Guest Author - Wollie Woehler

Malignant hyperthermia is an inherited disease that causes a rapid rise in body temperature (fever) and severe muscle contractions when the affected person receives general anesthesia. It is also known as Hyperthermia - malignant; Hyperpyrexia – malignant.

A friend of ours died unexpectedly during heart surgery. The operation went well until he suddenly developed a very high fever. It was a shock for the family, friends and community as he was only in his 40s. What happened?

A Malignant Hyperthermia crisis is the result of biochemical chain reaction response “triggered” by commonly used general anesthetics and the paralyzing agent succinylcholine within the skeletal muscles of susceptible patients.

General signs of a Malignant Hyperthermia (MH) crisis include tachycardia (a rise in heart rate), a greatly increased body metabolism, muscle rigidity and/or fever that may exceed 110 degrees F.

Other severe complications may include cardiac arrest, brain damage, internal bleeding or failure of other body systems. The patient may also die as result of secondary cardiovascular collapse.

Over 80 genetic defects have been associated with MH. It is inherited with an autosomal dominant inheritance pattern. This means that a parent with MH susceptibility usually have a 50% chance of passing the gene defect to his/her children.
Persons who are carriers for susceptibility may be completely unaware of this risk unless they, or a family member, developed a life-threatening crisis during anesthesia.
It is important to know that not everyone who has a gene defect linked to MH develops the MH crisis upon each exposure to triggering anesthetics. The importance of talking to the physician before any surgery is done; informing him about your MH susceptibility is of the utmost importance, enabling him to take the necessary preoperative precautions. Neuromuscular patients should always insist on physicians and anesthesiologists taking the risk of a MH crisis into consideration when performing surgery.

Successful treatment for MH can only be performed if The MH crisis is being identified and treated early in its course. The treatment must be swift, focused and continued for many hours after an episode begins. Since 1979, the drug androgene sodium for injection (Dentium® I.V.) has been available for the treatment of an MH crisis and has contributed greatly to a dramatic decline in deaths and/or resultant disabilities associated with such occurrences.

Tests such as a simple diagnostic blood test are not currently available.
Since not all of the genes responsible for MH have been identified, the genetic tests are only useful in families with a suspicious history of MH. Even if the genetic tests do not show that you have one of the genes for MH, you may still have other unidentified genes and therefore may be at risk for MH.

The “gold standard” test, most accurate test in use for the last 30 years, involves a biopsy of skeletal muscle from the thigh. It is usually reserved for those with a family history of MH or when a patient has had a previous suspicious reaction to anesthesia.

Surgery can be safely performed in the known MH-susceptible patient. However, no triggering anesthetics must be used as well as special precautions and techniques, including close monitoring of appropriate vital functions. Close monitoring occurs in all anesthetics. In surgery for a known MH-susceptible patient, the anesthesiologist should:

- Avoid the use of MH-triggering anesthetics.
- Be familiar with the signs and treatment of MH.
- Continuously monitor the patient's expired carbon dioxide concentration.
- Continuously monitor the patient's temperature (also during recovery), as skin temperature is not reliable in this situation.

Research is continuing, as there is still much to learn regarding malignant hyperthermia. Awareness about MH is far from satisfactory and special efforts
should be made to inform the ignorant majority of the general public.

Click below and scroll down about five screens for a recommended book on Malignant Hyperthermia:

Malignant-Hyperthermia-Membrane-Membrane-Linked-Diseases

Do you need a Medical Dictionary to familiarize yourself with all the medical terminology? Click below and scroll down about five screens:

Merriam-webster's Medical Dictionary

Or

Taber's Cyclopedic Medical Dictionary (INDEXED) & Taber's Electronic Medical