A Case of Insulin Autoimmune Syndrome in an Indian Male Taking Alpha-Lipoic Acid

Insulin autoimmune syndrome [IAS, Hirata disease (HD)] is a rare cause of recurrent spontaneous hypoglycemic episodes, characterized by high serum insulin levels and high titers of autoantibodies against endogenous insulin. We report a case of a previously healthy Indian male presenting with recurrent episodes of hypoglycemia with no prior exposure to exogenous insulin. Regular glucose monitoring was done. Laboratory tests showed insulin > 1000 mu IU/mL and C-peptide levels of 12.8 ng/ml. The patient had high titers of insulin autoantibodies (IAA) (> 100 units/mL; normal range: < 10 units/mL), which indicated a diagnosis of IAS. The patient was consuming alpha-lipoic acid; sulfhydryl-containing compounds have been linked to IAS. This case report highlights the importance of IAA titers in first-line investigations for hypoglycemia in a non-diabetic patient with strikingly high blood insulin levels and discusses the potential relationship between IAS and alpha-lipoic acid.