Neuroleptic malignant syndrome following cardiac surgery: successful treatment with dantrolene.

Neuroleptic malignant syndrome (NMS) is a rare idiosyncratic reaction to neuroleptic drugs, which is potentially fatal. It has been occasionally reported that NMS occurs subsequently after surgery. We report a case of a 53-year-old male patient who developed NMS following cardiac surgery due to the resumption of zotepine. The patient was attacked with hyperthermia, sweating, significant shivering, trembling of the fingers, disturbed consciousness and extreme muscle rigidity after the resumption of zotepine. Furthermore, laboratory measurements revealed increased levels of serum blood urea nitrogen, creatinine and creatine phosphokinase. In addition, elevation in white blood cell counts and myoglobinemia were also observed. After a diagnosis of NMS was established, administration of zotepine was stopped and treatments with administration of dantrolene and a large amount of fluid infusion intravenously were started. Following these treatments, the clinical symptoms subsided and the laboratory findings improved without need for hemodialysis. Dantrolene, which is able to effectively impede the abnormal flow of calcium from the sarcplasmic reticulum into the muscle cytoplasm, was beneficial to reduce the clinical symptoms of NMS. We hereby present a patient with NMS following cardiac surgery, and discuss its subsequent management.