A type 2 diabetic patient with liver dysfunction due to human insulin.

A 45-year-old man had been complaining of thirst and polydypsia for the last 3 months and was diagnosed as having type 2 diabetes mellitus because his fasting blood glucose showed 221 mg/dl with positive urinary ketone. He was hospitalized to a private hospital and Penfil 30R was started. However, serum gamma-GTP and aminotransferases began to elevate after insulin treatment and exceeded 1000 IU/l. Insulin was discontinued and serum gamma-GTP and aminotransferases returned close to the normal range. Since his glycemic control became poor again, Penfil 30R was restarted and serum gamma-GTP and aminotransferases elevated again. Therefore, insulin was discontinued and the patient was referred to the Third Department of Internal Medicine, Yamanashi Medical University Hospital because of liver dysfunction. His plasma glucose decreased by diet therapy, and improved further by the administration of glibenclamide. After obtaining informed consent, Humalin R was challenged. Seven days after insulin injection, serum aminotransferases began to elevate again. Lymphocyte stimulation test was negative against three preparations (Penfil R, Penfil N and Humalin R). The present case suggests that human insulin itself can cause liver dysfunction and we need to pay more attention to liver function tests when we start insulin treatment.