Malignant Hyperthermia

What is Malignant Hyperthermia?

Malignant hyperthermia is a rare inherited disease that causes rapid onset of extremely high body temperature associated with muscle rigidity and muscle injury in people exposed to certain types of anesthesia. It often occurs in the operating room during surgery, or in the recovery room.

What causes Malignant Hyperthermia?

Malignant hyperthermia is triggered by gaseous, inhaled anesthetics, and/or muscle relaxants used during surgery, which cause a chain of events within the body of a susceptible person. The chain reaction starts when the presence of the anesthetic initiates the release of calcium within muscles. In patients with gene mutations that affect the sensitivity and release of calcium in the muscle cells, the level of calcium increases excessively in the muscle cells. These high levels increase metabolism and also cause the muscle to contract and stay contracted, which results in production of heat, acidosis, and muscle cell breakdown.

How is Malignant Hyperthermia diagnosed?

Malignant hyperthermia is diagnosed by muscle biopsy and contracture testing or by molecular genetic testing. The latter is not always diagnostic.

How is Malignant Hyperthermia treated?

Prevention is the key to malignant hyperthermia. Patients should be sure to tell their doctors if they or someone in their family has had a similar reaction to anesthesia in the past. The best way to ensure full recovery of malignant hyperthermia is by identifying that it exists early on. Once that is done, the drug dantrolene sodium is given to treat and reduce the symptoms.

More Information

Malignant Hyperthermia Association of the US