MALIGNANT HYPERTHERMIA

Malignant hyperthermia is a rare autosomal dominant trait that predisp oses affected individuals to great danger when exposed to certain anae sthetic triggering agents (such as potent volatile anaesthetics and su ccinylcholine). A sudden hypermetabolic reaction in skeletal muscle le ading to hyperthermia and massive rhabdomyolysis can occur. The ultima te treatment is dantrolene sodium a nonspecific muscle relaxant. Certa in precautions should be taken before anaesthesia of patients known to be susceptible to malignant hyperthermia. These include the prohibiti on of the use of triggering agents, monitoring of central body tempera ture and expired CO2, and immediate availability of dantrolene. In add ition, careful cleansing of the anaesthesia machine of vapours of halo genated agents is recommended. If these measures are taken, the chance s of an MH episode are greatly reduced. When malignant hyperthermia-do es occur in the operating room, prompt recognition and treatment usual ly prevent a potentially fatal outcome. The most reliable test to esta blish susceptibility to malignant hyperthermia is currently the in vit ro caffeine-halothane contracture test. It is hoped that in the future a genetic test will be available.