Lithium-induced sinus node dysfunction

Area of Science:

• Cardiology
• Pharmacology
• Neurology

Background:

• Lithium carbonate is a mood stabilizer frequently prescribed for bipolar disorder.
• Potential adverse effects of lithium carbonate include cardiac and neurological toxicity.
• Sinus node dysfunction is a recognized but often asymptomatic complication of lithium treatment.

Observation:

• A 74-year-old woman on lithium carbonate developed symptomatic sinus node dysfunction and central nervous system toxicity.
• These symptoms resolved after discontinuing lithium carbonate, with a decrease in serum lithium levels from 2 to 1.27 mEq/L.
• Literature review indicates sinus node abnormalities associated with lithium can occur at both therapeutic and toxic levels.

Findings:

• Sinus node abnormalities associated with lithium carbonate treatment are frequently asymptomatic.
• These cardiac rhythm disturbances are typically completely reversible upon lithium discontinuation.
• Both therapeutic and toxic serum lithium levels can be associated with sinus node dysfunction.

Implications:

• Regular pulse monitoring is crucial for all patients receiving lithium carbonate.
• Prompt discontinuation of lithium is recommended if severe bradycardia or other arrhythmias develop.
• Awareness of potential cardiac effects is essential for safe lithium therapy management.