Patterns of anti-diuretic function in diabetes insipidus caused by histiocytosis X.

Abstract

Abstract Eight children with histiocytosis X who had diabetes insipidus were tested for their ability to respond to water deprivation. Four children were examples of the classic absence of osmotic threshold and lack of urinary concentrating ability. Although 4 children had clinical signs of polyuria and polydipsia, their osmotic thresholds and urinary concentrating abilities after various periods of water deprivation indicated residual vasopressin activity (partial diabetes insipidus). The spectrum of functional impairment in this latter group of patients with partial diabetes insipidus includes patients with a decreased response to water deprivation, one of whom also demonstrated an increased threshold for antidiuretic function and one patient with a specific failure of osmotic receptors. During the period of observation, one patient progressed from partial to complete loss of function, and one child in the control group developed partial diabetes insipidus. The symptoms of polyuria and polydipsia must be taken as indicative of a significant but not necessarily total hypofunction of the water-conserving mechanism. In view of our experience with failure of the hypertonic saline infusion test and the simple 8 hour water-deprivation test to delineate the extent of damage, a more extensive evaluation of water metabolism in all patients having polyuria and polydipsia is recommended.