Essential hypernatremia: disordered thirst and blood pressure control.

A 24 year old man developed partial central diabetes insipidus with impaired thirst and an elevated osmotic threshold to the release of arginine vasopressin (AVP). Plasma AVP was present in inappropriately small concentrations despite severe hyperosmolality. In addition, marked hypertension accompanied this disorder and all abnormalities, including the hypertension, responded to 1-desamino-8-D-arginine vasopressin therapy. Several lines of evidence suggest this disorder may be a disturbance of hypothalamic function.