MON-040 Idiopathic Arginine Vasopressin Deficiency - Rare, But Real

Abstract Disclosure: N. Bhuiya: None. F. Ziyadeh: None. P. Rao: None. Arginine vasopressin deficiency (AVP-D), formerly known as central diabetes insipidus, is a rare endocrine disorder where there is insufficient production of vasopressin, or antidiuretic hormone (ADH). However, 30-50% of AVP-D cases are more commonly idiopathic. A 72-year-old female with a history of abdominal aortic aneurysm (AAA), hypertension, congenital deafness, gallstone pancreatitis status-post cholecystectomy, depression, and hypercholesterolemia presented with altered mental status and elevated blood pressure and was admitted for hypertensive encephalopathy. Hospital course was complicated by an enlarged AAA, hypernatremia, and hypercalcemia. Patient had clinical improvement with a nicardipine drip, D5W IV fluids, desmopressin, and cinacalcet. Clinical response to desmopressin was consistent with arginine vasopressin deficiency (AVP-D). Additional work up for AVP-D was unremarkable. Copeptin levels, however, were low. Patient was arranged follow-up with outpatient pituitary clinic for idiopathic AVP-D. Patients with idiopathic AVP-D will require regular endocrinology follow-up and repeat biochemical testing as idiopathic AVP-D can be the first manifestation of an underlying evolving pathology. Presentation: Monday, July 14, 2025