EVALUATION AND MANAGEMENT OF DIABETES-INSIPIDUS

Diabetes insipidus is an uncommon condition characterized by polyuria and polydipsia. The symptoms and biochemical changes of this condition result from either a lack of antidiuretic hormone or renal insensitiv ity to its effect. Failure to produce or release antidiuretic hormone may result from cranial pathology, including trauma and surgery. The r enal insensitivity to antidiuretic hormone that occurs in patients wit h nephrogenic diabetes insipidus may be caused by genetic factors, dru gs (especially lithium) or specific disease processes. Patients may co mpensate for polyuria and nocturia by excessive water intake but show marked decreases in urine specific gravity and osmolality. Patients wi th severe and uncompensated symptoms develop marked dehydration, neuro logic symptoms and encephalopathy. The water deprivation test is usefu l in diagnosing diabetes insipidus and in differentiating neurogenic f rom nephrogenic cases. Neurogenic diabetes insipidus may respond to na sal administration of desmopressin. Nephrogenic diabetes insipidus req uires good hydration and monitoring of body chemistry. Thiazides and a miloride may relieve symptoms.