Lithium Intoxication and Nephrogenic Diabetes Insipidus in a Bipolar Patient-Case Report

Nephrogenic diabetes insipidus has been reported to increase the risk for lithium intoxication. We report on a 52-year-old woman with bipolar disorder who had been treated with lithium regularly for twenty years. She had developed polyuria and polydipsia one year previously, and a depressive episode with psychotic features one month before this admission. She had not had a manic or a depressive episode for three years. Lithium was discontinued and supportive treatment was provided when lithium intoxication was diagnosed on the first day of hospitalization. Despite the disappearance of symptoms of intoxication on the 12th day of her 22 day hospitalization, she still suffered from polyuria, polydipsia, and mild cognitive impairment when she was discharged. This case report emphasizes the importance of early identification and treatment of nephrogenic diabetes insipidus and lithium intoxication in lithium-treated patients to prevent irreversible sequelae from a combination of these two conditions.