Malignant hyperthermia: current perspectives

The incidence, etiology, clinical manifestations, and management of malignant hyperthermia (MH) are reviewed. The syndrome of MH is recognized as one of the causes of anesthesia-related deaths. It is considered pharmacogenetic because both an abnormal gene and precipitating environmental factors are necessary to produce an acute reaction. Metabolic defects, involving a derangement of calcium dynamics, appear to be the common characteristic of susceptible individuals. Calcium release and uptake from the sarcoplasmic reticulum is altered when an individual with MH is exposed to certain anesthetic agents or triggering physical and emotional stresses. Muscle rigidity, tachycardia, tachypnea, and high fever can lead to other complications and death. Management of an acute reaction of MH includes cooling methods to lower body temperature, hyperventilation, sodium bicarbonate control of acidosis, maintenance of fluid and electrolyte balance, and the administration of dantrolene sodium. A thorough family history, baseline CPKs, caffeine-halothane contracture tests, and ultramicroscopic examination of muscle biopsy specimens are recommended as screening techniques. The early administration of dantrolene sodium in acute reaction of MH has been shown to rapidly alleviate the symptoms and ensuing severe complications. Individuals with a strong family history of MH or previous episodes may be treated with oral dantrolene sodium before surgery to effectively prevent a crisis, and after surgery to prevent recurrence.