Myofascial Pain Syndrome and Fibromyalgia: Similar Symptoms, Distinct Diseases

The Centers for Disease Control and Prevention estimates that about 2% of the population is affected by fibromyalgia (FM). The toll of FM on patients includes an average of 17 missed workdays per year (compared with 6 days for people without FM), hospitalizations about every 3 years, and a greater likelihood of not being able to continue working after hospitalization. Estimated costs of FM are about $6000 per person per year.¹

FM and myofascial pain syndrome (MPS) appear on the surface to be very similar, or even the same problem.² Both have widespread muscle pain and tightness,³ produce an increased response to painful stimuli, and are frequently accompanied by other painful conditions, such as headaches, arthritis, degenerative disc disease, and chronic fatigue.⁴ Billing coding for FM is even lumped with “myositis and myalgia, unspecified.”¹ The overlap of symptoms leads some individuals to question whether MPS is a subset of FM. However, the 2 are distinct syndromes requiring different treatments (Table^3,4).^1,3

What Is Fibromyalgia?

FM is a generalized soft tissue pain syndrome caused by limbic and/or neuroendocrine dysfunction.^2,4 The primary symptoms of FM are widespread pain, fatigue, insomnia, impaired thought processes, altered sensation, poor physical function (including poor balance), oral and ocular problems, headaches, sexual dysfunction, and psychological effects.⁴ FM affects daily functioning, quality of life, and relationships.⁴ It occurs twice as often in women as in men, has a strong genetic component,⁴ appears most often in middle age, and has a greater incidence of occurrence with increasing age.¹

The presence of tender points and widespread, nonfocal, soft tissue pain are the hallmarks of FM.² The American College of Rheumatology diagnostic criteria call for 11 tender points and widespread pain, and most patients have multiple symptoms.⁴ FM tender points are not trigger points; they occur across the entire body and do not have jump signs (patient vocalizing or withdrawing from palpation) or referred pain.^3,4 Augmented pain and sensory processing occur; patients with FM sense pain more intensely, and stimuli such as sounds, smells, and heat are found noxious at low levels.⁴ FM pain is unrelated to, or out of proportion with, any physical damage or inflammation.⁴ Imaging studies show hyperactivity in a number of regions of the brain.⁴ FM patients have low norepinephrine and increased opioid receptors and substance P.⁴ Once elevated, substance P levels do not noticeably change, even in response to painful stimuli.⁴

Nonsteroidal anti-inflammatory drugs (NSAIDs) and opiates are not very effective for patients with FM³ and may even cause hyperalgesia; however, substances that raise both serotonin and norepinephrine (tricyclics, duloxetine, milnacipran, and tramadol) levels work, and gabapentin and pramipexole may also help.⁴ Exercise and yoga are beneficial,⁴ and cognitive behavioral therapy and relaxation techniques help some.⁴ Multimodal therapy, which combines psychological therapy, medication, and exercise, is recommended.^2,4 The combination of strength training, aerobic and flexibility exercise, and an FM self-help course have shown the most improvement of any treatment combinations looked at.⁴

What Is Myofascial Pain Syndrome?

MPS is a localized soft tissue pain syndrome with local pain, referred pain, and trigger points.⁴ MPS trigger points are localized, highly painful areas that lead to a jump sign,⁵ and the taut, rope-like bands of muscle have a characteristic nodular texture.^2-5 MPS trigger points can be active (causing the jump sign), latent (a node on the taut muscle, not painful), secondary (becomes painful from overactivity of a different muscle), or as a satellite (becomes active because of a nearby trigger point).³

It is theorized that MPS is caused by biological factors interacting with nerve pain, along with psychological factors.^2,4 Suspected MPS causes include trauma to muscles or intervertebral discs, inflammatory conditions, myocardial ischemia, overexercising or underexercising, poor posture, fatigue, sleep loss, stress, hormonal changes, poor nutrition, intense cooling of the body (such as from sleeping in front of an air conditioner), obesity, and tobacco use.³

Trigger points appear after trauma, overuse, or prolonged muscle spasms² and may not be present in every muscle group.⁵ Excessive acetylcholine is seen and may lead to sustained muscle contraction; cortisol, epinephrine, and norepinephrine concentrations are also elevated.⁴ Abnormal electrical activity at trigger points may also be related to excessive acetylcholine.⁴ This leads to the twitch or jump response in which a brisk and painful muscle reaction is seen.⁴

MPS can affect the trunk, extremities, and face.⁴ Although it is distinct from FM, there are no clear diagnostic criteria.⁴ An MPS diagnosis includes confirmation of these symptoms: palpable taut muscle bands, tenderness of a nodule on the taut bands, and painful or limited stretching of the area.³ Other diagnostic criteria include observation of a twitch response, altered pain or sensation on nodules on the taut bands, spontaneous electromyographic activity, increased proinflammatory cytokines (IL-8 and TNF-alpha), and low cortisol levels.³ Palpation, observation, and patient awareness of pain referral are used to diagnosis MPS in patients.⁵ Giving a diagnosis usually includes locating the trigger points and seeing referred pain (especially corresponding to referral maps).⁴

The most effective MPS treatments are multimodal, including pharmacologic treatment, physical therapy, and ergonomics, and treat the underlying pain generators. Treatments are also most effective when implemented early on.^3,4 Therapy options include injection of promethazine or anesthetics; manual therapy (compression, stretching), including alternating the use of heat and stretching with vapocoolant; topical analgesics; use of glucosamine or other supplements; NSAIDs; or botox.^2-4 Pain and fatigue are common causes of physician visits, and nearly one-third of such patients have FM. FM and MPS share neurobiological causes, as well as physical and mental symptoms. Nonpharmacologic treatment for both syndromes includes improving posture, bracing devices, massage therapy, chiropractic care, yoga, heat and cold therapy, and electrical stimulation.³ Accurate diagnosis is particularly important for determining appropriate pharmacologic treatment and improving patients’ quality of life.

Debra Freiheit has been a practicing pharmacist and human services professional for over 25 years. Specializing in medical information, she has compiled a broad spectrum of experience obtained through research for companies including Cerner and PPD Inc. With an emphasis on clear and concise information transfer, Debra has built a career communicating data with medical professionals and patients. Education and knowledge have been the motivation of a rich career of caregiving through research. Debra’s current project involves the creation of a multinational database of drug information.

References

• Arthritis basics: fibromyalgia. Centers for Disease Control and Prevention website. www.cdc.gov/arthritis/basics/fibromyalgia.htm. Published November 7, 2012. Updated January 12, 2015. Accessed April 9, 2015.
• Schneider MJ. Tender points/fibromyalgia vs. trigger points/myofascial pain syndrome: a need for clarity in terminology and differential diagnosis. J Manipulative Physiol Ther. 1995;18(6):398-406.
• Chandola HC, Chakraborty A. Fibromyalgia and myofascial pain syndrome-a dilemma. Indian J Anaesth. 2009;53(5):575-581.
• Crooks MT, Hsu ES, Ferrante FM. Essentials of Pain Medicine. 3rd ed. Philadelphia, PA: Eselvier Inc; 2011.
• Myburgh C, Holsgaard Larsen A, Hartvigsen J. A systematic, critical review of manual palpation for identifying myofascial trigger points: evidence and clinical significance. Arch Phys Med Rehabil. 2008;89(6):1169-1176. doi: 10.1016/j.apmr.2007.12.033.