SUN-407 A Clinical Lesson in Adipsic Diabetes Insipidus

Background: Adipsic diabetes insipidus (ADI) is a rare condition with approximately 100 reported cases word wide. Inpatient management can be challenging as patients are predisposed to dysnatremia during this time. Societal guidelines offer little guidance in management of this complex disease. Case: A 62-year-old woman with a history of acromegaly with transphenoidal resection more than 20 years ago, complicated by post-operative hypothyroidism, adrenal insufficiency and adipsic diabetes insipidus presented for admission for a planned cycle on of chemotherapy for her recently diagnosed diffuse large B-cell lymphoma. At admission her initial serum sodium was 130 mmol/L (reference 135-145 mmol/L) near her baseline level. During her 8 day stay she experienced significant fluctuations of serum sodium with a peak level of 151 mmol/L and a nadir of 123 mmol/L. Despite these shifts she experienced no adverse neurological symptoms. 3 weeks later she was again admitted for planned chemotherapy. During this admission she received the same medication treatment protocol as her prior stay, however, the management principles for ADI suggested by Cuesta et al. were applied. The result was a more stable serum sodium with a range of 130-145 mmol/L and no change in concentration by more than 5 mmol/L in a single 24 hour period. Patient was clinically stable and asymptomatic throughout her hospital stay Discussion: When compared to diabetes insipidus with intact thirst sensation, patients with ADI have been shown to be at increased risk for both hypernatremia and hyponatremia during inpatient admission. The risk is further increased when the admission is for an illness not related to pituitary dysfunction. This case represents an important clinical lesson in ADI where simple management principles led to a drastic change in the patient’s serum sodium. Fortunately, this patient tolerated the sodium shifts well, and did not require critical care interventions to correct her dysnatremia. Among the most important principles were transition from intranasal to oral DDAVP for a more predictable treatment response and the use of oral fluids instead of IV whenever possible. Applying these principles at the time of admission allowed for a better understanding of the treatment goals by the multidisciplinary healthcare team. Although ADI is rare, applying these simple interventions at the time of admission is likely to benefit all patients with diabetes insipidus. References: Cuesta, Martin; Hannon, Mark, Thompson, Christopher. Adipsic Diabetes Insipidus in Adult Patients.Pituitary, 2017; 20: 372-380