A case report of hypodipsic hypernatremia syndrome associated with suprasellar tumor.

A 20-year-old woman was diagnosed as hypodipsic hypernatremia syndrome in association with a variety of hypothalamic syndromes. Computed brain tomography disclosed a space occupying lesion over the region of the hypothalamus, lateral ventricle and paraventricles. Evaluation revealed defective osmoregulation of thirst and AVP release and hypothalamic syndrome. She showed no desire to drink at a plasma osmolality of above 320 mOsm/kg. Dissociation in the plasma vasopressin response to osmotic change and hemodynamic change was demonstrated in this patient. Treatment with a vasopressin analogue, desamino-D-arginine vasopressin and forced intake of water restored plasma osmolality and serum sodium levels to normal. In this case, selective osmoregulating dysfunction was presumably associated with pathologic conditions in or around the hypothalamus.