Clinical insights into adipsic diabetes insipidus: a large case series

Objective Adipsic diabetes insipidus (DI) causes significant hypernatraemia. Morbidity and mortality data for patients with adipsic DI have been previously published as single case reports, rather than as formal trials or case series from units with established management protocols. Our objective was to describe morbidity and mortality in patients with adipsic DI attending a tertiary referral centre, representing the largest reported series of adipsic DI, and to suggest management protocols for such patients, based on our extensive experience of this condition. Design Arginine vasopressin (AVP) responses to hypotension were recorded during trimetaphan infusion. Sleep abnormalities were identified using overnight oximetry or polysomnography. Case-note analysis defined other clinical abnormalities including seizures and thrombotic episodes. Important clinical points for the management of these patients are highlighted. Patients Thirteen patients with adipsic DI defined by thirst and plasma AVP responses to hypertonic saline infusion. Results All patients had absent AVP and thirst responses to osmotic stimulation, with subnormal water intake. Five patients had absent AVP responses to hypotension; the remainder had normal responses. Eight patients were obese [body mass index (BMI) > 30 kg/m(2)], and three were overweight (BMI > 25 kg/m(2)). Seven patients had sleep apnoea, of whom three died at 36 years or younger. Four patients developed venous thrombosis during episodes of hypernatraemia. Two patients had thermoregulatory dysfunction and seven patients had seizure activity. Conclusion Adipsic DI is associated with significant morbidity and mortality. Physicians should be aware of associated, treatable hypothalamic abnormalities such as obesity, sleep apnoea, seizures and thermoregulatory disorders when managing adipsic DI.