Medicine: Inherited Hazard

Anesthetics can be given safely to most surgical patients. But for a small minority, anesthesia can trigger a rare hereditary disorder called malignant hyperthermia — a potentially lethal rise in body temperature. A group of Boston doctors reported recently in the New England Journal of Medicine that malignant hyperthermia can be brought under control by use of a heart-lung machine to cool the blood. But the condition can also be avoided by presurgical testing. Researchers have identified the genetic defect that causes the ailment and have devised a means of identifying victims: exposing a small sample of a patient’s muscle tissue to halothane or other anesthetic drugs. If the defect is present, the muscle contracts abnormally. In families with a his tory of malignant hyperthermia, the complex test is well worth the trouble. Without prompt treatment, the condition is fatal in six out often cases.