[Analysis of the poisonings by lithium in a department of internal medicine].

Introduction: Lithium salts have been mainly used in the treatment of bipolar disorder. Because of its narrow therapeutic range, and several well characterised adverse effects, serum lithium levels must be monitored regularly in patients given lithium treatment in order to prevent intoxication.

Objective: To describe the clinic and toxic characteristics in inpatients at our Clinic Toxicologic Unit.

Material and methods: Descriptive and retrospective study of lithium intoxications in 150 inpatients between 2003 and 2006. Patients were classified based on their neuropsychiathric symptom profile and serum lithium levels.

Results: Sixteen of 150 inpatients had lithium intoxication: 58.3% women and 43.8% men; 49.19% +/- 18.49% years old. Lithium was used as treatment of bipolar disorder in 87.5% of cases. The most frequent cause of intoxication was attempted suicide. Using neuropsychiatric parametres, intoxication was moderate in 50% of cases, and mild in 25% and severe or very severe in 25%. Using serum lithium levels, intoxication was very severe in 31.35%, severe in 25%, and slight-moderate in 43.7%. Conservative measures were used as the most frequent treatment (50%), and haemodialfiltration was needed in 37.5%. Mean stay was 4,8 days in acute intoxication, and 11.2 days in chronic. Sequelaes were found in two patients (ataxia). Death was not present.

Conclusions: Lithium intoxications can involve severe complications, even death. Narrow control is encouraged in polymedicated and elderly patients, and in concommitant treatment with antidepressant and neuroleptics.