[Two cases of fulminant type 1 diabetes mellitus]

We report 2 elderly patients with fulminant type 1 diabetes mellitus. Case 1: A 61-year-old-man was admitted because of hyperglycemia (blood glucose level, 1,071 mg/dl) and metabolic acidosis. His hemoglobin A1c level was almost normal (5.8%), glutamic acid decarboxylase (GAD) antibody was not detected, and a low level of C-peptide (CPR) was excreted in his urine. We diagnosed his condition as diabetic ketoacidosis, and administered intensive insulin therapy. Case 2: A 77-year-old-man was admitted because of hyperglycemia (blood glucose level, 925 mg/dl). His hemoglobin A1c level was slightly high (5.9%), GAD antibody was not detected, and low levels of CPR were excreted in his urine. He showed no signs of metabolic acidosis, but showed metabolic ketosis. The findings of these cases were consistent with those of fulminant type 1 diabetes mellitus. Thus, it is necessary to consider the possibility of this disease in elderly people.