Malignant Hyperthermia

Malignant hyperthermia (MH) is a rare hereditary disease that causes a rapid rise in body temperature (fever) and intense muscle contractions that is triggered when the susceptible person receives general anesthesia. This condition should not be confused with hyperthermia due to medical emergencies, such as heat stroke or infection.

Symptoms include:

• Bleeding
• Dark brown urine
• Muscle pain without an obvious cause, such as exercise or injury
• Muscle tightness and stiffness
• Rapid rise in temperature
• Eyelid myotonia (a condition in which after opening and closing the eyes, they cannot be opened again for a short time)

The use of certain medications such as dantrolene may prevent the complications of malignant hyperthermia during surgery.

Stimulant drugs such as cocaine, amphetamines (stimulants), and ecstasy should be avoided because they can cause problems similar to malignant hyperthermia in people who are prone to this condition.

Anyone who suffers from myopathy (caused by defects in any of the MH susceptibility genes such as RYR1, CACNA1S, STAC3), rhabdomyolysis, hyperkalemia of unknown origin, or who is a carrier of pathogenic variants in these genes or has family members with MH susceptibility genes such as RYR1, CACNA1S, STAC3.It is recommended to seek genetic counseling and inform your physician and anesthesiologist if you are a carrier of pathogenic variants in these genes or have blood relatives who are carriers and/or have suffered an MH reaction.