- Malignant Hyperthermia Center
- Fat-Fighting Foods Slideshow
- Take the Human Body Quiz
- Causes of Fatigue Slideshow Pictures
- Find a local Doctor in your town
- Malignant hyperthermia facts*
- What is malignant hyperthermia?
- How common is malignant hyperthermia?
- What genes are related to malignant hyperthermia?
- How do people inherit malignant hyperthermia?
- Where can I find information about diagnosis, management, or treatment of malignant hyperthermia?
- What other names do people use for malignant hyperthermia?
Malignant hyperthermia facts*
*Malignant hyperthermia facts medical author: Melissa Conrad Stöppler, MD
- Malignant hyperthermia is a severe reaction to particular drugs that are often used during general anesthesia for surgery.
- Malignant hyperthermia occurs in 1 in 5,000 to 50,000 instances in which people are given anesthetic gases.
- Muscle rigidity, breakdown of muscle fibers (rhabdomyolysis), a high fever, increased acid levels in the blood and other tissues (acidosis), and a rapid heart rate are some of the effects of this potentially life-threatening condition.
- Researchers have described at least six forms of malignant hyperthermia susceptibility, which are caused by mutations in different genes. For example, variations of the CACNA1S and RYR1 genes increase the risk of developing malignant hyperthermia.
- Malignant hyperthermia susceptibility is inherited in an autosomal dominant manner (which means that one copy of the altered gene in each cell is sufficient to increase the risk of the condition).
What is malignant hyperthermia?
Malignant hyperthermia is a severe reaction to particular drugs that are often used during surgery and other invasive procedures. Specifically, this reaction occurs in response to some anesthetic gases, which are used to block the sensation of pain, and with a muscle relaxant that is used to temporarily paralyze a person during a surgical procedure. If given these drugs, people at risk for malignant hyperthermia may experience muscle rigidity, breakdown of muscle fibers (rhabdomyolysis), a high fever, increased acid levels in the blood and other tissues (acidosis), and a rapid heart rate. Without prompt treatment, the complications of malignant hyperthermia can be life-threatening.
People at increased risk for this disorder are said to have malignant hyperthermia susceptibility. Affected individuals may never know they have the condition unless they undergo testing or have a severe reaction to anesthesia during a surgical procedure. While this condition often occurs in people without other serious medical problems, certain inherited muscle diseases (including central core disease and multiminicore disease) are associated with malignant hyperthermia susceptibility.
Quick Guide8 First Aid Kit Essentials for Scrapes, Cuts, Bug Bites, and More in Pictures
How common is malignant hyperthermia?
Malignant hyperthermia occurs in 1 in 5,000 to 50,000 instances in which people are given anesthetic gases. Susceptibility to malignant hyperthermia is probably more frequent, because many people with an increased risk of this condition are never exposed to drugs that trigger a reaction.
What genes are related to malignant hyperthermia?
Variations of the CACNA1S and RYR1 genes increase the risk of developing malignant hyperthermia.
Researchers have described at least six forms of malignant hyperthermia susceptibility, which are caused by mutations in different genes. Mutations in the RYR1 gene are responsible for a form of the condition known as MHS1. These mutations account for most cases of malignant hyperthermia susceptibility. Another form of the condition, MHS5, results from mutations in the CACNA1S gene. These mutations are less common, causing less than 1 percent of all cases of malignant hyperthermia susceptibility.
The RYR1 and CACNA1S genes provide instructions for making proteins that play essential roles in muscles used for movement (skeletal muscles). For the body to move normally, these muscles must tense (contract) and relax in a coordinated way. Muscle contractions are triggered by the flow of certain charged atoms (ions) into muscle cells. The proteins produced from the RYR1 and CACNA1S genes are involved in the movement of calcium ions within muscle cells. In response to certain signals, the CACNA1S protein helps activate the RYR1 channel, which releases stored calcium ions within muscle cells. The resulting increase in calcium ion concentration inside muscle cells stimulates muscle fibers to contract.
Mutations in the RYR1 or CACNA1S gene cause the RYR1 channel to open more easily and close more slowly in response to certain drugs. As a result, large amounts of calcium ions are released from storage within muscle cells. An overabundance of available calcium ions causes skeletal muscles to contract abnormally, which leads to muscle rigidity in people with malignant hyperthermia. An increase in calcium ion concentration within muscle cells also activates processes that generate heat (leading to increased body temperature) and produce excess acid (leading to acidosis).
The genetic causes of several other types of malignant hyperthermia (MHS2, MHS4, and MHS6) are still under study. A form of the condition known as MHS3 has been linked to the CACNA2D1 gene. This gene provides instructions for making a protein that plays an essential role in activating the RYR1 channel to release calcium ions into muscle cells. Although this gene is thought to be related to malignant hyperthermia in a few families, no causative mutations have been identified.
