An Ultra-Elderly Case of Acute-Onset Autoimmune Type 1 Diabetes Mellitus

We herein described a 96-year-old woman who was referred to our hospital for a drowsy state. Since her blood glucose level was 600 mg/dL, HbA1c was 11.2%, and serum beta-ketone bodies were low, she was diagnosed with diabetic ketosis and hyperglycemic hyperosmolar state. Acute-onset type 1 diabetes mellitus was diagnosed based on the diagnostic criteria for acute-onset type 1 diabetes mellitus (2012) by the Committee of the Japan Diabetes Society. There are currently no epidemiological data available for the elderly with acute-onset type 1 diabetes in the Japanese population. This case revealed that acute type 1 diabetes may develop not only in the young-old or old-old, but also in the ultra-elderly. To the best of our knowledge, our case is the oldest among ultra-elderly cases of acute-onset type 1 diabetes mellitus.