[Essential hypernatremia with hypovolemia caused by hypodipsia and partial diabetes insipidus].

The authors report the case of 13 year old girl presenting with chronic hypernatremia. This case should be considered as either neurogenic or essential hypernatremia. Partial diabetes insipidus and hypodipsia hypernatremia. Partial diabetes insipidus and hypodipsia are the cause of chronic hypovolemia and a new homeostasis with an exceptionally high level of sodium (isoosmotic point 154 mEq/l). No cause was found and in particular, the search for a cerebral disease was until now proved negative.