A patient with type 1 diabetes mellitus who developed exogenous insulin antibody syndrome ameliorated by immunosuppressive treatment for concomitant systemic lupus erythematosus: A case report

Abstract

We present a case of a male patient with type 1 diabetes mellitus who developed exogenous insulin antibody syndrome （EIAS）, ameliorated by immunosuppressive treatment including glucocorticoid for concomitant systemic lupus erythematosus （SLE）. A 43-year-old man with fulminant type 1 diabetes mellitus developed severe insulin resistance after approximately 8months of insulin therapy. He required 〜270insulin units/day, and EIAS was diagnosed based on the clinical course and the extremely high-binding rate of the insulin antibody. Two years later, he developed proteinuria, lymphopenia, low complement levels, and positive autoantibodies, and SLE was diagnosed. Glucocorticoid pulse therapy was started, followed by administration of mycophenolate mofetil and hydroxychloroquine. Although hyperglycemia might have been associated with glucocorticoid pulse therapy, the required insulin dose was reduced to 18 units/day. In diabetic patients who develop EIAS, the coexistence of immunological disorders such as SLE should be monitored, and glucocorticoid pulse therapy may be an effective alternative treatment option for EIAS.