BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuMalignant hyperthermiaHyperthermia - malignant; Hyperpyrexia - malignant; MHMalignant hyperthermia (MH) is a disease that causes a fast rise in body temperature and severe muscle contractions when someone receives general anesthesia with one or more of the following medicines: isoflurane, sevoflurane, desflurane or succinylcholine. MH is a genetic disorder passed down through families.General anesthesiaGeneral anesthesia is treatment with certain medicines that puts you into a deep sleep-like state so you do not feel pain during surgery. After you ...Read Article Now Book Mark Article Hyperthermia means high body temperature. Malignant hyperthermia is not the same as hyperthermia from other medical emergencies such as heat stroke or infection.Heat strokeHeat emergencies or illnesses are caused by exposure to extreme heat or sun. Heat illnesses can be prevented by being careful in hot, humid weather....Read Article Now Book Mark Article Causes MH is inherited. Only one parent has to carry the gene for the disease for a child to inherit the condition.It may occur with some other inherited muscle diseases, such as multiminicore myopathy and central core disease. Symptoms Symptoms of MH include:Bleeding Dark brown urine (due to a muscle protein called myoglobin in the urine) Muscle aches without an obvious cause, such as exercise or injury Muscle rigidity and stiffness Muscle rigidityMuscle cramps are when a muscle gets tight (contracts) without you trying to tighten it, and it does not relax. Cramps may involve all or part of on...Read Article Now Book Mark Article Rise in body temperature to 105°F (40.6°C) or higher Exams and Tests MH is often discovered after a person is given anesthesia during surgery.There may be a family history of MH or unexplained death during anesthesia.The person may have a fast and often irregular heart rate.Irregular heart rateAn arrhythmia is a disorder of the heart rate (pulse) or heart rhythm. The heart can beat too fast (tachycardia), too slow (bradycardia), or irregul...Read Article Now Book Mark Article Tests for MH may include:Blood clotting studies (PT, or prothrombin time; PTT, or partial thromboplastin time) PT, or prothrombin timeProthrombin time (PT) is a blood test that measures the time it takes for the liquid portion (plasma) of your blood to clot. It measures the functio...Read Article Now Book Mark Article PTT, or partial thromboplastin timeProthrombin time (PT) is a blood test that measures the time it takes for the liquid portion (plasma) of your blood to clot. It measures the functio...Read Article Now Book Mark Article Blood chemistry panel, including CK (creatine kinase, which is higher in the blood when muscle is destroyed during a bout of the illness) Genetic testing to look for defects in the genes that are linked with the disease Genetic testingPharmacogenetic testing provides information about your genes and how they control your response to certain medicines. Your genes can affect the des...Read Article Now Book Mark Article Muscle biopsy Muscle biopsyA muscle biopsy is the removal of a small piece of muscle tissue for examination.Read Article Now Book Mark Article Urine myoglobin (testing for muscle protein in the urine) Urine myoglobinThe myoglobin urine test is done to detect the presence of myoglobin in urine. Myoglobin can also be measured with a blood test.Read Article Now Book Mark Article Treatment During an episode of MH, a medicine called dantrolene is often given. Wrapping the person in a cooling blanket can help reduce fever and the risk for serious complications. To preserve kidney function during an episode, the person may receive fluids through a vein. Support Groups These resources can provide more information about MH:Malignant Hyperthermia Association of the United States -- www.mhaus.org National Organization for Rare Disorders -- rarediseases.org/rare-diseases/malignant-hyperthermia US National Library of Medicine - MedlinePlus website -- medlineplus.gov/genetics/condition/malignant-hyperthermia/ Outlook (Prognosis) Repeated or untreated episodes can cause kidney failure. Untreated episodes can be fatal. Possible Complications These serious complications can occur:Amputation Breakdown of muscle tissue Swelling of the hands and feet and problems with blood flow and nerve function (compartment syndrome) Compartment syndromeAcute compartment syndrome is a serious condition that involves increased pressure in a muscle compartment. It can lead to problems with blood flow ...Read Article Now Book Mark Article Death Abnormal blood clotting and bleeding Heart rhythm problems Kidney failure Buildup of acid in the body fluids (metabolic acidosis) Metabolic acidosisMetabolic acidosis is a condition in which there is too much acid in the body fluids.Read Article Now Book Mark Article Fluid buildup in the lungs Fluid buildup in the lungsPulmonary edema is an abnormal buildup of fluid in the lungs. This buildup of fluid leads to shortness of breath.Read Article Now Book Mark Article Weak or deformed muscles (myopathy or muscular dystrophy)Muscular dystrophyMuscular dystrophy (MD) is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.Read Article Now Book Mark Article When to Contact a Medical Professional If you need surgery, tell both your surgeon and anesthesiologist before surgery if:You know that you or a member of your family has had problems with general anesthesia You know you have a family history of MHUsing certain medicines can reduce or prevent the complications of MH during surgery. Prevention Tell your health care provider before having surgery with general anesthesia, if you or anyone in your family has MH. Avoid stimulant medicines and illicit drugs such as cocaine, amphetamine (speed), and ecstasy. They may cause problems similar to MH in people who are prone to this condition.Genetic counseling is recommended for anyone with a family history of myopathy, muscular dystrophy, or MH.Genetic counselingGenetics is the study of heredity, the process of a parent passing certain genes on to their children. A person's appearance, such as height, hair co...Read Article Now Book Mark Article Open ReferencesReferencesAmerican Association of Nurse Anesthesiology. Malignant hyperthermia crisis preparedness and treatment: position statement. 10. issuu.com/aanapublishing/docs/11_-_malignant_hyperthermia_crisis_preparedness_an. Updated April 2018. Accessed May 19, 2025.Yepuri N, Pruekprasert N, Cooney RN. Surgical complications. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 21st ed. St Louis, MO: Elsevier; 2022:chap 12.Zhou J, Zhao J, Yu X, Nozari A, Pessah IN, Allen PD. Neuromuscular disorders and other genetic disorders. In: Gropper MA, Cohen NH, Eriksson LI, Fleisher LA, Johnson-Akeju S, Leslie K, eds. Miller's Anesthesia. 10th ed. Philadelphia, PA: Elsevier; 2025:chap 31.AllVideoImagesTog Tests for Malignant hyperthermia Creatine phosphokinase testMyoglobin blood testMyoglobin urine testRelated Information Muscular dystrophy(Condition)Fever(Symptoms)Muscle cramps(Symptoms)Acute kidney failure(Condition)Rhabdomyolysis(Condition) Review Date: 5/19/2025 Reviewed By: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. 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Malignant hyperthermiaHyperthermia - malignant; Hyperpyrexia - malignant; MHMalignant hyperthermia (MH) is a disease that causes a fast rise in body temperature and severe muscle contractions when someone receives general anesthesia with one or more of the following medicines: isoflurane, sevoflurane, desflurane or succinylcholine. MH is a genetic disorder passed down through families.General anesthesiaGeneral anesthesia is treatment with certain medicines that puts you into a deep sleep-like state so you do not feel pain during surgery. After you ...Read Article Now Book Mark Article Hyperthermia means high body temperature. Malignant hyperthermia is not the same as hyperthermia from other medical emergencies such as heat stroke or infection.Heat strokeHeat emergencies or illnesses are caused by exposure to extreme heat or sun. Heat illnesses can be prevented by being careful in hot, humid weather....Read Article Now Book Mark Article Causes MH is inherited. Only one parent has to carry the gene for the disease for a child to inherit the condition.It may occur with some other inherited muscle diseases, such as multiminicore myopathy and central core disease. Symptoms Symptoms of MH include:Bleeding Dark brown urine (due to a muscle protein called myoglobin in the urine) Muscle aches without an obvious cause, such as exercise or injury Muscle rigidity and stiffness Muscle rigidityMuscle cramps are when a muscle gets tight (contracts) without you trying to tighten it, and it does not relax. Cramps may involve all or part of on...Read Article Now Book Mark Article Rise in body temperature to 105°F (40.6°C) or higher Exams and Tests MH is often discovered after a person is given anesthesia during surgery.There may be a family history of MH or unexplained death during anesthesia.The person may have a fast and often irregular heart rate.Irregular heart rateAn arrhythmia is a disorder of the heart rate (pulse) or heart rhythm. The heart can beat too fast (tachycardia), too slow (bradycardia), or irregul...Read Article Now Book Mark Article Tests for MH may include:Blood clotting studies (PT, or prothrombin