Abstract

 

42-year-old man was admitted to our outpatient clinic with polyuria (9-10 liters/day) and polydipsia for 6 months.

On further questioning he had a history of bipolar affective disorder and he was taking lithium carbonate 1500 mg

daily. His plasma osmolality (298 mOsm/kg) and plasma Na level (148 mmol/L) were high, urine osmolality (160

mOsm/kg) and urine density (1005) were low. Plasma lithium level was in therapeutic range [0.76 (0.6-1.2

mmol/L)]. All these clinical and laboratory parameters, and water deprivation test results were relevant to

nephrogenic diabetes insipidus. Lithium therapy was discontinued, valproic acid and amiloride therapy were

initiated. Clinical and laboratory features improved and urine volume decreased after the new therapeutic regime.

We reported a usual but a very important complication of lithium therapy. In patients taking lithium therapy and

presenting with poliuria, the diagnosis of nephrogenic diabetes insipidus must be considered.

Key Words: Lithium, Nephrogenic Diabetes Insipidus.