Hyperglycemia as a symptom of neuroleptic malignant syndrome

A 67-year-old schizophrenic woman developed neuroleptic malignant syndrome (NMS). She had mild diabetes mellitus, which had been controlled with diet therapy only. Upon the onset of NMS, hyperglycemia of up to 490 mg/dl developed. The hyperglycemia persisted during the NMS episode despite insulin treatment, and subsided only after the symptoms of NMS disappeared. The present report suggests that hyperglycemia may develop as a symptom of NMS, especially in patients with pre-existing impaired glucose tolerance, and that blood glucose should be monitored during NMS episodes.