Malignant hyperthermia

Malignant hyperthermia (MH) is an inherited predisposition. People who are predisposed to MH sensitivity react to certain anesthetic drugs with a massively increased metabolism. The triggering drugs are inhaled anesthetics and the muscle relaxant drug succinylcholine. If such a condition is not recognized quickly and treated correctly, it can lead to death. This is where the name "malignant hyperthermia" comes from. "Malignant" means "malignant" because the MH episode can lead to death, although this is relatively rare today. "Hyperthermia" is the "rise in temperature" or fever, which can reach temperatures of over 42 degrees.

The predisposition to MH lies in the muscles. On contact with the triggering medication, the entire musculature is activated uncontrollably. This leads to an extreme increase in metabolism. This leads to a very strong increase in oxygen consumption and at the same time heat is produced by activating the muscles.

The Swiss MH Diagnostic Center at the University Hospital Basel also holds all the results of tests carried out and the associated family information. Many additional genetic tests have been carried out in recent years and these results are also stored at the MH Diagnostic Center.

Molecular genetic tests are also offered or organized by the Swiss MH Diagnostic Center Basel. This ensures that people who undergo tests in Basel benefit from the stored data and can count on optimal professional treatment and information. Because the MH-Diagnostik Zentrum Basel maintains contacts with other MH-Diagnostik centers worldwide, appointments for examinations in other countries can also be arranged there. The results obtained there can be incorporated into the family trees of our database and thus benefit the whole family.

The standard test for MH is the open muscle biopsy and the in-vitro contracture test. Approximately three grams of tissue are taken from the thigh muscles and tested at the MH Diagnostic Center. This Europe-wide standardized test is complex and is only offered in Switzerland at the MH Diagnostic Center in Basel. As the removed muscle must be examined immediately in a special nutrient solution at the MH Diagnostic Center, the muscle can only be removed at the test site. The operation to remove the muscle must therefore take place in Basel.

Since 2001, MH diagnostics can also be carried out using molecular genetic methods in certain cases. The genetic basis of MH is extremely complex and therefore genetic testing only makes sense for people with a known MH-causing gene mutation in the family. If this mutation cannot be detected, the possibility of MH susceptibility cannot be ruled out. In the absence of the MH mutation, a muscle biopsy must be carried out in Basel.

Anyone who has experienced a suspected MH anesthetic incident should be tested for malignant hyperthermia. Relatives of MH-susceptible persons should also be tested - depending on the degree of relationship.

You do not have to travel to Basel for the genetic test. You can also have the blood sample taken by your family doctor and send it to us by A Mail.
It is important that you contact us before you have a blood sample taken. The genetic test is not always possible.

The muscle contracture test must be carried out at the University Hospital Basel. This is the only MH center in Switzerland. As the muscle must still be able to move during the examination in the laboratory, not too much time must elapse between the removal and the laboratory test.

The MH ID cards are only issued to people who have been tested as MH-sensitive. An exception is made for children who cannot yet be tested and for pregnant women. Cards can be ordered here.

For the muscle biopsy, you will need to come to Basel for an outpatient operation. In the in-vitro contracture test, small pieces of muscle are examined in the laboratory. The muscle pieces are suspended in small strips in a test bath and stimulated with an electric current. The current stimulates the muscle so that it twitches every two seconds. This twitching serves as a check that the muscle is still responsive.

A drug is then added to the test bath and the muscle's reaction to it is checked. We need halothane (an anesthetic drug) and caffeine as test drugs. Both drugs cause the muscles of MH-sensitive people to contract. If the muscle contracts at a certain concentration of halothane and/or caffeine of 0.2 grams or more, the test is considered positive, i.e. MH sensitivity is present.

This test is very time-consuming and takes two people several hours to complete. The test must be carried out immediately after the muscle has been removed so that the muscle is still able to contract. For this reason, the muscle extraction must take place in Basel.

Incidentally, the caffeine used for the test is in a concentration that is not reached when drinking coffee (espresso, ristretto, etc.). MH-sensitive people can therefore drink coffee without any problems.

It isimportant to mention that you must provide us with current diagnoses and current medication when registering for the diagnostics. It is also important that no other surgical procedure has been carried out in the 3 months prior to the test (with the exception of minor skin procedures)

Genetic testing is advantageous because you do not have to travel to Basel to have blood taken (although you can do this during the pharmacogenetic consultation). The second advantage is that no operation is necessary for the muscle biopsy. This also means that there is no post-operative discomfort and no loss of working hours.

However, genetic testing also has disadvantages: genetic testing is generally only useful if a genetic change (mutation) causing MH has already been found in your family.It is therefore important to know that a negative genetic test requires a muscle biopsy and an in-vitro contracture test to rule out or confirm MH susceptibility. If you register for MH testing, we will always clarify whether you are eligible for genetic testing or whether a muscle biopsy is necessary