Malignant Hyperthermia

Diagnosis

The diagnosis of malignant hyperthermia relies on the observation of signs and symptoms, continuous monitoring during and immediately after anesthesia, and laboratory tests aimed at identifying potential complications. 

Susceptibility testing

Testing for an elevated risk of malignant hyperthermia (susceptibility testing) may be advised if you possess risk factors. This testing can involve either genetic testing or a muscle biopsy test. 

• Genetic testing: The identification of the gene change (mutation) associated with malignant hyperthermia susceptibility is accomplished through genetic testing. A blood sample is collected and sent to a laboratory for analysis. This form of testing can pinpoint the gene alteration indicative of the genetic disorder known as malignant hyperthermia susceptibility (MHS). 
• Muscle biopsy (contracture test): If there is a risk of malignant hyperthermia, your doctor might recommend a muscle biopsy. In this procedure, a small segment of muscle tissue is surgically extracted for laboratory examination. The specimen undergoes exposure to triggering chemicals for malignant hyperthermia, assessing how the muscle contracts. As this test necessitates immediate analysis on the muscle tissue, it requires travel to a specialized muscle biopsy center. 

Treatment

If you or a family member is susceptible to MHS, or you believe you may be at risk, it is crucial to inform your doctor and anesthesiologist before undergoing anesthesia. Anesthesia plans can be adjusted to include drugs that do not trigger malignant hyperthermia.

Immediate treatment for malignant hyperthermia involves the following measures:

• Medication: Dantrolene is administered to halt the release of calcium into muscles, addressing the reaction. Other medications may be given to correct metabolic imbalances and treat complications.
• Oxygen: Oxygen may be administered through a face mask or a tube inserted into the windpipe (trachea).
• Body cooling: Various methods, such as ice packs, cooling blankets, a fan with cool mist, and chilled Intravenous (IV) fluids, are employed to reduce body temperature.
• Extra fluids: Additional fluids may be administered through an intravenous (IV) line.
• Supportive care: Intensive care monitoring in the hospital is often necessary for a day or two. This involves tracking temperature, blood pressure, heart rate, breathing, and response to treatment. Frequent lab tests assess muscle breakdown and potential kidney damage. Hospitalization typically continues until lab results return to standard ranges.

With prompt treatment, malignant hyperthermia typically resolves within a few days.