The risk of malignant hyperthermia in children undergoing muscle biopsy for suspected neuromuscular disorder

BACKGROUND: It is assumed that those children with known or suspected neuromuscular disorders (NMD) are at increased risk for malignant hyperthermia (MH). Despite the lack of conclusive data, most of these children are managed with a nontriggering anesthetic. This study examined the risk of MH in children exposed to a triggering anesthetic while undergoing muscle biopsy for suspected NMD. METHODS: Between 1992 and 2005, the medical records of 351 children under 21 years of age were identified as having undergone muscle biopsy for suspected NMD. Of these, only 274 received a volatile anesthetic agent or succinylcholine and were included for study. Records were examined for evidence of MH or rhabdomyolysis. RESULTS: No patient exhibited signs or symptoms suggestive of MH. One patient was found, by muscle biopsy, to have evidence of rhabdomyolysis prior to exposure to a volatile anesthetic. Of 274 patients, only three received succinylcholine. None developed MH or rhabdomyolysis. The estimated risk of a patient with suspected NMD developing MH as a result of exposure to volatile anesthetic agents during muscle biopsy is 1.09% or less. CONCLUSION: The estimated risk of MH or rhabdomyolysis is 1.09% or less in a diverse population of children with suspected NMD.