Insulin autoimmune syndrome: A report of two cases

Abstract

Insulin autoimmune syndrome (IAS) also known as Hirata's disease is a rare endocrine disease. It is a form of autoimmune endogenous hyperinsulinemic hypoglycemia, which develops when genetically predisposed individuals get exposed to triggering factors such as viral infection or certain medications containing sulfhydryl groups. It is important to consider IAS in the differential diagnosis of hypoglycemia as its incidence seems to be increasing worldwide. In this article, we summarize a report of two cases of IAS and their clinical manifestations, biochemical characteristics, their step-by-step diagnosis, and also prompt utilization of continuous glucose monitoring system as a monitoring tool for appropriate management. The first patient who presented with hypoglycemic episodes had recently suffered from a viral pneumonia, which probably acted as a superantigen and triggered development of IAS. The second patient also had hypoglycemic episodes, which were used to recover after intake of glucose-containing liquids. Alpha-lipoic acid containing multivitamin may have triggered the development of IAS in the second patient. The tests performed showed high serum insulin and C-peptide levels along with insulin autoantibody positivity confirming the diagnosis of Hirata's disease. Immunosuppression therapy was not required as both the patients responded well to diet modification and corticosteroid therapy. It is important to be mindful while prescribing alpha-lipoic acid-containing supplements though it has good antioxidant properties as it is presumed to be associated with increasing number of IAS cases.