$Unique_ID{BRK03962} $Pretitle{} $Title{Malignant Hyperthermia} $Subject{Malignant Hyperthermia Fulminating Hyperpyrexia Hyperthermia of Anesthesia Malignant Fever Malignant Hyperpyrexia MH Pharmacogenic Myopathy Neuroleptic Malignant Syndrome Noonan Syndrome King Syndrome } $Volume{} $Log{} Copyright (C) 1984, 1988, 1989, 1990, 1992 National Organization for Rare Disorders, Inc. 8: Malignant Hyperthermia ** IMPORTANT ** It is possible the main title of the article (Malignant Hyperthermia) is not the name you expected. Please check the SYNONYMS listing on the next page to find alternate names and disorder subdivisions covered by this article. Synonyms Fulminating Hyperpyrexia Hyperthermia of Anesthesia Malignant Fever Malignant Hyperpyrexia MH Pharmacogenic Myopathy Information on the following disease can be found in the Related Disorders section of this report: Neuroleptic Malignant Syndrome Noonan Syndrome King Syndrome General Discussion ** REMINDER ** The Information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Malignant Hyperthermia is hereditary disorder in which a person does not react appropriately to certain drugs due to a genetic abnormality. The patient develops a rapid, high fever after the administration of general anesthesia or certain muscle relaxants. Drugs that could cause this respond include halothane, cyclopropane, or succinylcholine. Symptoms Malignant Hyperthermia occurs in patients who may have been previously unaffected by anesthesia or injection of muscle relaxants, although a few may have reported previous episodes of muscle cramps or weakness following the administration of certain medications. After certain anesthetic drugs or muscle relaxants are administered, the patient quickly develops a very high fever, sometimes as high as 110 degrees. Muscles twitch and become hard, stiff and rigid. Headache, nausea, vomiting, low blood pressure (hypotension), rapid heart beat (tachycardia) and irregular heartbeat (cardiac arrhythmias) may be present. Major life threatening complications include skeleton muscle degeneration (rhabdomyolysis), renal (kidney) failure, accumulation of fluid in the lungs (pulmonary edema) and disruption of blood clotting mechanisms. Levels of creatine phosphokinase are elevated in the patient. Causes People may inherit a predisposition to malignant hypothermia through an autosomal dominant gene. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In dominant disorders a single copy of the disease gene (received from either the mother or the father) will be expressed "dominating" the other normal gene and resulting in the appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is fifty percent for each pregnancy regardless of the sex of the resulting child. Malignant Hyperthermia may also be related to abnormally high levels of calcium in muscle tissue (sarcoplasmic tissue). The gene that regulates the release of calcium from muscles and causes this disorder has been mapped to region q13.1 of chromosome 19. Affected Population Malignant Hyperthermia is extremely rare. Males and females are affected equally. Since most people have no symptoms unless they take certain drugs, the great majority of people with Malignant Hyperthermia are not diagnosed. Anyone with a relative who died during surgery for an unknown reason may want to be tested for Malignant Hyperthermia. Related Disorders Symptoms of the following disorders can be similar to those of Malignant Hyperthermia. Comparisons may be useful for a differential diagnosis: Boys affected with King syndrome (slanted low set eyes, receding chin, webbed neck, spinal abnormalities and short stature) or perhaps Noonan syndrome may experience Malignant hyperthermia and should be monitored closely during procedures requiring anesthesia. (For more information on this disorder, choose "Noonan Syndrome" as your search term in the Rare Disease Database). A similar syndrome may also occur in myotonic disorders, Duchenne muscular dystrophy, branchial hypertonic myopathy, central core disease or in a congenital myopathy with dysmorphic features. It is not yet known exactly what percentage of patients with these muscle disorders are at risk. (For more information on this disorder, choose "Duchenne Muscular Dystrophy" as your search term in the Rare Disease Database). Neuroleptic Malignant Syndrome is a potentially fatal reaction to any of a group of antipsychotic drugs or major tranquilizers (neuroleptics). These drugs are commonly prescribed for the treatment of schizophrenia and other neurological, mental or emotional disorders. Symptoms of Neuroleptic Malignant Syndrome include a very high fever (102 to 104 degrees), irregular pulse, rapid heartbeat (tachycardia), increased rate of respiration (tachypnea), muscle rigidity, altered mental states, high or low blood pressure and profuse perspiration. (For more information on this disorder choose "Neuroleptic Malignant Syndrome" as your search term on the Rare Disease Database). Therapies: Standard Malignant Hyperthermia is best prevented by presurgical detection of those at risk. The most successful test for early detection involves a biopsy of muscle from the thigh. This test is generally reserved for patients from families where a Malignant Hyperthermia episode has occurred, or for patients who have had a suspicious reaction to anesthesia. The test is available at a few test centers in the United States. In those who are susceptible to Malignant Hyperthermia, surgery is often performed under regional or local anesthesia. Malignant Hyperthermia patients should be certain that the drug dantrolene sodium is available at a hospital where they are to undergo surgery. Dantrole sodium is a drug that can stop progress of symptoms if given immediately when the reaction to anaesthesia is identified as Malignant Hyperthermia. Therapies: Investigational Scientists studying Malignant Hyperthermia are attempting to develop a less invasive diagnostic test for this disorder and are also trying to develop more effective therapies for the syndrome. Dr. Ron Gregg and Dr. Kirk Hogan at the University of Wisconsin are trying to develop a test to identify persons at risk for Malignant Hyperthermia. Members of families in which two or more persons have developed Malignant Hyperthermia are needed for the study. Interested parties may contact: Dr. Kirk Hogan University of Wisconsin Dept. of Anesthesiology CSC B6/387 600 Highland Ave. Madison, WI 53792 (608) 262-6042 This disease entry is based upon medical information available through August 1992. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Malignant Hyperthermia please contact: National Organization of Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 847-0407 Malignant Hyperthermia Association of the United States P.O. Box 191 Westport, CT 06881-0191 (203) 847-0407 The North American MH Registry Department of Anesthesia Penn State College of Medicine P.O. Box 850 Hershey, PA 17033 For names of on-call physicians available to treat MH emergencies, call 24 hours a day: Medic Alert Foundation International (209) 634-4917 Ask for: INDEX ZERO, Malignant Hyperthermia Consultant List. For Genetic Information and Genetic Counseling referrals: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 Following is a list of Malignant Hyperthermia clinics: Mayo Clinic Dept. of Anesthesiology 200 1st St., SW Rochester, MN 55905 (507) 285-5601 University of Texas Medical Branch at Galveston Dept. of Anesthesiology Galveston, TX 77550 (409) 761-1906 Hahnemann University Medical School Dept. of Anesthesiology Broad and Vine Streets Philadelphia, PA 19102 (215) 448-7960 Massachusetts General Dept. of Anesthesiology Room ACC3 Fruit Street Boston, MA 02114 (617) 726-8800 University of Toronto MH Investigatory Unit Room 5268 Medical Sciences Building Toronto, Ontario M5S-1A References MENDELIAN INHERITANCE IN MAN, 9th ed.: Victor A. McKusick; Johns Hopkins University Press, 1990. Pp. 499-500. CECIL TEXTBOOK OF MEDICINE, 19th Ed.: James B. Wyngaarden, and Lloyd H. Smith, Jr., Editors; W.B. Saunders., 1990. Pp. 2262-2263. MALIGNANT HYPERTHERMIA. J.L. Moore & E.L. Rice. American Family Physician (May 1992; 45(5)). Pp. 2245-51. MALIGNANT HYPERTHERMIA. R.E. Larew. Postgrad Med (June 1989; 85(8)). Pp. 117-8, 128-9.