What is MH?
The science and practice of Medicine have undergone a tremendous evolution and lives are saved daily. But despite this, we see unexpected, sudden deaths in healthy individuals undergoing minor surgery. This tragedy happens to patients susceptible to Malignant Hyperthermia. MH is a inherited syndrome of skeletal muscle which is undetected until exposed to certain anaesthetic agents. This then triggers a rapid cascade of cellular events that cause a very high temperature, uncontrolled muscle contraction, cell rupture that leads to multi-organ failure and death.
Is it dangerous?
Yes it is a killer. It is the most common cause of death in healthy people receiving general anaesthesia. Even when treated, MH can still cause death, or survivors may end up with brain damage or functional impairment of their muscles, kidneys, heart or lungs.
Which anaesthetics are unsafe?
Succinylcholine which is a depolirazing muscle relaxant and all volatile inhalation anaesthetics namely:
Which anaesthetics are safe?
All other general anaesthetic agents and all local anaesthetics are safe.
Who should know about it?
You should inform your surgeon and anaesthetist the day before your surgery, as certain specific preperations should be done to make sure you receive a trigger-free safe anaesthetic. MHS patients must always be first on the theatre list with a well-flushed and prepared anaesthetic machine.
What about the dentist?
All local anaesthetics, sedatives and even laughing gas are safe. If the dentist book you for theatre for removal or dental repair you must inform anaesthetist and make sure you are first on the list.
Why should I get tested?
“Test a muscle, save a family”. If you have a diagnosis of MHS death or near-death can be prevented in you and your family. If you know it’s there you can prevent the triggers.
Can it be treated?
Prompt recognition of an unanticipated suspected MH crisis is vital towards a favorable outcome. Getting help and the MH crash cart and immediately implementing the MH action plan can save a life. If an acute episode get recognized too late even giving dantolene can not save the patient.
Can it trigger outside theatre?
Yes. MH can trigger in the recovery room, emergency department, dentists chair and in the intensive care unit if any unsafe agent has been administered. Several cases of “awake MH” have been described where exercising in hot conditions lead to heat stroke where the genetic changes in MHS patients were present. It is still unknown what is the exact relationship between exercise induced rhabdomyolysis, heat stroke and MH. The formal recommendation to MHS patients is to live normal lives except when going to theatre. Although caution must be taken not to participate in extreme sports in very hot climates.
Can it be associated with other disorders?
Patients suffering from King-Denborough syndrome, Central core disease or Multi-mini core disease have a proven definitive MH risk. They should never be exposed to any MH triggers. Other myopathies where MH triggers should be avoided in order to prevent an MH-like event is Duchennes and Becker muscular dystrophy.
Can my child have it?
MH is an autosomal dominant inherited condition. Meaning that every sibling has a 50% chance of having inherited the MHS mutation. This is why it is very important to get tested and to get your family tested because this is not a disease of an individual but it affects a whole family.
Why wear a medic-alert?
In the unfortunate event that you are involved in a traumatic accident or you are comatose for whatever reason and unable to provide a medical history, a medic-alert could save your life. If you need emergency surgery and the health care providers involved do not know that you are MHS, fatal MH triggers may be administered.Medic-alerts are also very important in suspected or known MHS children for safety reasons.