Lithium intoxication. (Report of 23 cases and review of 100 cases from the literature).

Twenty-three patients were studied, 21 of whom developed intoxication during maintenance therapy with a lithium dosage which had been unchanged for months to years. Toxic effects on brain, heart and kidneys were found and the severity of lithium intoxication seemed to depend on at least three factors: the height of the serum lithium concentration (SLi), the duration of lithium intoxication and individual tolerance. Disorders of water and electrolyte metabolism preceded lithium intoxication in the majority of the patients. Water loss due to impaired renal concentrating ability seemed to be a major predisposing factor. Renal insufficiency was apparent in 17 of the patients on admission and five of these did not regain normal renal function. In seven patients, renal biopsy showed abnormalities which suggest that a chronic nephropathy, possibly caused by lithium, might be another predisposing factor. Treatment with sodium chloride infusion had no specific effect on lithium excretion and led to hypernatraemia in some patients and is therefore not recommended. Hemodialysis is the most effective method available for removing the lithium ion from intoxicated patients. Hemodialysis should be carried out long enough to secure a SLi of less than 1 mmol/l after redistribution of lithium in the body. Treatment by peritoneal dialysis is appropriate only if hemodialysis facilities are unavailable. Lithium intoxication is a serious condition. Of the 23 patients reported, two died and two developed persisting neurological sequelae. The best way to prevent lithium intoxication is to control the serum concentration and to assess renal function and renal concentrating ability regularly during therapy.