Characteristics of deaths related to lithium toxicity in Australia, 2000-2024.

Objectives: To determine: (1) the characteristics, clinical presentation and circumstances of death for deaths related to lithium toxicity in Australia, 2000-2024; (2) the toxicology of cases; and (3) the major autopsy findings.

Methods: A retrospective study of all cases of death aged ⩾15 years associated with lithium toxicity in Australia, 2000-2024, retrieved from the National Coronial Information System.

Results: We identified 93 cases, with a mean age of 48.7 years (range, 18-89), 12% being aged under 30 years and 51% being male. A diagnosis of bipolar disorder was documented in 52%, with 28% having a documented psychotic disorder. The circumstances of death were unintentional toxicity (58%), intentional toxicity (23%) and undetermined intent (19%). The median blood lithium concentration was 0.68 mmol/L (range, 0.01-17.3). Concentrations were higher for ante-mortem versus post-mortem samples (2.3 vs 0.5 mmol/L), intentional overdose versus unintentional (2.2 vs 0.5 mmol/L) and cases in which lithium was the sole drug detected versus multiple drugs (2.1 vs 0.6 mmol/L). Other drugs were present in the majority (87%), most commonly antipsychotics (67%) and antidepressants (57%). Cardiomegaly was diagnosed in 22% and nephro/arteriosclerosis in 26%.

Discussion: Toxicity remains a rare event compared to exposure to lithium, with intentional cases comprising a fifth of the series. Deaths were not the sole preserve of the middle-aged or elderly.