Malignant Hyperthermia

Malignant hyperthermia is also known as malignant hyperpyrexia. It is a rare and life-threatening condition, which is triggered by exposure to certain drugs such as anesthesia which are administered while performing surgeries. In malignant hyperthermia your body temperature rises and you may also experience severe muscle contractions.The condition requires a prompt treatment, without which the disease can be fatal. This condition is caused by the rare inherited abnormality in the muscles.

Signs and symptoms

Malignant hyperthermia symptoms include a very high body temperature, sometimes as high as 113F, severe muscle spasms (especially in the jaw) and an abnormally rapid heartbeat. In few cases, signs of malignant hyperthermia are seen after an intense physical activity or heat stroke. In some cases, the people with inherited malignant hyperthermia may remain asymptomatic.

Some of the other symptoms of malignant hyperthermia include flushed skin, sweating, rapid breathing, brown or amber colored urine, very low blood pressure, confusion and muscle weakness.


The main cause of malignant hyperthermia is the inheritance of the abnormal genes. This condition sometimes occurs in people with muscular dystrophy. It may also occur in the people with other muscle diseases that are associated with genetic mutations. More or less malignant hyperthermia is also caused by strenuous physical activity and heat stroke.

Risk factors

If you have a close relation with the patient (such as if you are a parent, sibling or child) diagnosed with malignant hyperthermia, there is a 50 percent chance that you have the condition as well. If you are other close relative (such as aunt, uncle, or grandchild) of the person with malignant hyperthermia, then you may have a 25 percent chance of inheriting the condition.

Men are more likely to have malignant hyperthermia compared to women. Children are also susceptible to reactions during surgery.


Complications may develop if a severe reaction develops even after treatment is started. These complications include respiratory or kidney failure. If these complications do not improve within days or weeks, then there may be a permanent damage to the organs. It can be more fatal without appropriate treatment.

There may also be complications such as metabolic acidosis, abnormal clotting and bleeding, breakdown of muscle tissue, and even death in severe stages.



The condition of malignant hyperthermia is left undiagnosed until it has a serious reaction to general anesthesia. Your doctor will suspect the condition if you start developing all the typical symptoms such as very high fever and rigid muscles

Blood tests that show high levels of the muscle enzyme creatine phosphokinase (CPK) and electrolyte changes indicate malignant hyperthermia. Blood tests that identify signs of kidney failure also indicate malignant hyperthermia.

If you show up the most typical symptoms of malignant hyperthermia, then it is easy for your doctor to diagnose the condition without the use of any additional diagnostic tests.


The first and the most important step in the treatment for malignant hyperthermia is to immediately stop the triggering medication. Your doctor may then administer the drug dantrolene intravenously until you are stabilized. Dantrolene acts by relaxing the muscles by stopping the dangerous increase in muscle metabolism. It is continued in pill form for three days once you are stabilized.

Other treatment options include:

  • Administering oxygen
  • Using medications to control the heart beat and blood pressure
  • Reducing the body temperature by using cool mist or fans, chilled intravenous fluids etc.

Prevention or self- management

Early treatment at the onset of symptoms is usually successful. Once the condition is recognized and diagnosed, future episodes can almost always be prevented by avoiding known triggers.