Malignant hyperthermia is a rare inherited disorder in which a patient has a severe, life-threatening reaction when anesthesia gases are inhaled or a muscle relaxant called succinylcholine is given. When a patient who has the malignant hyperthermia gene has a reaction, his temperature rises rapidly, his muscles become rigid and the body begins to break down muscle fibers. The condition is serious and can result in the death of healthy patients if doctors cannot halt or control the symptoms with medication.
Testing is available for malignant hyperthermia and is recommended prior to surgery if close relatives have been diagnosed with the disorder. A muscle biopsy, a procedure where a small piece of muscle is removed by inserting a needle into a muscle, must be taken and analyzed to determine if a patient is a carrier.