Increased myophosphorylase a in malignant hyperthermia

BECAUSE susceptibility is usually acquired by autosomal-dominant inheritance, 1 many relatives of patients who have had attacks of malignant hyperthermia are at risk. Elevated serum creatine kinase2 or increased sensitivity of isolated muscle to drugs, such as caffeine, that trigger muscle contraction3 may be used to discriminate susceptible from normal relatives. However, detection of this life-threatening trait remains a problem because serum creatine kinase may be normal in survivors of attacks, 4 and studies of muscle physiology are performed in only a few specialized laboratories. Muscle of persons susceptible to malignant hyperthermia is more sensitive to caffeine because of abnormal function of. © 1980, Massachusetts Medical Society. All rights reserved.