Case report: autoimmune insulin syndrome in a Chinese female with Graves' disease

We report a case of autoimmune insulin syndrome in a 27-year-old Chinese female with Graves' disease. She presented with recurrent and severe spontaneous hypoglycaemia after being treated with carbimazole. The extremely elevated serum insulin concentrations and the presence of insulin autoantibodies in this patient are important diagnostic markers of this condition. She responded well to medical treatment for hypoglycaemia with high caloric feeding and oral diazoxide with complete remission of hypoglycaemic episodes. Her thyrotoxicosis responded to carbimazole treatment given for two years but a relapse occurred six months after stopping the antithyroid drug. There was no recurrences of hypoglycaemia during the relapse of her thyrotoxicosis. This is a first case report of autoimmune insulin syndrome in a Chinese female in Southeast Asia presenting with hypoglycaemia and highlights the importance of recognising this condition as an interesting albeit rare cause for a common metabolic problem.