Most people with malignant hyperthermia are not diagnosed until they have a serious reaction to general anesthesia. Doctors usually will suspect this condition if a patient develops typical symptoms, especially very high fever and rigid muscles.
Blood tests that show changes in the body chemistry hint at malignant hyperthermia. These include high levels of the muscle enzyme CPK (creatine phosphokinase) and electrolyte changes. Blood tests that show signs of kidney failure also can provide clues. If malignant hyperthermia is not recognized and treated quickly, the person's heart may stop during surgery.
If you experience most or all of the typical symptoms of malignant hyperthermia, your doctor may diagnose this condition without additional testing.