Insulin Autoimmune Syndrome: A Case Report

Insulin Autoimmune syndrome is a very rare endocrinal disease characterized by repeated hypoglycemia in the presence of elevated serum insulin and positive insulin autoantibodies, in the absence of administration of exogenous insulin, commonly patients with insulin autoimmune syndrome will be harboring other autoimmune diseases that could be active clinically or inactive and only diagnosed by positive serological markers.

In this chapter, we will discuss two clinical cases followed by discussions and my personal clinical approach in the absence of guidelines.

Due to the disease's rarity, Hirata disease is frequently misdiagnosed, which exposes patients to needless testing and surgery. Hirata disease is an insulin autoimmune disease marked by non-exogenous hyperinsulinemic postprandial hypoglycemia caused by elevated insulin autoimmune antibodies (IAS), without exogenous insulin and without pathological abnormalities of pancreatic islets cells.

The disease is uncommon in non-Asian populations, among the Caucasian population, most of the cases are due to drug exposure, autoimmune diseases or hematological malignancies, sometimes Hirata disease can be triggered by viral infection.

In this manuscript, we presented a case of autoimmune insulin hypoglycemia, the patient was subjected to a few unnecessary investigations before reaching the correct diagnosis, we reviewed the recent literature about autoimmunity of endogenous insulin hypoglycemia, we also will suggest the best practice based on our experience given that there are no guidelines to follow due to the rarity of the disease. Autoimmune insulin syndrome and insulin syndrome type B should be in the differential diagnosis of hyperinsulinemia hypoglycemia, and should be ruled out before proceeding with any expensive investigations or surgery.