RESUMO
OBJECTIVE: To illuminate the natural history of prolonged nephrogenic diabetes insipidus after discontinuation of lithium carbonate treatment and to assess the response to therapy with desmopressin acetate and triamterene-hydrochlorothiazide. METHODS: We analyzed sequential determinations of serum and urine osmolality, plasma arginine vasopressin, serum sodium, blood urea nitrogen, calcium, ionized calcium, parathyroid hormone, and 24-hour urine volume during a period of 57 months in a 67-year-old woman. RESULTS: Our patient experienced persistent polyuria in conjunction with having repeated serum osmolalities between 300 and 323 mOsm/kg and urine osmolalities between 130 and 208 mOsm/kg. Concomitant plasma arginine vasopressin levels were as high as 12.0 pg/mL, consistent with the diagnosis of nephrogenic diabetes insipidus. Administration of triamterene-hydrochlorothiazide reduced 24-hour urine volume and serum osmolality while increasing urine osmolality. Desmopressin acetate exhibited no effect. CONCLUSION: In this report, we describe the eighth documented case of persistent nephrogenic diabetes insipidus, lasting 57 months after cessation of lithium therapy, and demonstrate a palliative effect of triamterene-hydrochlorothiazide.