Antidiuretic function in Sheehan's syndrome

Twenty patients with postpartum hypopituitarism underwent a dehydration test followed by the administration of synthetic arginine-vasopressin (DDAVP; desmopressin). Panhypopituitarism was confirmed by hormonal assays in the basal state and after stimulation with combined luteinising hormone releasing hormone-thyrotrophin releasing hormone-insulin. All the patients were given replacement therapy with hydrocortisone and thyroid hormones. Results were compared with those in 12 normal women. Urinary concentrating ability was diminished in the patients as compared with the controls (maximum urine osmolality 688 (SEM 23) mmol (mosmol)/kg in the patients v 967 (SEM 29) mmol/kg in the controls). Also the change in urine osmolality after administration of desmopressin was greater in the patients (+9.55 (SEM 1.98)% in the patients v 2.49 (SEM 0.96)% in the controls). Partial diabetes insipidus is apparently common in Sheehan's syndrome. This association should be borne in mind when managing these patients, especially those in acute failure.