mood stabilizers
• If lithium is restarted:
  • Begin at lower dose
  • Monitor levels more frequently (twice weekly until stable)
  • Target lower therapeutic range (0.6-0.8 mmol/L) 3
• Educate patient about early symptoms of toxicity and importance of regular monitoring 3

Special Considerations

• Chronic lithium toxicity may require longer hospital stays due to persistent neurological deficits 2
• Cerebellar damage can persist after lithium levels normalize 2
• Pregnancy increases risk of toxicity due to physiological changes 3
• Elderly patients are at higher risk due to decreased renal clearance 3

Common Pitfalls

• Failure to recognize toxicity at "therapeutic" levels in vulnerable patients 4
• Inadequate monitoring of sodium levels during treatment 5
• Delayed hemodialysis in severe cases 6
• Premature discharge before complete neurological recovery
• Failure to identify and address the underlying cause of toxicity (e.g., medication interactions, renal impairment) 3

Remember that lithium has a narrow therapeutic window, and toxicity can occur at levels close to therapeutic concentrations, making vigilant monitoring essential 1, 7.