Nesidioblastosis: an uncommon complication seen post Roux-en-Y gastric bypass

Adult-onset nesidioblastosis is a rare complication of Roux-en-Y gastric bypass surgery and may occur months to years after the initial surgical procedure. It is manifested by a hyperinsulinemic, hypoglycemic state. The annual incidence of adult-onset hyperinsulinemic hypoglycemia is believed to be less than 0.1 in 1 000 000 with a mean age of onset of 47 years (1). Here, we describe a patient who presented with worsening hypoglycemic symptoms for 1 year prior to presentation that eventually progressed to hypoglycemic seizures. The onset of this hypoglycemia was 5 years after Roux-en-Y gastric bypass surgery. A full neurological evaluation, which included an EEG, head CT, and MRI, was performed to rule out epilepsy and other seizure-related disorders. After hypoglycemia was confirmed, extensive laboratory studies were obtained to elucidate the cause of the hypoglycemia and differentiate nesidioblastosis from insulinoma. Once the diagnosis of nesidioblastosis was established, a sub-total pancreatectomy was performed, and the patient was discharged and placed on acarbose, a competitive reversible inhibitor of pancreatic alpha-amylase and intestinal brush border alpha-glucosidases which slows carbohydrate absorption. The lack of information and understanding of nesidioblastosis due to its rarity makes any knowledge of this rare but important surgical complication essential. As incidence of obesity increases, the number of gastric bypasses being performed increases with it, and understanding this disease process will be essential for the primary care provider. This is the primary reason for the writing of this publication.