Endocrine Abstracts

Introduction: The natural history of adipsic diabetes insipidus (ADI) is not completely understood. Isolated case reports suggest occasional recovery of adipsia. We present the follow up of a cohort of 12 patients with ADI.

Setting: National pituitary unit with interest in diabetes insipidus.

Methods: ADI was identified by demonstrating absent thirst and AVP responses to hypertonic saline infusion. Results 12 patients with ADI were identified (fivecraniopharyngioma, four ACOM aneurysm repair, one congenital, one neurosarcoidosis, and one prolactinoma). Three patients died. Six patients had permanent adipsic diabetes insipidus. Three patients had recovery of thirst, with a heterogenous pattern of recovery.

Case 1: A 41-year-old female with an intrasellar craniopharyngioma developed postoperative ADI with persistent hypernatremia (147–172 mmol/l). Two years postoperatively, she complained of thirst, and hypertonic saline infusion showed normal thirst but absent AVP responses, confirming recovery of thirst with persistent DI.

Case 2: A 29-year-old Caucasian had craniotomy and radiotherapy for craniopharyngioma which had previously presented with chronic headache and bitemporal hemianopia and developed ADI postoperatively. Eight years post-op, she presented with thirst, seizures and pNa of 112 mmol/l. Hypertonic saline infusion showed persistent DI but thirst responses typical of compulsive water drinking; she has had recurrent hyponatraemia since then.

Case 3: A 51-year-old gentleman developed ADI after clipping of an ACOM aneurysm and was treated with desmopressin and sliding fluid scale. 10 years post surgery; he sensed the return of thirst; repeated hypertonic saline infusion showed recovery of both thirst and AVP secretion. He is asymptomatic off desmopressin.

Conclusion: We report that three out of 12 patients with ADI recovered thirst after longstanding adipsia. The pattern of recovery was heterogenous and included complete recovery of ADI, recovery of adipsia only and conversion of adipsia to polydipsia. Both the mortality of 25% and the recovery rate of 25% should be considered during long-term surveillance.