Abstract 104: Varied presentations of endogenous hyperinsulinemia to a tertiary care hospital- A Case Series

Background: Endogenous hyperinsulinemichypoglycemia occurs due to unregulated release of insulin causing hypoglycemia. It can occur due to islet cell tumors or diffuse enlargement of islet cells in apparently healthy adults without any prior history of gastrointestinal surgery. We describe four cases of endogenous hyperinsulinemia that presented to us with varied clinical presentations and discuss the challenges in diagnosis and management. Case Presentation Case 1: A38-year-old femalepresented with frequent episodes of loss of consciousness. She was found to have hypoglycemiawith documented endogenous hyperinsulinemia. All anatomic and functional imaging including contrast-enhanced computed tomography (CECT), endoscopic ultrasound (EUS), and Ga-68 DOTANOC positron emission tomography (DOTA -PET) were negative. An insulinomawas identified by intraoperative palpation and her symptoms resolved post-resection. Case 2: A 51-year-old female with prior diabetes mellitus was admitted with frequent hypoglycemia even after stopping anti-diabetic medications. After documenting hyperinsulinemia, a suspicious lesion was identified in the pancreatic tail on CECTthat was resected leading to resolution of hersymptoms. Case 3: A 32-year-female presented with frequent hypoglycemiaforthe past 4 years. After admission, endogenous hyperinsulinemia was documented but CECT and EUS were normal. A functional GLP-1 scan showed diffuse uptake in the whole of the pancreas suggestive of nesidioblastosis. During surgery, an intra-op frozen section confirmed diffuse islet hyperplasia and she underwent a distal pancreatectomy. She had recurrence of hypoglycemia after 3 months and is on medical therapy currently. Case 4: A 27-year female in her first trimester of pregnancy presented with hypoglycemia in whom endogenous hyperinsulinemia was documented. Magnetic resonance imaging without contrast and EUS showeda suspicious lesion in the pancreatic head with liver metastasessuggesting malignant insulinoma. She was initiated on diazoxide and octreotide and was planned for debulking surgery in the second trimester in case of persistent hypoglycemia. However, due to financial constraints, she stopped medical therapy and unfortunately expired after a month. Conclusion: These cases highlight the varied clinical presentations and diagnostic challenges encountered in a seemingly healthyindividual with hypoglycemia. Insulinoma is the underlying cause in majority; but because of small size and location, these are commonly missed on anatomical scans. Functional imaging (DOTA-PET /GLP-1 PET-CT) is emerging with better diagnostic accuracy. Diagnosis during pregnancy can pose further management challenges. [INLINE:1]