[Underlying causes of diabetes mellitus].

In patients with hyperglycaemia plus obesity and cardiovascular disease, the diagnosis of type 2 diabetes mellitus is likely to be made and this is usually followed by the start of antihyperglycaemic therapy. This pragmatic approach, however, does not always turn out to be the correct one. We describe two patients with occult conditions that had caused or aggravated diabetes mellitus (DM): a 46-year-old man with acromegaly and a 41-year-old woman with Cushing's disease. After neurosurgeries were performed, the requirement for antihyperglycaemic treatment markedly decreased (case 2) or even disappeared (case 1). Physicians treating patients with DM should ask themselves what the cause of the disease could be; the recognition and treatment of that underlying condition may substantially decrease the amount of insulin required and may even cause the disappearance of DM altogether.