“Trigger points” are small areas within muscles that are tender and when they are pressed they cause pain to spread through the muscle. Most patients will have pain from several trigger points.
Injections are often made into several trigger points in the investigation and treatment of pain.
The injection will confirm that the pain is coming from the trigger points, and will help to treat it. Without other treatment, the pain will sometimes return.
Local anaesthetic in the injection wili reduce the pain within a few minutes, and will work for several hours. There may be some weakness, a feeling of heaviness and sometimes a feeling of numbness that usually lasts for a few hours at most.
A steroid is often included in the injection to prolong the effects: the steroid is chosen to remain in the trigger point, and has little effect on the rest of the body. It takes more than a day to have an effect, and the pain may return as the local anaesthetic wears off before the steroid begins to work.
Because of the effects of the injection, you should not travel home alone, and someone should stay with you on the day of the injection. The strength and sensation around the nerve should be normal by the next day.
A few people feel faint for a short time after their injection. If this happens you wili be asked to lie down, and may be given medication through a needle inserted into a vein.
You cannot have an injection if you are allergic to local anaesthetics. We put a dressing over the injection, and you should tell us if you are allergic to plasters, tapes or dressings.