time; PTT, or partial thromboplastin time) PT, or prothrombin timeProthrombin time (PT) is a blood test that measures the time it takes for the liquid portion (plasma) of your blood to clot. It measures the functio...Read Article Now Book Mark Article PTT, or partial thromboplastin timeProthrombin time (PT) is a blood test that measures the time it takes for the liquid portion (plasma) of your blood to clot. It measures the functio...Read Article Now Book Mark Article Blood chemistry panel, including CK (creatine kinase, which is higher in the blood when muscle is destroyed during a bout of the illness) Genetic testing to look for defects in the genes that are linked with the disease Genetic testingPharmacogenetic testing provides information about your genes and how they control your response to certain medicines. Your genes can affect the des...Read Article Now Book Mark Article Muscle biopsy Muscle biopsyA muscle biopsy is the removal of a small piece of muscle tissue for examination.Read Article Now Book Mark Article Urine myoglobin (testing for muscle protein in the urine) Urine myoglobinThe myoglobin urine test is done to detect the presence of myoglobin in urine. Myoglobin can also be measured with a blood test.Read Article Now Book Mark Article Treatment During an episode of MH, a medicine called dantrolene is often given. Wrapping the person in a cooling blanket can help reduce fever and the risk for serious complications. To preserve kidney function during an episode, the person may receive fluids through a vein. Support Groups These resources can provide more information about MH:Malignant Hyperthermia Association of the United States -- www.mhaus.org National Organization for Rare Disorders -- rarediseases.org/rare-diseases/malignant-hyperthermia US National Library of Medicine - MedlinePlus website -- medlineplus.gov/genetics/condition/malignant-hyperthermia/ Outlook (Prognosis) Repeated or untreated episodes can cause kidney failure. Untreated episodes can be fatal. Possible Complications These serious complications can occur:Amputation Breakdown of muscle tissue Swelling of the hands and feet and problems with blood flow and nerve function (compartment syndrome) Compartment syndromeAcute compartment syndrome is a serious condition that involves increased pressure in a muscle compartment. It can lead to problems with blood flow ...Read Article Now Book Mark Article Death Abnormal blood clotting and bleeding Heart rhythm problems Kidney failure Buildup of acid in the body fluids (metabolic acidosis) Metabolic acidosisMetabolic acidosis is a condition in which there is too much acid in the body fluids.Read Article Now Book Mark Article Fluid buildup in the lungs Fluid buildup in the lungsPulmonary edema is an abnormal buildup of fluid in the lungs. This buildup of fluid leads to shortness of breath.Read Article Now Book Mark Article Weak or deformed muscles (myopathy or muscular dystrophy)Muscular dystrophyMuscular dystrophy (MD) is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.Read Article Now Book Mark Article When to Contact a Medical Professional If you need surgery, tell both your surgeon and anesthesiologist before surgery if:You know that you or a member of your family has had problems with general anesthesia You know you have a family history of MHUsing certain medicines can reduce or prevent the complications of MH during surgery. Prevention Tell your health care provider before having surgery with general anesthesia, if you or anyone in your family has MH. Avoid stimulant medicines and illicit drugs such as cocaine, amphetamine (speed), and ecstasy. They may cause problems similar to MH in people who are prone to this condition.Genetic counseling is recommended for anyone with a family history of myopathy, muscular dystrophy, or MH.Genetic counselingGenetics is the study of heredity, the process of a parent passing certain genes on to their children. A person's appearance, such as height, hair co...Read Article Now Book Mark Article Open ReferencesReferencesAmerican Association of Nurse Anesthesiology. Malignant hyperthermia crisis preparedness and treatment: position statement. 10. issuu.com/aanapublishing/docs/11_-_malignant_hyperthermia_crisis_preparedness_an. Updated April 2018. Accessed May 19, 2025.Yepuri N, Pruekprasert N, Cooney RN. Surgical complications. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 21st ed. St Louis, MO: Elsevier; 2022:chap 12.Zhou J, Zhao J, Yu X, Nozari A, Pessah IN, Allen PD. Neuromuscular disorders and other genetic disorders. In: Gropper MA, Cohen NH, Eriksson LI, Fleisher LA, Johnson-Akeju S, Leslie K, eds. Miller's Anesthesia. 10th ed. Philadelphia, PA: Elsevier; 2025:chap 31.
