Diabetes insipidus.

Water balance is precisely regulated by vasopressin, thirst and the kidneys; plasma osmolality is maintained within a narrow range, despite large variations in normal water intake and loss. Disruption of these finely balanced mechanisms is common, however, and can be precipitated by various disease states. Diabetes insipidus is a disease process with several underlying pathogenic mechanisms--all ultimately resulting in excretion of large volumes of dilute urine. This review will discuss the pathophysiology, diagnosis and treatment of diabetes insipidus, with emphasis on disorders of osmoregulation following neurosurgery of the pituitary and hypothalamus.