How do people inherit malignant hyperthermia?
Malignant hyperthermia susceptibility is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to increase the risk of a severe reaction to certain drugs used during surgery. In most cases, an affected person inherits the altered gene from a parent who is also at risk for the condition.
Where can I find information about diagnosis, management, or treatment of malignant hyperthermia?
These resources address the diagnosis or management of malignant hyperthermia and may include treatment providers.
- Gene Review: Malignant Hyperthermia Susceptibility.
- Gene Tests: CACNA1S-Related Malignant Hyperthermia Susceptibility.
- Gene Tests: MHS2-Related Malignant Hyperthermia Susceptibility.
- Gene Tests: MHS3-Related Malignant Hyperthermia Susceptibility.
- Gene Tests: MHS4-Related Malignant Hyperthermia Susceptibility.
- Gene Tests: RYR1-Related Malignant Hyperthermia Susceptibility.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook. Where can I find additional information about malignant hyperthermia?
What other names do people use for malignant hyperthermia?
- anesthesia related hyperthermia
- Hyperpyrexia, Malignant
- Hyperthermia, Malignant
- Malignant Hyperpyrexia
- MHS - Malignant hyperthermia
Top Malignant Hyperthermia Related Articles
Genetic CounselingYour health care provider may refer you to a genetic professional. Universities and medical centers also often have affiliated genetic professionals, or can provide referrals to a genetic professional or genetics clinic. Genetic counseling provides patients and family members the tools to make the right choice in regard to test for a disease or condition.
The definition of a genetic disease is a disorder or condition caused by abnormalities in a person's genome. Some types of genetic inheritance include single inheritance, including cystic fibrosis, sickle cell anemia, Marfan syndrome, and hemochromatosis. Other types of genetic diseases include multifactorial inheritance. Still other types of genetic diseases include chromosome abnormalities (for example, Turner syndrome, and Klinefelter syndrome), and mitochondrial inheritance (for example, epilepsy and dementia).
RhabdomyolysisRhabdomyolysis is a rapid deterioration and destruction of skeletal muscle. Some of the causes of rhabdomyolysis include:
- severe burns,
- muscle trauma,
- electrolyte imbalance,
- medications (statins),
- viruses, and
Sinus SurgerySinus surgery involves the precise removal of diseased sinus tissue with the improvement in the natural drainage channels by the creation of a pathway for infected material to drain from the sinus cavities. The sinus surgery information is provided to help you prepare for sinus surgery and to help you understand more clearly the associated benefits, risks, and complications.
Surgery QuestionsSurgery is the branch of medicine that employs operations in the treatment of disease or injury. Prior to surgery you might consider asking your surgeon questions about the operation (procedure).
Surgical SterilizationSurgical sterilization is considered a permanent method of contraception. In certain cases, sterilization can be reversed, but this is not guaranteed. For this reason, sterilization is meant for men and women who do not intend to have children in the future. Types of surgical sterilization include: vasectomy, tubal ligation, STOP (selective tubal occlusion procedure), and hysterectomy.
Temporal Lobe ResectionThe largest part of the brain, the cerebrum, is divided into four paired sections—the frontal, parietal, occipital, and temporal lobes. Each lobe controls a specific group of activities. The temporal lobe, located on either side of the brain just above the ear, plays an important role in hearing, language, and memory. In people with temporal lobe epilepsy, the area where the seizures start -- called the seizure focus -- is located within the temporal lobe.
Total Knee ReplacementDuring total knee replacement surgery, the diseased knee joint is replaced with artificial material. The risks include blood clots in the legs, urinary tract infection, nausea and vomiting, chronic knee pain, nerve damage, and infection.
TracheostomyA tracheostomy is a surgically created opening in the neck leading directly to the trachea (the breathing tube). It is maintained open with a hollow tube called a tracheostomy tube. Tracheostomies are used to:
- bypass an obstructed airway,
- remove airway secretions, and
- easily deliver oxygen to the lungs.
Tummy Tuck ( Abdominoplasty)This surgical procedure involves the removal of excess fat and skin from the abdomen. A tummy tuck also involves tightening the muscles of the abdominal wall. Complications and side effects of the procedure include pain, swelling, numbness, bruising, and tiredness. Potential side effects include infection, bleeding, blood clots, insufficient healing, and scarring.
VasectomyA vasectomy is a simple surgical procedure used as a permanent form of male birth control. The odds of pregnancy after a vasectomy are low and the side effects are few. Although the procedure can be reversed, it is usually difficult, expensive, and unsuccessful.