What is botulinum toxin?
Botulinum toxin is the purified extract of a poison from bacteria. When injected, it blocks the messages sent from the brain to the muscles, telling them to contract. When muscles stay contracted they become painful. By blocking these signals, botulinum toxin makes the muscles relax. Over several months this blocking effect wears off, allowing the muscles to contract again. By this time, it is hoped that the muscle will contract normally and not go into spasm or cramp.
What has gone wrong?
It is not always clear why these trigger points develop. They can be associated with various illnesses, including myofascial (my-oh-fay-shul) pain and chronic fatigue states. Sometimes a muscle can be in spasm after a stroke. Some headaches, including migraines, can be related to muscle spasm. These illnesses can be treated with botulinum toxin injections.
The pain may be related to an underlying inflammation. Often it is due to the lack of use of a muscle, when pain of whatever cause has been present for a long time.
The aim of the procedure is to reduce the spasm and ‘unknot’ the muscle. This reduces the sensitivity of the trigger point and therefore fewer pain messages are sent. It is hoped this will produce long lasting relief.
Many patients benefit from a botulinum toxin injection, reducing their pain. However, there is a chance that the pain will not improve, will change or will get worse. Some patients will need to have a further botulinum toxin injection. The muscle relaxing effect will continue to work for about 3-6 months. Those patients who get little or no benefit may want to consider other treatments.
Your pain should be reduced and you should be able to move around more easily. You will be able to perform your daily activities more easily. You will be able to reduce the number of painkilling tablets that you take.
Are there any alternatives?
By the time that you have the botulinum toxin injection you should have already tried other, more simple treatments. These include rest, painkilling and anti-inflammatory tablets, and physiotherapy.
You may also have tried a transcutaneous electrical nerve stimulation (TENS) machine for your pain. This works by sending soothing pulses across the surface of your skin and along the nerve fibres. These pulses prevent pain signals reaching your brain. They also stimulate your body to produce higher levels of its own natural painkillers (endorphins).
What if you do nothing?
If you do nothing there are several things that may happen:
Who should have it done?
The following groups of patients should have the procedure done:
Patients with easily identified, painful trigger points
Patients with permanently contracted painful muscles
Patients with some forms of headache, where muscle spasm is involved
Patients with muscle spasm of cerebral palsy
Patients with muscle spasm from a stroke
Patients with spasticity from a birth injury or multiple sclerosis
This list lengthens as the technique is successfully tested on more conditions. Your doctor will be able to advise you.
Who should not have it done?
Each patient must make the final decision as to whether to proceed or not. If you are unhappy about the procedure for any reason, you should not continue.
There are specific medical situations when a botulinum toxin injection should not be done and they are as follows:
When a patient is on medication (drugs) that prevent blood from clotting, such as warfarin. This would lead to more bleeding than normal. It may be possible to stop the medication a few days before the procedure. This will need to be discussed with your doctor
When a patient is suffering from an illness that prevents blood from clotting, such as haemophilia. This would also lead to more bleeding than normal
When there is infection of the skin over the site where the needle needs to be put in
When a patient has an allergy to botulinum toxin
When a patient has unstable bony structures under the muscles to be injected
Author: Dr Sean White FRCA. Consultant in pain and anaesthesia
© Dumas Ltd 2006