Successful long-term treatment of congenital nephrogenic diabetes insipidus in a dog.

A two-year-old intact male shiba inu dog with excessive polyuria and polydipsia (PU-PD) was diagnosed as having congenital nephrogenic diabetes insipidus based on clinical findings, the results of urinalysis, blood examinations, a modified water deprivation test and a low dose dexamethasone suppression test. The owner was advised to provide adequate access to drinking water, and treatment with a low dose of hydrochlorothiazide (2 mg/kg, twice daily) together with a low sodium diet was initiated. As a result, the daily water intake decreased significantly from 6500 to 7500 ml/day (800 to 980 ml/kg/day) to 1400 to 1900 ml/day (170 to 230 ml/kg/day) and the clinical signs associated with the PU-PD and dehydration improved over the following two years.