Malignant hyperthermia (MH) is severe, potentially
fatal increased body energy consumption after exposure to certain anesthetic
drugs. Malignant hyperthermia occurs in persons who have a genetic (inherited) susceptibility to this medical problem. Family
history of death during general anesthesia (being
put to sleep for surgery) or having a high body temperature during or after
general anesthesia are the most likely indicators that a person may be susceptible
to MH. The June 15, 2005, issue of JAMA includes
an article about genetic testing (DNA testing from
a sample of blood or other tissue) that can detect the presence of susceptibility
for MH in persons with a family history of the disorder.
It is crucial for persons who are known to have MH or who have family
members with MH to inform their doctors about it, particularly if they are
having any type of anesthesia or surgery. Wearing a medical alert bracelet
is a helpful way to communicate this in case of an emergency, especially for
children. Anesthesiologists (doctors with special
training in pain control and other medical care during surgery) can prevent
the triggering of MH if they know in advance of an individual's susceptibility
to MH. Anesthesiologists avoid certain commonly used medications for persons
with MH. These include succinylcholine (a muscle
relaxant used during general anesthesia) and the volatile (inhaled) anesthetic agents. When the anesthesiologist knows in advance
about a person's own or family history of MH, general or regional (such as spinal, epidural, or nerve block) anesthesia can
be safely administered. For patients or professionals who have questions about
MH, the Malignant Hyperthermia Association of the United States provides a
24-hour hotline: 800/644-9737.
If an MH crisis is suspected in the operating room, all triggering anesthetic
agents are stopped. Dantrolene, a medication to treat
MH, is given intravenously with close monitoring of breathing, heart function,
and body temperature. Oxygen is provided with an increased breathing rate
using a mechanical ventilator to remove excess carbon dioxide from the individual's
system. Cooling techniques including cooling blankets and ice packs may be
required if the patient's temperature becomes markedly elevated. Medications
to control blood pressure or treat abnormal heart rhythms may also be needed.
American Society of Anesthesiologists 847/825-5586 http://www.asahq.org
Malignant Hyperthermia Association of the United States 24-hour
hotline: 800/644-9737 http://www.mhaus.org
To find this and previous JAMA Patient Pages, go to the Patient Page
link on JAMA's Web site at http://www.jama.com. Many are available in English and Spanish.
Sources: American Society of Anesthesiologists, Malignant Hyperthermia
Association of the United States
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TOPIC: GENETIC DISORDERS
Torpy JM, Lynm C, Glass RM. Malignant Hyperthermia. JAMA. 2005;293(23):2958. doi:10.1001/jama.293.23.2958