An Unusual Cause of Hypoglycemia: Insulin Autoimmune Syndrome

Abstract

Insulin autoimmune syndrome (IAS) is a rare cause of hyperinsulinemic hypoglycemia characterized by antibodies to endogenous insulin without exposure to exogenous insulin. In this report, we presented a case of insulin autoimmune syndrome with a history of fasting hypoglycemia. After work up and exclusion of other causes such as insulinoma, hyperinsulinemic hypoglycemic state of the patient was considered to have been induced by etofenamate. Although IAS is generally self-limiting and dietary management and withdrawal of trigger drug are enough to maintain euglycemia, in some cases corticosteroids, plasmapheresis, rituximab can be used for treatment. In our case, despite dietary management, hypoglycemia was severe and the patient's life quality was adversely affected. After treatment with prednisolone, hypoglycemic episodes became less and less frequent. IAS should be considered as a differential diagnosis of hyperinsulinemic hypoglycemic states to avoid unnecessary interventions.