Everything you need to know about trigger point injections
Muscle pain can develop for a variety of reasons, from sleeping in the wrong position to tearing large muscle groups during an intense weightlifting session.
Although many types of muscle pain resolve after a few days of rest, people who have persistent or chronic muscle pain may require medical treatment.
Chronic muscle pain can have a significant impact on a person's ability to function and their quality of life. Trigger point injections may offer immediate benefits to people who have chronic muscle pain.
Below, learn about the uses, efficacy, side effects, and risks of trigger point injections.
What are trigger point injections?
A trigger point injection may help treat an issue that affects the musculoskeletal system.
Trigger point injections may treat chronic muscle pain related to myofascial trigger points, which are highly sensitive bundles of fibers in tight bands of muscle.
The treatment involves injecting medication directly into myofascial trigger points. The doctor will determine the best type of medicine based on the severity and underlying cause of the pain.
Trigger point injections can include:
- a local anesthetic, such as lidocaine, which blocks pain receptors in muscles
- a corticosteroid, which reduces inflammation in the muscle and connective tissue surrounding a nerve
- botulinum toxin A (Botox), which interferes with nerve signaling pathways and prevents muscle contractions
During the procedure, the doctor will insert a small needle into a myofascial trigger point and inject the medication.
People who have especially tense muscles may feel a crunching sensation when the doctor inserts the needle. This feeling usually subsides as the muscle relaxes.
Trigger point injections may help relieve pain caused by conditions that affect the musculoskeletal and nervous systems, such as those below.
Myofascial pain syndrome
Trigger point injections may help relieve symptoms of myofascial pain syndrome, a chronic pain condition that affects the muscles and their surrounding tissue.
In myofascial pain syndrome, trigger points stimulate pain responses in seemingly unrelated parts of the body. This phenomenon is called referred pain.
Trigger point injections can reduce localized muscle pain by relaxing the affected muscles, and researchers believe that the injections interrupt the nerve signaling pathways that cause referred pain.
Possible causes of myofascial trigger points include:
- injury or trauma to a muscle
- repetitive motions
- poor posture
- psychological stress
In addition to referred pain, a person with myofascial pain may experience:
- pain in specific parts of a muscle
- pain that intensifies when the person moves or stretches the affected muscle
- muscle knots that the person can feel by touch
- muscle stiffness or weakness
- a limited range of motion
The exact cause of fibromyalgia remains unknown, but possible risk factors include:
- a history of autoimmune disorder, such as lupus or rheumatoid arthritis
- physical or psychological trauma
- a family history of fibromyalgia
- being female
Symptoms of fibromyalgia include:
- pain and stiffness throughout the body
- numbness or tingling in the hands and feet
- digestive problems
- poor sleep and daytime fatigue
- difficulty concentrating
- symptoms of depression or anxiety
Historically, doctors diagnosed fibromyalgia in people who reported pain or tenderness in specific trigger points throughout the body.
Unlike myofascial pain syndrome, which causes localized muscle pain, fibromyalgia causes widespread, or systemic, pain.
This suggests that fibromyalgia pain comes from neurological problems that affect how the brain processes sensory information.
With that said, myofascial trigger points and fibromyalgia cause similar pain profiles, and some researchers believe that myofascial trigger points contribute to fibromyalgia pain.
The researchers found a significantly higher number of myofascial trigger points in the group with migraine.
The authors of one 2016 study examined the relationship between myofascial trigger points and pressure pain sensitivity in people with episodic or chronic tension-type headaches.
The individuals with more myofascial trigger points were more sensitive to pressure pain than those with fewer points. The findings suggest that myofascial trigger points influence the intensity of these types of headache.
Do they work?
Trigger point injections may offer immediate pain relief and improved range of motion for people with chronic muscle pain.
However, these injections do not affect everyone in the same way. Some people experience significant pain relief immediately after the injections, while others find that several days or weeks can pass before their pain improves.
Some people do not benefit at all from trigger point injections.
Researchers behind a small 2019 study investigated the effects of these injections in people with abdominal muscle pain. The participants reported significant reductions in pain 2 years after the initial injection. Five participants had required an additional injection, while another had experienced no response to the treatment.
Trigger point injections can cause various immediate and long-term side effects, including:
- pain or temporary numbness around the injection site
- discoloration or dimpling of the skin near the injection site
- lightheadedness or dizziness
Also, anesthetic-based trigger point injections can cause a severe form of muscle damage called myonecrosis. This may heal within 3–4 weeks.
Pain, swelling, and tenderness near the injection site usually wear off after a few hours. If any side effect does not resolve within a couple of weeks, contact the doctor.
While trigger point injections rarely cause serious complications, they can lead to:
- infection at the injection site
- muscle or nerve damage
- rarely, air or gas accumulating in the space between the chest wall and the lungs, which may cause one or both lungs to collapse
Ultrasound imaging can help minimize the risk of developing a serious complication of trigger point injections.
Trigger point injections can be a safe treatment for chronic pain conditions, such as myofascial pain syndrome, fibromyalgia, and tension-type headaches.
A doctor or another healthcare provider administers the injections directly into the affected muscle.
The injection may contain a local anesthetic, a corticosteroid, or botulinum toxin A.
Trigger point injections can provide immediate pain relief for some people, while others may have no response to the treatment.
A doctor can provide more detailed information about the risks and benefits of this treatment.