Endocrine Abstracts

JOINT2511

Introduction: Insulin autoimmune syndrome (IAS) is a rare cause of hypoglycemia characterized by elevated serum insulin levels and autoantibodies against endogenous insulin that cause spontaneous hypoglycemic episodes. The aim of this case is to emphasize the significance of evaluating IAS in individuals with recurrent hypoglycemia.

Case: A 64-year-old man who had hypoglycemia episodes for 2 months was referred to our endocrine clinic with a suspicion of insulinoma. The patient has no known disease other than choledocholithiasis. In blood tests performed due to hypoglycemia, fasting serum glucose (FSG) was 42 mg/dL, insulin level was 1523.5 mU/l, c-peptide was 6.11 µg/l, and HbA1c was 6.3%. We conducted a 72-hour fasting test to confirm the diagnosis of endogenous hyperinsulinemia. After 14 hours, hypoglycemic symptoms emerged, and FSG was 40 mg/dL, insulin was 212.9 mU/l, and C-peptide was 4.9 µg/l. There was no blood glucose response after glucagon administration. MRI of the abdomen, Gallium-68 Dotatate scintigraphy, and endoscopic ultrasonography (EUS) failed to detect the tumor. The anti-insulin antibody was 91.5% (<8.2). Autoimmune hypoglycemia was considered in the patient. We reviewed the patient’s recent prescriptions to determine the triggering factor, as he had been describing hypoglycemia for the last few months. We saw prescriptions for dexketoprofen, paracetamol, and erdosteine. We adjusted the patient’s diet regimen and performed close blood sugar monitoring. All of the patient’s medications were discontinued, and agents that could trigger hypoglycemia were avoided. During follow-up, the patient’s episode frequency decreased, and hypoglycemia was not at a level that would affect his daily life.

Conclusion: Insulin autoimmune syndrome is a rare syndrome that causes episodes of hypoglycemia. This case highlights the importance of considering IAS as a differential diagnosis in patients presenting with recurrent hypoglycemia secondary to hyperinsulinemia. The standard diagnostic test for IAS is the measurement of insulin autoantibodies. Clinicians should keep in mind patients with atypical hypoglycemia, which enables timely diagnosis and eliminates the necessity for expensive imaging methods or invasive surgical interventions. The primary treatment for IAS is a diet consisting of low glycemic index foods. Additionally, steroids may be utilized as an adjunctive therapy.