The effect of decontamination and elimination in large acute lithium overdoses

Acute lithium ingestion rarely results in neurotoxicity, except in larger ingestions, in which persistently high concentrations increase distribution into the brain. We investigated large acute ingestions of lithium and the effect of interventions.

This was a retrospective review of 18 patients with acute lithium overdoses >25 g over 17 years. Data were collected on neurotoxicity, treatments and serum lithium concentrations. Outcomes included neurotoxicity, area under the curve, and time until serum lithium concentration decreased <1.0 mmol/L.

The median reported lithium dose was 46 g (range 25.5-95 g). Two late presenting patients developed neurotoxicity. All patients had intravenous fluids, four received continuous kidney replacement therapy, and three whole bowel irrigation. In patients treated with intravenous fluids alone there was a significant association between dose and time until concentration decreases <1.0 mmol/L (n = 9; R² = 0.75; P = 0.002) and between dose and area under the curve (n = 10; R² = 0.68; P = 0.003). Three patients given whole bowel irrigation 4-9 h post-ingestion had lower area under the curve (54 mmol/L*h, 62 mmol/L*h, 155 mmol/L*h) compared to those given intravenous fluids alone ingesting similar doses (63 mmol/L*h, 199 mmol/L*h, 294 mmol/L*h). Continuous kidney replacement therapy increased lithium clearance.

Large acute lithium overdoses result in persistent measurable lithium concentrations and higher area under the curve, which increases with dose ingested, potentially increasing risk of neurotoxicity. Whole bowel irrigation reduced area under the curve, even when administered >4 h post-ingestion.

Whole bowel irrigation appears to reduce lithium burden and potential neurotoxicity in patients with large acute lithium overdoses.