Idiopathic Hypothalamic Dysfunction with Precocious Puberty and Adipsic Hypernatremia First Presenting in Adolescence

Background: Idiopathic hypothalamic dysfunction is a rare syndrome that has been described in young children. This syndrome is characterized by a disturbance of thirst regulation with hypernatremia, hyperosmolarity, and altered hypothalamic function.Patient report: At age 6 years the reported patients presented with precocious puberty, by age 12 years she had hypernatremia presumed secondary to central diabetes insipidus and was treated with DDAVP, and at age 14 was identified to have hyperprolactinemia. At age 19 she presented with serum sodium of 185 mg/dl, during an episode of illness associated with dehydration. After hydration, her sodium remained elevated. Arginine vasopressin was measurable but inappropriate to serum sodium, while urinary cyclic AMP response to vasopressin was appropriate.Conclusions: This is the first case of precocious puberty identified in association with the more classic features of idiopathic hypothalamic dysfunction, including later-onset hypernatremia, poor thermoregulatory function, obesity, and hyperprolactinemia.