Malignant hyperthermia: a possible new variant.

A young healthy male, who had three consecutive episodes of postoperative hyperthermia was anaesthetized with special precautions to prevent malignant hyperthermia. Despite neuroleptic anaesthesia and dantrolene pretreatment, the patient experienced post-anaesthetic hyperthermia. The patient's clinical picture was almost identical to the symptoms experienced by two of his maternal relatives. All three experienced nausea, vomiting, muscle cramps and high fever which occurred between five to seven hours after general anaesthesia. The serum potassium (K) and creatinine phosphokinase (CPK) levels determined during the hyperthermic episode and on the next day were not elevated. On the basis of the patient's family history, his clinical picture, and his laboratory data, we speculate that this patient might have a form of malignant hyperthermia or a possible new variant.