Autoimmune Hypoglycemia With Anti-Insulin Autoantibodies in an Eighty-One-Year-Old Woman Without Apparent Risk Factors

BACKGROUND/OBJECTIVE: Insulin autoimmune syndrome (IAS) is a very rare cause of hypoglycemia presenting with recurrent fasting or postprandial hypoglycemia episodes with elevated serum insulin levels and insulin autoantibodies. The objective of this case is to highlight the importance of considering IAS in patients with hypoglycemia. CASE REPORT: We present a case of an 81-year-old female who presented with symptoms of hypoglycemia. She was found to have hyperinsulinemic hypoglycemic episodes without any apparent risk factors for IAS. She had positive–insulin autoantibodies in her serum leading to the diagnosis of IAS. Acutely, hypoglycemia was managed with D50 pushes, oral glucose, and glucagon injection. DISCUSSION: Patients who present with hypoglycemia due to endogenous hyperinsulinemia should have IAS considered as a possible differential diagnosis. Insulin autoantibodies are measured as the gold standard diagnostic test for IAS. Foods with a low glycemic index are the primary treatment for IAS. CONCLUSION: This case presentation highlights the importance of considering IAS as a differential diagnosis in patients presenting with hypoglycemia secondary to hyperinsulinemia, even in the absence of apparent risk factors.