A Rare Case of Adult Nesidioblastosis Causing Persistent Hypoglycemia in Patient With Atrial Fibrillation and Chronic Kidney Disease

Abstract

Abstract Nesidioblastosis is a very rare adult disorder in the absence of gastrointestinal surgery. Nesidioblastosis is a disorder of the endocrine pancreas causing hyperinsulinemic hypoglycemia. We describe a case of 83 year-old Caucasian male, with a 3-year history of severe refractory hypoglycemia with glucose level below 2.1 mmol/L. Confusion and sleepiness were reported as his neuroglycopenic symptoms. According to his family, his symptoms improved within 30 minutes of drinking orange juice. Hypoglycemia episodes mostly occurred while fasting and post exercise (after playing golf). His work up included low venous plasma glucose levels, high insulin and C-peptide levels that were consistent with an insulinoma. His history is remarkable for chronic kidney disease stage 3, penicillin allergy and atrial fibrillation with loop recorder for cardiac rhythm monitoring, which precluded him from undergoing CT with IV contrast or MRI studies. Abdominal computed tomography with oral contrast did not reveal any lesion. In an attempt to localize the suspected Insulinoma, he had celiac angiogram and portal vein sampling, which were inconclusive. He had a PET scan with dotatate that showed increased amount activity in the uncinate process of the pancreas. He was diagnosed with insulinoma and placed on monthly lanreotide injections, however continued to have severe hypoglycemia episodes. Due to persistent refractory hypoglycemia, patient underwent distal pancreatectomy and splenectomy and the histological findings were consistent with nesidioblastosis. Patient developed hyperglycemia in the post-operative course which was controlled with a carb consistent diet. This case demonstrates that differentiation between insulinoma and nesidioblastosis is very challenging, and in most cases, the diagnosis is made post operatively based on histologic findings.