Marked Hypotonic Polyuria Resulting from Nephrogenic Diabetes Insipidus with Partial Sensitivity to Vasopressin*

We studied two women with severe hypotonic polyuria whose symptoms dated from infancy. We eliminated the possibility of central diabetes insipidus (DI) and primary polydipsia, and established the presence of nephrogenic DI on the basis of: 1) the interrelationships between plasma osmolality, urine osmolality, and urinary AVP; and 2) impaired antidiuretic responses to AVP and 1 deamino-8-D-arginine vasopressin. Though 25-50 times as resistant to 1 deamino-8-D-arginine vasopressin nasal spray as patients with central DI, these patients could be treated effectively with large doses of the nasal spray. One patient has been so treated for more than a year with dramatic improvement in her polydipsia, polyuria, and sense of well-being.