Can lithium cause pulmonary toxicity?

Lithium and Pulmonary Toxicity

Yes, lithium can cause pulmonary toxicity, though it is rare compared to other adverse effects. Several case reports document pulmonary complications associated with lithium therapy, including acute respiratory distress syndrome (ARDS) and pulmonary hypertension.

Documented Pulmonary Complications of Lithium

• Acute respiratory distress syndrome (ARDS) has been reported in cases of severe lithium toxicity with serum levels typically above 3 mmol/L 1
• Acute pulmonary edema secondary to myocardial depression has been documented in lithium intoxication 2
• Pulmonary hypertension has been reported during long-term lithium therapy (after 6 years of treatment) 3

Risk Factors and Mechanisms

• Pulmonary toxicity is most commonly associated with severe lithium intoxication rather than therapeutic use 1
• The mechanism appears to be multifactorial:
  • Possible myocardial depression leading to pulmonary edema 2
  • Direct toxic effects on lung tissue 1
  • Long-term effects potentially leading to pulmonary hypertension 3

Clinical Presentation

• Respiratory symptoms typically occur alongside other signs of lithium toxicity 1
• Presenting features may include:
  • Dyspnea and respiratory failure 1
  • Bilateral pulmonary edema visible on chest imaging 1
  • Hypoxemia requiring oxygen supplementation or mechanical ventilation 1
  • Concurrent neurological symptoms (altered mental status, stupor) 1, 2

Management of Lithium-Associated Pulmonary Toxicity

• Immediate discontinuation of lithium therapy 1
• Hemodialysis to rapidly reduce lithium levels in severe cases 1
• Supportive respiratory care, which may include:
  • Oxygen supplementation 2
  • Mechanical ventilation in severe cases 1
  • Treatment of pulmonary edema with diuretics 2

Prevention of Lithium Toxicity

• Regular monitoring of serum lithium concentrations is essential, especially during initiation of therapy 4
• Temporarily suspend lithium during intercurrent illness, planned IV radiocontrast administration, bowel preparation, or prior to major surgery 4
• Be alert to early signs of lithium toxicity such as tremor, nausea, diarrhea, and polyuria-polydipsia 4
• Maintain therapeutic lithium levels between 0.6-1.0 mmol/L; levels >1.5 mmol/L may be toxic, and levels >2.0 mmol/L can cause permanent damage 5

Important Considerations

• While pulmonary toxicity is a documented complication of lithium therapy, it is much less common than neurological, renal, thyroid, and cardiac adverse effects 6
• The risk of pulmonary complications appears to increase significantly with lithium levels above 3 mmol/L 1, 2
• Recovery from pulmonary complications typically occurs with supportive care and reduction of lithium levels 1, 2

Clinicians should maintain vigilance for respiratory symptoms in patients on lithium therapy, particularly those with elevated serum levels or other signs of toxicity, as prompt recognition and management are essential to prevent serious complications.