Hyperthermia - malignant; Hyperpyrexia - malignant; MH
Malignant 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 drugs: halothane, isoflurane, sevoflurane, desflurane or succinylcholine. MH is a genetic disorder passed down through families.
Hyperthermia means high body temperature. This condition is not the same as hyperthermia from medical emergencies such as heat stroke or infection.
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 of MH include:
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.
Tests for MH may include:
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.
These resources can provide more information about MH:
Repeated or untreated episodes can cause kidney failure. Untreated episodes can be fatal.
These serious complications can occur:
If you need surgery, tell both your surgeon and anesthesiologist before surgery if:
Using certain medicines can prevent the complications of MH during surgery.
Tell your health care provider before having surgery with general anesthesia, if you or anyone in your family has MH.
Avoid stimulant drugs such as cocaine, amphetamine (speed), and ecstasy. These drugs 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.
American Association of Nurse Anesthesiology. Malignant hyperthermia crisis preparedness and treatment: position statement. www.aana.com/docs/default-source/practice-aana-com-web-documents-(all)/professional-practice-manual/malignant-hyperthermia-crisis-preparedness-and-treatment.pdf?sfvrsn=630049b1_10. Updated April 2018. Accessed July 26, 2021.
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. Philadelphia, PA: Elsevier; 2022:chap 12.
Zhou J, Nozari A, Bateman B, Allen PD, Pessah IN. Neuromuscular disorders including malignant hyperthermia and other genetic disorders. In: Gropper MA, ed. Miller's Anesthesia. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 35.BACK TO TOP
Review Date: 4/24/2021
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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