Overview

Malignant hyperthermia is a severe reaction to certain drugs used for anesthesia. This severe reaction typically includes a dangerously high body temperature, rigid muscles or spasms, a rapid heart rate, and other symptoms. Without prompt treatment, the complications caused by malignant hyperthermia can be fatal.

In most cases, the defective gene that puts you at risk of malignant hyperthermia is inherited, though sometimes it's the result of a random genetic defect. Genetic testing can reveal whether you have an abnormal gene. This genetic disorder is called malignant hyperthermia susceptibility (MHS).

Treatments for malignant hyperthermia include the medication dantrolene (Dantrium, Ryanodex, Revonto), ice packs and other measures to cool body temperature, as well as supportive care.