Self-poisoning and therapeutic intoxication with lithium

Area of Science:

• Nephrology
• Clinical Toxicology
• Pharmacology

Background:

• Lithium is a common mood stabilizer, but overdose can lead to serious toxicity.
• Distinguishing between therapeutic intoxication and deliberate self-poisoning is important for management.
• Previous studies have not fully elucidated the differences in toxicity profiles between these two scenarios.

Purpose of the Study:

• To compare the clinical features and outcomes of lithium overdose from therapeutic intoxication versus deliberate self-poisoning.
• To identify factors predicting lithium toxicity in patients admitted for overdose.
• To inform treatment strategies for lithium overdose.

Main Methods:

• Retrospective analysis of 68 admissions for lithium overdose over 16 years.
• Categorization of admissions into therapeutic intoxication (25 cases) and deliberate self-poisoning (43 cases).
• Comparison of peak serum lithium concentrations, clinical manifestations (e.g., diabetes insipidus, renal failure), and laboratory parameters (urea, bicarbonate, lithium clearance).

Main Results:

• Therapeutic intoxication was associated with higher mean plasma urea and lower bicarbonate levels compared to self-poisoning.
• Despite similar peak serum lithium concentrations above the therapeutic range, toxicity was more frequent in therapeutic intoxication (22/22) than in self-poisoning (3/22).
• Longer serum lithium half-life was observed in therapeutic intoxication cases.

Conclusions:

• Therapeutic lithium intoxication presents with distinct biochemical derangements and a higher risk of toxicity compared to self-poisoning.
• Increased sodium excretion enhances renal lithium clearance, suggesting saline diuresis and frusemide as potential treatments.
• Hemodialysis is essential for renal failure and may be indicated for very high or rapidly rising serum lithium levels.