A Therapeutic Paradox: Using Insulin to Treat Gastric Bypass Associated Hyperinsulinemic Hypoglycemia

Hyperinsulinemic hypoglycemia is an uncommon complication of gastric bypass surgery. Diagnosis of this condition and optimal treatment remains a challenge. We present a case of gastric bypass-associated hyperinsulinemic hypoglycemia successfully treated with insulin.

Case Description:

A 40-year-old female with a medical history of undifferentiated connective tissue disease, schizoaffective disorder, fibromyalgia, Raynaud's phenomenon, pulmonary embolism, and morbid obesity status post gastric sleeve and a revision to Roux-en-Y gastric bypass was evaluated for recurrent postprandial hypoglycemia occurring about 1-2 hours post meals. The symptoms developed one year after gastric bypass. She initially had neuroglycopenic symptoms but now had hypoglycemia unawareness with several hypoglycemic emergencies requiring Emergency Medical Service intervention that necessitated her getting a Continuous Glucose Monitor. The lowest sugar on record was 27mg/dl on self-monitoring blood glucose. Initial symptoms of hypoglycemia and hypoglycemia would resolve upon administration of glucose. There was no fasting or nocturnal hypoglycemia and eating lower carbohydrate meals helped. She was offered a biochemical evaluation for hypoglycemia but was unwilling to do a fasting or mealtime study. Abdominal imaging did not reveal pancreatic masses. Based on the clinical presentation, a diagnosis of post gastric bypass hyperinsulinemic hypoglycemia was suspected.

She received nutritional counseling on eating low, complex carb, and frequent meals. Multiple medications were tried without success that included Acarbose, Octreotide, Diazoxide, and Metformin. The patient was then started on Aspart insulin 1 unit per 25 grams of carbohydrates before meals with the goal of decreasing the postprandial glycemic spike that would ultimately lead to hypoglycemia. This caused a marked reduction of postprandial hypoglycemic events and no further hypoglycemic emergencies were reported.

Discussion:

We present a novel non-invasive and cost-effective option for treating hyperinsulinemic hypoglycemia after gastric bypass surgery. The use of insulin therapy before meals targeted to avoid a postprandial spike reduced the incidence of postprandial hypoglycemia by reducing the stimulus on endogenous pancreatic insulin release.