12417 Atypical Patterns Of Hypoglycemia Post-bariatric Surgery Due To Pancreatic Insulinoma

Abstract Disclosure: K.A. Chopra: None. Accurately diagnosing an insulinoma in patients who have had bariatric surgery can be challenging because the autonomic symptoms of palpitations, tremors, anxiety and neuroglycopenic hypoglycemia symptoms of confusion and loss of consciousness may overlap with dumping syndrome or be attributed to non-insulinoma pancreatogenous hypoglycemia. When evaluating hypoglycemia, it is crucial to obtain a detailed history of the pattern and timing of hypoglycemia episodes and collect a critical sample of insulin, proinsulin, c-peptide levels during an episode of low glucose to prevent misdiagnosis. 58-year-old woman with hypertension, obesity, and history of laparoscopic sleeve gastrectomy presented for evaluation of hypoglycemia. The patient lost 100 pounds after her sleeve gastrectomy. Within the past year, the patient had two hospitalizations for severe symptomatic hypoglycemia with associated loss of consciousness. Imaging showed atrophic pancreas and she was discharged with a prescription for daily prednisone without critical sample testing for insulin or c-peptide levels. She sought a second opinion for her hypoglycemia at UCM. Since she was taking prednisone for 10 months prior to initial evaluation at UCM, evaluation for adrenal insufficiency could not be completed initially. She started continuous glucose monitoring which showed multiple daily episodes of hypoglycemia, fasting and at other various timepoints. Fasting labs showed low glucose of 20 mg/dL (RR 60-99 mg/dL), elevated proinsulin 120 pmol/L (RR 3.6- 22 pmol/L), inappropriately normal insulin 16.4 uIU/mL (RR <28.5 uIU/mL), and inappropriately normal c-peptide 0.82 pmol/mL (RR 0.30-2.35 pmol/mL), consistent with insulinoma. CT abdomen showed 1.4 cm arterially enhancing round lesion in the pancreatic body. Endoscopic ultrasound showed 13 mm mass in the pancreatic body with fine needle aspiration with pathology showing a well-differentiated neuroendocrine tumor. She received stress dose hydrocortisone preceding surgery and underwent successful enucleation of 1.6 cm pancreatic neuroendocrine tumor. A few weeks after her surgery, her HPA axis was re-evaluated, and steroids were discontinued. She has had no episodes of hypoglycemia since. Although hypoglycemia can be associated post-bariatric surgery, most patients develop postprandial hypoglycemia due to surgical alterations in alimentary flow leading to increased incretin and insulin secretion (Mulla et al 2016). Therefore, it is important to consider insulinoma in the differential diagnosis of post-bariatric surgery patients presenting without typical postprandial patterns of hypoglycemia. Reference: Mulla CM, Storino A, Yee EU, Lautz D, Sawnhey MS, Moser AJ, Patti ME, Insulinoma After Bariatric Surgery: Diagnostic Dilemma and Therapeutic Approaches. Obes Surg. 2016 Apr;26(4):874-81. Presentation: 6/1/2024