A 41 year old man from an Indian family whose father had type 2 diabetes presented to his general practitioner with a four week history of increasing thirst and polyuria. He had not noticed any weight loss. Blood tests were arranged to confirm the diagnosis of diabetes. One week later, after having to push his car home, he began to feel exhausted and developed intermittent vomiting, which he attributed to exertion. Over the next two days he became more unwell, and the out of hours primary care service was contacted. He was reviewed urgently and admitted with diabetic ketoacidosis. A spectrum of autoimmune diabetes presents in adulthood, with type 1 diabetes characterised by the requirement of insulin at diagnosis to control glycaemia and prevent ketogenesis. Latent autoimmune diabetes of adulthood (LADA) also occurs but with much slower progression to requiring insulin after initial diagnosis. #### How common is late onset type 1 diabetes? Similar rates of ketoacidosis are seen in patients with type 1 diabetes at diagnosis in adulthood and childhood,3 and diagnostic delay is thought to account for many presentations with ketoacidosis in children.4 Although the classic symptoms produced by hyperglycaemia are unlikely to be missed, there may be a delay in accurately identifying patients requiring insulin at diagnosis if there is a clinical resemblance to type …
