Background: Adult nesidioblastosis is characterised by endogenous hyperinsulinemia typically causing post-prandial hypoglycaemia, and most commonly occurs following bariatric surgery. We report a unique case of nesidioblastosis in a 67 year old female.
Case Presentation: A 5 year history of symptomatic hypoglycaemia occurred in a patient with short bowel syndrome and with a history of type 2 diabetes mellitus. In 2012 she was diagnosed with type 2 diabetes and was managed with a glucagon-like peptide (GLP) 1 agonist (Exenatide 10mcg twice a day) for 18 months. Since 2013 she had episodes of symptomatic hypoglycaemic, which were particularly worst in the last 12 months causing neuroglycopenic symptoms. Continuous glucose monitor captured 42 hypoglycaemia episodes in a two week period, with her lowest blood sugar level of 2.0 mmo/L. There was no suggestion of a medical illness or medication contributing to her hypoglycaemia, with a negative sulphonylurea screen and insulin antibody of 0.4 units (<0.7 units). There however was the suspicion of a hyperinsulinemia state following a venous fasting sample where her glucose was 8.1 mmol/L, insulin 210 mU/L (<25 mU/L) and C-peptide 3.8 nmol/L (0.2 – 1.2 mmol/L). Localizing studies did not identify a focal pancreatic lesion, and included magnetic resonance imaging, PDOPA positron emission tomography and endoscopic ultrasound. She was managed with an open distal pancreatectomy, and her operative specimen has confirmed the diagnosis of nesidioblastosis. Post-operatively she had ongoing issues with hypoglycaemia, which necessitated the use of octreotide to maintain euglycaemia.
Conclusion: We present the first case of nesidioblastosis occurring in a patient with short gut syndrome and pre-existing type 2 diabetes, managed in the past with a GLP-1 agonist, all of which may have been a predisposing factor for islet cell hyperplasia.