National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Malignant hyperthermia



Other Names:
MH; Anesthesia related hyperthermia; Malignant hyperpyrexia; MH; Anesthesia related hyperthermia; Malignant hyperpyrexia; Fulminating hyperpyrexia; Pharmacogenic myopathy; Hyperpyrexia malignant; Hyperthermia of anesthesia; Malignant hyperthermia of anesthesia See More
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Malignant hyperthermia (MH) is a severe reaction to certain gases used during anesthesia and/or a muscle relaxant used to temporarily paralyze a person during surgery. Signs and symptoms of MH include marked hyperthermia, a rapid heart rate, rapid breathing, acidosis, muscle rigidity, and breakdown of muscle tissue (rhabdomyolysis). Without prompt treatment, MH can be life-threatening. People who are at increased risk for this reaction are said to have MH susceptibility. Susceptibility to MH may be caused by mutations in any of several genes and is inherited in an autosomal dominant manner. People with certain inherited muscle diseases (e.g., central core disease and multiminicore disease) also have MH susceptibility.[1][2]
Last updated: 6/30/2014

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
30%-79% of people have these symptoms
Cardiomyocyte mitochondrial proliferation 0031320
Fever 0001945
Hypercapnia
High blood carbon dioxide level
0012416
Hyperphosphatemia
High blood phosphate levels
0002905
Intermittent painful muscle spasms 0011964
Malignant hyperthermia 0002047
Metabolic acidosis 0001942
Muscle stiffness 0003552
Supraventricular tachycardia 0004755
Tachypnea
Increased respiratory rate or depth of breathing
0002789
Ventricular tachycardia 0004756
5%-29% of people have these symptoms
Abnormality of masseter muscle 3000005
Abnormality of the coagulation cascade 0003256
Acute hepatic failure
Acute liver failure
0006554
Acute kidney injury 0001919
Acute rhabdomyolysis 0008942
Elevated creatine kinase after exercise 0008331
Exercise-induced rhabdomyolysis 0009045
High-output congestive heart failure 0001722
Hyperkalemia
Elevated serum potassium levels
0002153
Myoglobinuria 0002913
Necrotizing myopathy 0008978
Ventricular extrasystoles
Extra heart beat
0006682
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Last updated: 7/1/2020

While malignant hyperthermia itself is not inherited, malignant hyperthermia susceptibility (MHS) is inherited in an autosomal dominant manner. This means that having a mutation in only one copy of the responsible gene is enough to make someone susceptible to having malignant hyperthermia.

Most people diagnosed with malignant hyperthermia or MHS have a parent with MHS; however, the parent may not have experienced an episode of malignant hyperthermia. Therefore, the family history may appear to be negative when other family members are susceptible. In some cases, a person with MHS is affected due to having a new (de novo) mutation that was not inherited from a parent. Parents of a person with an apparently new mutation may be evaluated by having contracture testing (a muscle biopsy to determine susceptibility) or molecular genetic testing, if the mutation in the affected person is known.

Each child of a person with MHS has a 50% (1 in 2) risk to inherit MHS.

The risks to siblings of an affected person depend on whether the affected person has a new mutation or inherited MHS from a parent. If a parent has MHS, each sibling as a 50% (1 in 2) risk to have MHS. When both parents appear unaffected based on evaluation, the risk to siblings of an affected person appears to be low.

The risk to other family members of an affected person also depend on whether an affected person's parent has the condition. If a parent also has MHS, other family members are at risk.[3]

People interested in learning about specific genetic risks to themselves or family members should speak with a genetics professional.
Last updated: 6/30/2014

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Management Guidelines

  • The European Malignant Hyperthermia Group has established guidelines for molecular genetic testing of malignant susceptibility and for in-vitro contracture testing. To read more, click on the link.
  • Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.  
  • Project OrphanAnesthesia is a project whose aim is to create peer-reviewed, readily accessible guidelines for patients with rare diseases and for the anesthesiologists caring for them. The project is a collaborative effort of the German Society of Anesthesiology and Intensive Care, Orphanet, the European Society of Pediatric Anesthesia, anesthetists and rare disease experts with the aim to contribute to patient safety.

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.


If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
The differential diagnosis of a fulminant MH crisis includes sporadic pheochromocytoma, serotonin syndrome, neuroleptic malignant syndrome (see these terms), anaphylactic reaction, thyroid crisis and sepsis.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Malignant hyperthermia. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Malignant hyperthermia. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) lists the subtypes and associated genes for Malignant hyperthermia in a table called Phenotypic Series. Each entry in OMIM includes a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Malignant hyperthermia. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • Is the health of a person with malignant hyperthermia only jeopardized when anesthesia is used or are there daily complications that a person with this condition has to endure if they don't receive some sort of treatment? See answer

  • My brother has malignant hyperthermia. What are the chances his parents, siblings, children, nieces, and nephews will have it? See answer

  • Can malignant hyperthermia be transferred by blood donations? And at what age up to can you still donate blood? See answer



  1. Malignant Hyperthermia. Genetics Home Reference. 2007; http://ghr.nlm.nih.gov/condition/malignant-hyperthermia. Accessed 4/4/2011.
  2. Mark Davis, Danielle James, Neil Pollock, Henry Rosenberg, Kathryn Stowell. Malignant hyperthermia. Orphanet. April, 2007; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=423. Accessed 6/30/2014.
  3. Henry Rosenberg, Nyamkhishig Sambuughin, Sheila Riazi, and Robert Dirksen. Malignant hyperthermia susceptibility. GeneReviews. January 31, 2013; http://www.ncbi.nlm.nih.gov/books/NBK1146/. Accessed 6/30/2014.