RESUMO
Autoimmune hypoglycemia is characterized by hyperinsulinemia, fasting hypoglycemia, and the presence of insulin auto- antibodies without previous exposure to exogenous insulin. We experienced a case of autoimmune hypoglycemia without diabetes mellitus or any evidence of insulinoma. The insulin auto-antibody and insulin receptor auto-antibody were present. We diagnosed the patient as having autoimmune hypoglycemia and treated with glucocorticoid. After treatment, the hypoglycemic symptoms were resolved. However, four months later, the patient was readmitted with transient diabetic ketoacidosis. After recovery, he showed no signs of diabetes mellitus. We believe that insulin auto-antibodies may play a role in autoimmune hypoglycemia and diabetic ketoacidosis, but its role and mechanism are not precisely known. Further studies are needed to define the action mechanisms and the functions of insulin auto-antibodies: here we present case with a relevant literature.