Endocrine Abstracts

Introduction: Post-bariatric hypoglycemia or late dumping syndrome is a complication of bariatric surgery occurring 1- 3 years post operatively and 1-3 hours post meal. Presentation includes hypoglycemia, lethargy, dizziness and diaphoresis. When hypoglycemia occurs prior to this time frame, other etiologies should be considered. This abstract reviews the presentation of hypoglycemia in the early post-operative stage of laparoscopic sleeve gastrectomy.

Background: A 48-year-old female presented with recurrent hypoglycaemic episodes 11 days following laparoscopic sleeve gastrectomy. Her symptoms included dizziness, confusion, diaphoresis and fatigue. Self-monitoring blood glucose readings confirmed hypoglycaemia. Hypoglycaemia was documented within 24 hours of initiating a 72-hour fast. Laboratory evaluation revealed elevated insulin (216 pmol/l) and C-peptide (1343 pmol/l) levels, with a negative sulfonylurea screen, suggesting endogenous hyperinsulinism. CT and MRI of the pancreas were unremarkable. Endoscopic ultrasound identified an 11–12 mm lesion in the pancreatic head. Fine needle aspiration confirmed insulinoma. Diazoxide therapy was initiated but was subsequently discontinued due to deranged liver enzymes. Whipple’s procedure was deferred due to inadequate postoperative weight loss. Tirzepatide was commenced to optimise weight management and with 23 kg loss she currently eligible for surgery.

Discussion: This case underscores the importance of considering insulinoma in patients with early-onset hypoglycaemia following bariatric surgery. In the preoperative period a low-calorie liver shrinking diet improves the mobility of the liver intraoperatively, causing rapid visceral fat reduction, improving insulin sensitivity and likely unmasked the insulinoma. Tirzepatide proved effective promoting weight loss with euglycemia in the setting of hyperinsulinemia. Though there is documented use of incretin mimetic agents in reactive hypoglycaemia and late dumping syndrome, use in the setting of hyperinsulinemia has not been documented. To our knowledge this has been the first successful case. Tirzepatide may be an effective preoperative therapy to facilitate surgical candidacy in patients with morbid obesity and hyperinsulinism.