Neuroleptic malignant syndrome presenting as hyperosmolar non-ketotic diabetic coma

A 50-year-old man presented with hyperosmolar non-ketotic diabetic coma associated with the neuroleptic malignant syndrome (NMS) after intramuscular treatment with haloperidol. It is suggested that NMS may occur as a complication of uncontrolled diabetes mellitus with dehydration. Conversely, NMS might precipitate diabetic coma in patients with previously well controlled blood glucose.