[Lack of sensitivity to per-anesthetic malignant hyperthermia in 32 patients who developed neuroleptic malignant syndrome]

The aim of this study was to verify whether a relationship exists between neuroleptic malignant syndrome (NMS) and anaesthetic-induced malignant hyperthermia (MH) or not. The in vitro halothane-caffeine tests were performed on muscle tissue obtained from 32 patients with documented NMS episodes. The diagnosis of NMS relied on Levenson's criteria. The results, expressed in accordance with the criteria of the European MH Group, defined 29 subjects as MH non-susceptible. Three patients were classified as MH equivocal. These findings demonstrate the lack of any link between NMS and MH. Therefore, patients with a history of NMS are not likely to be at risk of developing MH and special measures against MH are not required for anaesthesia in these patients.