what is malignant hypothermia

Malignant hyperthermia (MH) is a severe reaction that can occur in response to certain medications used during general anesthesia. It is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane, and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stresses such as vigorous exercise and heat. Symptoms of MH include muscle rigidity, fever, a fast heart rate, increased carbon dioxide production, increased oxygen consumption, mixed acidosis, rigid muscles, and rhabdomyolysis. These signs can develop any time during the administration of the anesthetic triggering agents, and rarely, signs may develop up to 40 minutes after the end of anesthesia. In most cases, no signs or symptoms of susceptibility to malignant hyperthermia exist until the person is exposed to certain drugs used for anesthesia. Treatments for malignant hyperthermia include the medication dantrolene, ice packs, and other measures to cool body temperature, as well as supportive care. Wrapping the person in a cooling blanket can help reduce fever and the risk for serious complications. To preserve kidney function during an episode, the person may receive fluids through a vein. Repeated or untreated episodes can cause kidney failure, and untreated episodes can be fatal.