Type B insulin resistance syndrome with fasting hypoglycemia and postprandial hyperglycemia

Type B insulin resistance syndrome is a rare disease that manifests as severe insulin resistance and hyperglycemia. Few cases with hypoglycemia are reported. We describe a patient with type B insulin resistance syndrome with the presence of insulin receptor antibodies that showed severe hypoglycemia and hyperglycemia and review the clinical features. The patient was a 65-year-old Japanese male diagnosed with type 2 diabetes in June 2012. In August, he was admitted to an emergency room after suffering a hypoglycemic coma several times and then referred to our medical center. His HbA1c was 7.9 %, fasting plasma glucose was 46 mg/dl, and serum insulin level was 310 µU/ml; however, the postprandial glucose level was high (200–400 mg/dl). Plasma glucose decreased slightly after an intravenous 0.1 U/kg insulin challenge test. The findings suggested severe insulin resistance. As anti-insulin receptor antibody was detected (93.3 %, radio-receptor assay), we diagnosed type B insulin resistance syndrome. The patient was administered prednisolone, and the symptoms disappeared. This report details a case of type B insulin resistance syndrome with both hypoglycemia and hyperglycemia, which was successfully treated with only prednisolone.