A Case of Fulminant Type 1 Diabetes in a Patient with Type 2 Diabetes Mellitus

Fulminant type 1 diabetes mellitus is a recently identified subtype of type 1 diabetes characterized by abrupt disease onset, a very short (<1 week) duration of diabetic symptoms, acidosis at diagnosis, negative status of islet-related autoantibodies, and virtually no C-peptide secretion. Cases of fulminant type 1 diabetes are prominently observed in East Asia, with several case reports and studies having originated from Japan. Indeed, a recent study from Japan reported that fulminant type 1 diabetes accounts for 15–20% of type 1 diabetes cases associated with onset of ketosis or ketoacidosis. Since 2005, several fulminant type 1 diabetes cases have also been reported in South Korea; however, there have been no reports of cases in patients previously diagnosed with type 2 diabetes mellitus. Here, we report a rare case of fulminant type 1 diabetes in a patient previously diagnosed with type 2 diabetes.