S2754 Noninsulinoma Pancreatogenous Hypoglycemia Syndrome (NIPHS) and Severe Portein-Calorie Malnutrition; Unexpected Outcomes After Gastric Bypass Surgery

Abstract

INTRODUCTION: Bariatric surgery is the most effective way to achieve a clinically significant weight loss in severely obese patients but rarely it can cause Noninsulinoma pancreatogenous hypoglycemia syndrome (NIPHS) and severe protein-calorie malnutrition which happened in our case. CASE DESCRIPTION/METHODS: 49 years old female with a history of Roux-en-Y gastric bypass (2005) admitted for altered mental status secondary to hypoglycemia ( FS 25) and multiple electrolyte abnormalities ( Na 158, K 2.5, BUN 50, Cr 2.5). She was acutely managed resulting in improvement in mental status. She endorsed continued weight loss for the last 6 months along with anorexia. Upper endoscopy and Colonoscopy did not reveal any cause. Her hospital course was complicated by recurrent episodes of hypoglycemia. Further workup raised the possibility of Noninsulinoma pancreatogenous hypoglycemia syndrome(NIPHS) for which diazoxide was started. A feeding tube was placed in the remnant stomach because of continued weight loss. The patient was followed after 2 months by the bariatric surgery team and underwent reversal of RYGB with uneventful post-op recovery. DISCUSSION: Noninsulinoma pancreatogenous hypoglycemia syndrome (NIPHS) and severe protein-calorie malnutrition are extremely rare complications after bariatric surgery. NIPHS is characterized by endogenous hyperinsulinemic hypoglycemia that is not caused by an insulinoma. Histopathology specimens have revealed islet cell hypertrophy and sometimes islet cell hyperplasia. The predominant clinical feature is postprandial hypoglycemia. Biochemical findings are similar to insulinoma which include elevated plasma insulin, C-peptide, and proinsulin concentrations. Definitive diagnosis is made by EUS guided pancreatic biopsy which might be difficult to do in RYGB patients. In case reports, octreotide, verapamil, diazoxide, and acarbose have reportedly improved hypoglycemic symptoms. In severe cases, partial or subtotal pancreatectomy is performed. Severe protein-calorie malnutrition can cause continued weight loss years after bariatric surgery. It can be managed successfully with nutritional support in most of the cases. Patients may also require a psychological evaluation and/or counseling to determine the degree to which a psychosocial etiology is involved. It is important to rule out and treat all possible underlying mechanical and behavioral causes before considering a surgical revision such as the lengthening of the common channel or surgical reversal.