Malignant Hyperthermia – Diagnosis and Treatment
Diagnosis
Screening for Increased Risk
Doctors often perform specific tests to check if someone is at higher risk for malignant hyperthermia (MH).
This is especially important if there’s a family history of MH, past episodes of muscle rigidity after anesthesia, or symptoms like high body temperature, sweating, fast heartbeat, or unexplained acidosis after exposure to certain anesthesia drugs.
Genetic Evaluation
Genetic testing checks for susceptibility. Medical staff collect a blood sample and send it to a lab, where experts look for changes in genes linked to MH.
If they find a certain mutation, it shows that the person has MH susceptibility (MHS), a genetic disease related to abnormal calcium release in skeletal muscle. This testing helps family members of patients who experienced symptoms during anesthesia.
Muscle Biopsy (Contracture) Test
A muscle biopsy, also called a contracture test, is another way to check susceptibility. Surgeons take a small piece of muscle and quickly send it to a special lab.
There, specialists expose it to MH-triggering substances like specific anesthetics. If the muscle overreacts or contracts more than normal, this suggests MH susceptibility. Doctors often use this test when genetic test results are unclear.
Key Signs and Lab Findings:
| Symptom/Lab | Possible Indication for MH Susceptibility |
|---|---|
| Muscle rigidity | Yes |
| Rise in body temperature | Yes |
| Metabolic/respiratory acidosis | Yes |
| Increased creatine kinase | Yes |
| Rhabdomyolysis | Possible |
| Hypercapnia/Oxygen use | Yes |
| Hyperkalemia, tachycardia | Yes |
| Myoglobin in blood/urine | Yes |
Doctors use these tests to prevent future crises by identifying people who should avoid certain anesthesia drugs that can trigger MH.
Treatment
Medical teams must act quickly and carefully to protect patients with malignant hyperthermia. The main goals are to stop the dangerous reaction, lower body temperature, and prevent serious problems like kidney injury.
Key steps in medical care:
Muscle Relaxant: Doctors use a calcium release inhibitor as the main treatment. It blocks calcium from entering the muscles, helping them relax and stopping the dangerous reaction. Medical staff give it right away through an intravenous (IV) line and monitor the dose closely to avoid side effects like confusion, trouble breathing, or liver problems.
High Flow Oxygen: Medical staff give patients 100% oxygen, usually by a face mask or a tube in the windpipe. This removes extra carbon dioxide from the body.
Lowering Body Temperature: Medical teams put ice packs under the arms and in the groin, use cooling blankets, fans, or give cold fluids through an IV to cool the body.
Fluids and Electrolytes: Medical staff give more fluids through an IV to prevent dehydration and kidney failure. Sometimes, they use other medicines such as bicarbonate to correct acid levels in the blood.
Supportive Monitoring: Patients go to intensive care for careful monitoring. Health workers check temperature, breathing, heartbeat, blood pressure, and urine. Lab tests show if muscle breakdown threatens the kidneys.
| Treatment Part | Purpose | Medicine or Action |
|---|---|---|
| Muscle Relaxant | Stop muscle overactivity | Calcium release inhibitor |
| Oxygen Therapy | Lower extra CO2 and support breathing | 100% Oxygen |
| Body Cooling | Lower high body temperature | Ice, Cooling Blankets |
| Extra Fluids | Protect kidneys and balance fluids | IV Fluids |
| Chemical Balance | Correct acid/base and potassium levels | Bicarbonate (If Needed) |
| Supportive Care | Watch for new problems | ICU Monitoring |
Steps To Take After Hospital Care
After the crisis, patients need to take long-term steps for safety.
Patients should talk to their doctor about risks during future surgeries. They should avoid medicines that can trigger malignant hyperthermia. Sometimes, doctors use total intravenous anesthesia (TIVA) instead of gas anesthesia to prevent another reaction.
Doctors may recommend genetic testing to determine if the patient or family members have a risk for malignant hyperthermia. Wearing a medical alert bracelet or necklace warns care teams about the risk in any emergency.
During very hot and humid weather, patients should take extra care. They should ask their doctor about which activities are safe. Regular follow-up visits allow doctors to check for any late side effects and kidney issues from the reaction.
Get Ready for Your Visit
If you or a loved one are being evaluated for malignant hyperthermia, it’s important to prepare ahead of time.
What to bring:
- A detailed family history, especially related to complications from anesthesia or unexplained high fevers during surgeries.
- Records of any past anesthesia use, surgeries, or reactions.
- A list of symptoms such as muscle stiffness, rapid heartbeat, or unexpected temperature changes.
- All current medications, supplements, and allergies.
What to ask your doctor:
- What kind of testing do I need—genetic or muscle biopsy?
- How will this affect future surgeries or medical procedures?
- Should my family members be tested?
- What precautions do I need to take in emergencies or while exercising?
Having a trusted friend or family member at your appointment can help you remember details and ask questions. Taking notes or requesting a summary from your provider can also help you follow your care plan and avoid triggers in the future.
