Endocrine Abstracts

Insulinomas, uncommon neuroendocrine tumours, may produce insulin-induced hypoglycemia. It causes neuroglycopenia and autonomic sympathetic dysfunction. Glucose immediately relieves these sensations. Hypoglycemia without plasma sulfonylurea and increased C-peptide is diagnostic. The tumour must be found before surgery.

Introduction: Hypoglycemia is caused by insulinomas. Insulinoma, the most frequent functional pancreatic tumour, occurs just four times per million. Extra-pancreatic insulinomas are rare. This unusual tumour causes sympathetic and neuroglycopenic symptoms.

Case Presentation: 24-year-old boy who presented to endocrine department with recurrent episodes of hypoglycemia. This case was challenging because of the patient’s history of anorexia nervosa and substance abuse. He used substances, including marijuana, cocaine, and MDMA, in the past. He had a history of at least six years of recurrent admissions to emergency care with a diminished level of awareness and seizure activity and blood glucose levels below 2.2. His symptoms recovered once his hypoglycemia was treated. Multiple studies were done to determine his symptoms because he was not diabetic. He was tested for liver, kidney, and hormonal dysfunction, such as adrenal insufficiency. In the limited supervised fast demonstrated, glucose was 1.8 mmol/l, insulin 52 pmol/l, C-peptide 795 pmol/l, beta-hydroxybutyrate less than 100 umol/l, and the IGF2:IGF-1 ratio was 2.4. Insulin antibody-negative. Negative sulfonylureas. Radiological screening proceeded. unremarkable pancreas MRI. No pancreatic lesion, especially an arterial-enhancing lesion identified. Gallium-deficient PET/CT showed no insulinoma. Endoscopic ultrasonography and biopsy were inconclusive for endogenous insulinoma.

Management: Continuous glucose monitoring equipment was supplied to check his hypoglycemia. It was difficult to control his hypoglycemia without medicine, so he began taking 150 mg of diazoxide three times a day to avoid further episodes. Further investigations are continuing. A supervised 72-hour fast was performed, which reciprocated the result of the limited fast. We chose selective calcium stimulation to locate the insulinoma. He was advised to cease diazoxide seven days before the test to prevent interference. A catheter was implanted in the right hepatic vein, proximal gastroduodenal, proximal splenic hepatic, and superior mesenteric regions. Post-calcium gluconate insulin and C-peptide levels were elevated, although we could not discern a gradient in any arterial territory to validate localization.

Recommendation: 1. Consider continuing medical management, control your diet, and continue to follow up.

2. Consider an exploratory laparotomy to see if any lesion can be identified.

3. Consider partial pancreatectomy, which might be able to help with the frequency of hypoglycemia but might be tricky for iatrogenic diabetes and surgical complications.