Criteria
American Malignant Hyperthermia Group criteria based on the positive caffeine halothane contracture test[84]
MH-susceptible muscle produces diagnostic contractures in the presence of either halothane or caffeine. All patients with a diagnostic contracture are considered at risk for a life-threatening episode during exposure to inhalation anesthetics or succinylcholine.
Only patients whose muscle did not produce a diagnostic contracture on exposure to either halothane or caffeine are considered MH normal. These patients are able to receive inhalation anesthetics with no increased risk.
European Malignant Hyperthermia Group criteria based on the in vitro contracture test[75]
MH-susceptible muscle produces diagnostic contractures in the presence of caffeine and halothane, or either agent alone.
MH positive response to halothane (MHSh): muscle produces diagnostic contractures only in the presence of halothane. MH positive response to caffeine (MHSc): muscle produces diagnostic contractures only in the presence of caffeine. Individuals whose muscles produce any of these responses are clinically treated as being at risk of a life-threatening episode during exposure to inhalation anesthetics or succinylcholine.[56]
Only patients whose muscle did not produce a diagnostic contracture on exposure to either halothane or caffeine are considered MH normal. These patients are able to receive inhalation anesthetics with no increased risk.
European Malignant Hyperthermia Group criteria for identification of RYR1 mutations
The standards for proving that a RYR1 or other genetic variant is an MH causative mutation are rigorous. The European Malignant Hyperthermia Group provides a list of MH mutations and requirements for proving that a variant should be considered a mutation diagnostic of MH susceptibility. The European Malignant Hyperthermia Group Opens in new window Genetic counseling is indicated if a RYR1 mutation is identified that is of unknown significance.[56]
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