Postoperative diabetes insipidus associated with pituitary apoplexy during pregnancy

Pituitary apoplexy during pregnancy is so rare that only 15 cases (12 pituitary adenomas, 2 lymphocytic neurohypophysitis, and 1 normal pituitary gland) have been published to date. Here, we report the case of a pregnant woman presenting with pituitary apoplexy from a nonfunctioning pituitary adenoma and provide a possible mechanism and management option for postoperative diabetes insipidus (DI).

A 26-year-old woman presented with sudden onset of headache and bitemporal hemianopsia in the 26th week of her first pregnancy. Magnetic resonance imaging clearly revealed an 18 mm pituitary mass with a fluid-fluid level component displacing the optic chiasma upward. Endonasal endoscopic transsphenoidal surgery was successfully carried out 7 days after the onset of symptoms. DI became apparent immediately after the operation and was not controllable by arginine vasopressin (AVP) but by 1-desamino-8-D-arginine vasopressin (DDAVP) instead. This finding suggests an association between DI and vasopressinase secretion from the placenta, because vasopressinase can degrade AVP but not DDAVP. DI had diminished by the time the patient delivered a healthy girl at the 40th week of gestation.

Postoperative DI associated with pituitary apoplexy during pregnancy should be treated by DDAVP, which is not affected by placental vasopressinase secretion.