A Comparison of Fibromyalgia & Myofascial Pain Syndrome

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Back pain

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The muscle pain present in both fibromyalgia (FM) and myofascial pain syndrome (MPS) is why these two conditions are sometimes mistaken for one another or erroneously lumped together as one condition. While FM and MPS do resemble each other, they can be easily distinguished through a careful medical history and physical exam—and a correct diagnosis is a key to moving forward with an effective treatment plan.

Comparing these disorders from start (what causes them) to finish (how they are treated) can help you navigate a potential misdiagnosis or dual diagnosis.

Causes

The pathogenesis of FM and MPS, or why these conditions develop in some people, remains unclear. Scientists, however, have explored many plausible theories.

One potential shared cause of FM and MPS involves a phenomenon called central sensitization. With central sensitization, a person's brain remains on high alert, perceiving normal sensations as "painful" or mildly painful stimuli as severely painful.

Besides altered pain processing in the nervous system, genetic and environmental triggers like sleep disturbances or stress may contribute to the development of FM or MPS. For MPS specifically, a muscle injury from engaging in strenuous repetitive activities or some other sort of trauma is a common trigger.

Lastly, hormonal changes may play a role, especially for FM, which is significantly more common in females than males.

Symptoms

Some symptoms associated with MPS are similar to the symptoms of FM, while others are linked to only one of these diagnoses.

Similarities

Symptoms common to both MPS and fibromyalgia include:

Differences

Perhaps the greatest symptom difference between MPS and FM is the location of the pain. While muscle tenderness is the paramount symptom of both conditions, the pain seen in MPS is regional (e.g., localized to one anatomic area, like the right neck or shoulder) whereas the pain in FM is widespread or "all over."

Another symptom difference between FM and MPS is that a person with MPS may only have pain for a short period of time, whereas the pain in FM is generally always chronic.

Lastly, it's important to note that besides muscle pain, the other symptoms mentioned above (e.g., fatigue or numbness and tingling sensations) are overall reported more frequently in people with FM than MPS.

Diagnosis

While the diagnosis of FM or MPS both requires a detailed clinical exam by either a primary care doctor, rheumatologist, or pain specialist, a key diagnostic difference lies in the identification of trigger points in MPS and tender points in FM.

Trigger Points in MPS

Myofascial pain syndrome is diagnosed by the presence of trigger points—small, hard knots that you can sometimes feel under your skin. A trigger point represents a taut band of muscle. The knot itself is not generally painful when poked, but it causes pain in another area of the body (known as referred pain).

Trigger points typically form after the tissue is injured and, for some reason, don't heal properly. Experts don't know why damage that heals normally in most people causes trigger points in others. However, studies suggest that muscle injury in some people leads to abnormalities where the nerve cells connect to muscle cells.

While trigger points are usually found by an experienced doctor simply by touch (palpation), other tests such as magnetic resonance elastography (MRE) or tissue biopsy may be ordered. That said, the role of imaging in diagnosing MPS has not been fully teased out.

Tender Points in Fibromyalgia

FM is diagnosed primarily on a person's report of widespread pain, along with a finding of multiple tender points on a physical exam.

The tender points of FM are different from the trigger points of MPS in that they represent exquisitely tender areas of muscles that hurt with simple manual pressure. In addition, the tender points of FM do not refer pain like the trigger points of MPS do.

Besides a history and physical exam, if your doctor is considering a diagnosis of FM (or MPS, for that matter), he or she may order blood tests to rule out other medical conditions. For example, an erythrocyte sedimentation rate (ESR) may be ordered to rule out an underlying inflammatory process. Likewise, a thyroid-stimulating hormone (TSH) test may be ordered to rule out thyroid disease. Both test results should be normal in FM.

As with MPS, there is no imaging test or scan to make or confirm a diagnosis of FM. Depending on a person's symptoms, though, a doctor may recommend further studies (for example, a sleep study since sleep problems are common in FM).

Treatment

As with symptoms and diagnosis, there is some overlap in the treatment of MPS, but also important differences.

MPS Therapies

The primary treatment of MPS is a trigger-point injection, sometimes called dry needling. With a trigger point injection, a doctor inserts a needle directly into the trigger point or into several places around the trigger point to loosen up the taut muscle bands. The doctor may also inject a pain-relieving medication, such as lidocaine.

Besides trigger point injection, other potential MPS therapies include:

Acupuncture

Acupuncture is an ancient Chinese practice similar to dry needling. While studies of its use in MPS are limited, they are promising, and many patients and practitioners report good results.

Physical Therapy

A special kind of therapy called spray-and-stretch is common for treating MPS. A physical therapist guides you through stretching exercises while spraying a numbing substance on your muscle. The therapist may also use certain massage techniques to loosen your muscles and trigger points. In addition, a therapist can work with you on factors such as poor posture that may contribute to MPS.

Oral Medications

Common drugs for MPS include nonsteroidal anti-inflammatory drugs (NSAIDs), such as Aleve (naproxen) and Advil (ibuprofen). Tricyclic antidepressants, such as Elavil (amitriptyline) or the serotonin-norepinephrine reuptake inhibitor Cymbalta (duloxetine), are sometimes prescribed for the treatment of MPS.

Topical Medications

Topical capsaicin or lidocaine applied to the skin over the trigger point may also be used to treat MPS.

FM Therapies

A multidisciplinary approach is recommended for the treatment of FM, including both pharmacological and non-pharmacological strategies.

Medications

Research show trigger-point injections are not effective at relieving fibromyalgia tender points, and NSAIDs are not effective at treating FM pain.

However, similar to MPS, antidepressants like Elavil (amitriptyline) or Cymbalta (duloxetine) may be prescribed. The anticonvulsant Lyrica (pregabalin) may also be considered in the treatment of fibromyalgia.

Non-Pharmacological Strategies

Similar to MPS, physical therapy (albeit in different forms) and acupuncture may be incorporated into the treatment plan for someone with FM.

More specifically, for FM, following an exercise routine (e.g., biking, running, or swimming) has been found to reduce muscle pain. Tai chi, yoga, hypnosis, cognitive-behavioral therapy, and biofeedback may also provide benefit for those with FM.

A Word From Verywell

While fibromyalgia and myofascial pain syndrome resemble each other in certain aspects, they are definitely not the same condition. The upside is that once you have a clear diagnosis, you and your doctor can take the next step in devising a treatment plan that gives you pain relief.

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