Contempo Updates Section Editor: Sarah Ringold,
MD, Fishbein Fellow.
Author Affiliations: Department of Anesthesiology
& Critical Care Medicine, The Children’s Hospital of Philadelphia,
University of Pennsylvania School of Medicine, Philadelphia (Dr Litman); Department
of Medical Education, Saint Barnabas Medical Center, Livingston, New Jersey
and Mount Sinai School of Medicine, New York, NY (Dr Rosenberg).
Quiz Ref IDMalignant hyperthermia (MH) is a pharmacogenetic clinical
syndrome that manifests as a hypermetabolic crisis when a susceptible individual
is exposed to an anesthetic triggering agent. Clinical signs include unexplained
elevation of end-tidal carbon dioxide, muscle rigidity, acidosis, tachycardia,
tachypnea, hyperthermia, and evidence of rhabdomyolysis. This process is a
result of an abnormally increased release of calcium from the sarcoplasmic
reticulum, which is often caused by an inherited mutation in the gene for
the ryanodine receptor (RYR1) that resides in the
membrane of the sarcoplasmic reticulum. The gold standard for determination
of MH susceptibility is the caffeine-halothane contracture test. However,
it is invasive, requiring skeletal muscle biopsy and is not widely available.
Researchers have begun to map mutations within the ryanodine receptor gene
(chromosome 19q13.1) responsible for conferring MH susceptibility. Ryanodine
receptor mutations are found in at least 25% of known MH susceptible individuals
in North America. Mutation analysis has recently become available
in the United States and is expected to play an integral role in the diagnosis
of MH susceptibility in the future.
Litman RS, Rosenberg H. Malignant HyperthermiaUpdate on Susceptibility Testing. JAMA. 2005;293(23):2918-2924. doi:10.1001/jama.293.23.2918