Refractory Hyperinsulinemic Hypoglycemia as a Complication of Roux-en-Y Gastric Bypass Surgery

This case involves a 45-year-old woman with severe obesity who underwent Roux-en-Y gastric bypass (RYGB) surgery. After one year, she developed daily episodes of severe hypoglycemia, presenting with symptoms of palpitations, diaphoresis, and syncope. The patient was diagnosed with endogenous hyperinsulinemic hypoglycemia, a condition characterized by abnormally high insulin levels leading to low blood glucose, commonly associated with insulinoma. In rare instances, this can be due to nesidioblastosis, an overgrowth of pancreatic beta cells, which is more prevalent in individuals who have undergone bariatric surgery. Diagnostic evaluations included blood tests, abdominal computed tomography and magnetic resonance imaging, continuous glucose monitoring, and hepatic venous sampling to exclude insulinoma. This report details the diagnosis and unsuccessful treatment of endogenous hyperinsulinemic hypoglycemia following RYGB surgery. Interventions included dietary modifications (small, frequent, low-carbohydrate meals), medical management with acarbose 100 mg three times daily, diazoxide 150 mg three times daily, verapamil 40 mg twice daily, and surgical reversal of the RYGB. Ultimately, a percutaneous gastrostomy tube was placed for 24-hour continuous parenteral feeding. Despite these extensive treatment efforts, the patient continues to experience frequent hypoglycemic episodes four years after the bariatric procedure.