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Learning About Malignant Hyperthermia

What is malignant hyperthermia?

Malignant hyperthermia is a rare, life-threatening reaction to some drugs used during surgery or other procedures. These drugs include medicines to make you unconscious. They also include medicines to help your muscles relax. The reaction can happen during or after surgery.

What causes it?

It's triggered by certain drugs that are used during general anesthesia. It's most likely to happen to people who have a rare problem that may be passed down in families.

What are the symptoms?

The first signs are high levels of carbon dioxide in the blood and a fast heart rate. Other severe reactions can also happen. You may have stiff muscles and a very high body temperature. Muscle tissue can break down as well.

How is it treated?

Doctors and nurses who give anesthesia watch closely for the first signs of the condition. They can treat it right away.

Treatment includes stopping the drugs that caused the reaction. It also includes giving medicines. Your body may also be cooled down. Usually the surgery has to be stopped. You may need to stay in the hospital for a few days after the surgery.

What increases your risk?

Malignant hyperthermia is more likely if you or a family member has had it before. Your risk is higher if you have a disease that affects the muscles. You can have a test to find out if you're at risk.

What can you do if you think it might happen to you?

If you think you might be at risk, tell your surgeon and anesthesia provider before surgery. They can use different drugs to make you unconscious. They can also prepare to treat you right away if needed.

Wear a medical ID bracelet that says you are at risk. If you need emergency care, the bracelet will inform those who treat you. And warn your family members. They might be at risk too.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

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