In fibromyalgia, any fibromuscular tissues may be involved, especially those of the occiput, neck, shoulders, thorax, low back, and thighs. There is no specific histologic abnormality. Symptoms and signs of fibromyalgia are generalized, in contrast to localized soft-tissue pain and tenderness (myofascial pain syndrome), which is often related to overuse or microtrauma.
Fibromyalgia is common; it is about 7 times more common among women, usually young or middle-aged women, but can occur in men, children, and adolescents. Because of the sex difference, it is sometimes overlooked in men. It often occurs in patients with other concomitant, unrelated systemic rheumatic disorders, thus complicating diagnosis and management.
Current evidence suggests fibromyalgia may be a centrally mediated disorder of pain sensitivity. The cause is unknown, but disruption of stage 4 sleep may contribute, as can emotional stress. Fibromyalgia may be precipitated by a viral or other systemic infection (eg, Lyme disease) or a traumatic event, but additional or prolonged antiviral or antibiotic therapy is not indicated because it is not effective.
Stiffness and pain frequently begin gradually and diffusely and have an achy quality. Pain is widespread and may worsen with fatigue, muscle strain, or overuse.
Patients typically have a variety of somatic symptoms. Fatigue is common, as are cognitive disturbances such as difficulty concentrating and a general feeling of mental cloudiness. Many patients also have symptoms of irritable bowel syndrome, interstitial cystitis, or migraine or tension headaches. Paresthesias may be present, typically bilaterally.
Symptoms can be exacerbated by environmental or emotional stress, poor sleep, trauma, exposure to dampness or cold, or by a physician, family member, or friend who implies that the disorder is “all in the head.”
Patients tend to be stressed, tense, anxious, fatigued, ambitious, and sometimes depressed. Patients are not uncommonly high-achieving perfectionists.
Physical examination is unremarkable except that specific, discrete areas of muscle (tender points) often are tender when palpated. The tender areas are not swollen, red, or warm; such findings should suggest an alternative diagnosis.
Fibromyalgia is suspected in patients with the following:
The diagnosis of fibromyalgia should be considered in people who have had widespread pain for at least 3 months, particularly when accompanied by various somatic symptoms. Pain is considered widespread when patients have pain in the left and right side of the body, above and below the waist, and in the axial skeleton (cervical spine, anterior chest or thoracic spine, or low back).
The diagnosis is based on clinical criteria from the American College of Rheumatology (1), which include a combination of widespread pain and the presence of various other cognitive and somatic symptoms, such as those listed above, which are graded in severity. Previous criteria relied on the presence of tenderness at some of 18 specified tender points. This criterion was eliminated because nonspecialists sometimes have difficulty evaluating tenderness consistently, the tender points may fluctuate in intensity, and it was thought advantageous to have criteria that are entirely symptom-based. However, tenderness is quite common, and some specialists continue to assess it systematically.
Tests for other causes of patient symptoms should include erythrocyte sedimentation rate (ESR) or C-reactive protein, creatine kinase (CK), and probably tests for hypothyroidism and hepatitis C (which can cause fatigue and generalized myalgias). Other tests (eg, serologic testing for rheumatic disorders) should be done only if indicated by findings on history and/or physical examination.
To avoid potential pitfalls, clinicians should consider the following:
Fibromyalgia is often overlooked in men, children, and adolescents.
Chronic fatigue syndrome (systemic exertion intolerance disease) can cause similar generalized myalgias and fatigue, and laboratory test results are typically normal.
Polymyalgia rheumatica causes more focused myalgias, particularly in older adults; it can be distinguished from fibromyalgia because it tends to affect proximal muscles selectively, is more symptomatic in the morning, and is usually accompanied by high ESR and C-reactive protein levels.
Fibromyalgia tends to be chronic but may remit spontaneously if stress decreases. It can also recur at frequent intervals. Functional prognosis is usually favorable for patients being treated with a comprehensive, supportive program, but symptoms tend to persist to some degree. Prognosis may be worse if there is a superimposed mood disorder that is not addressed.
Stretching exercises, aerobic exercises, sufficient sound sleep, local applications of heat, and gentle massage may provide relief. Overall stress management (eg, deep breathing exercises, meditation, psychologic support, counseling if necessary) is important.
Exercises to gently stretch the affected muscles should be done daily; stretches should be held for about 30 seconds and repeated about 5 times. Aerobic exercise (eg, fast walking, swimming, exercise bicycling) can lessen symptoms.
Improving sleep is critical. Sedating drugs can be taken but only at night and only to improve sleep. Low-dose oral tricyclic antidepressants at bedtime (eg, amitriptyline 10 to 50 mg, trazodone 50 to 150 mg, doxepin 10 to 25 mg) or the pharmacologically similar cyclobenzaprine 10 to 30 mg may promote deeper sleep and decrease muscle pain. The lowest effective dose should be used. Drowsiness, dry mouth, and other adverse effects may make some or all of these drugs intolerable, particularly for older patients.
Nonopioid analgesics (eg, acetaminophen, nonsteroidal anti-inflammatory drugs [NSAIDs]) may help some patients. Opioids should be avoided. Pregabalin, duloxetine, and milnacipran are available for treatment of fibromyalgia, but should be used as adjuncts to exercise, measures to improve sleep, and stress management; they may help modestly to reduce pain.
Occasional injections of 0.5% bupivacaine or 1% lidocaine 1 to 5 mL are used to treat incapacitating areas of focal tenderness, but such injections should not be relied on as primary treatment because evidence does not support their regular use.
Fibromyalgia-related stiffness and pain can be exacerbated by environmental or emotional stress, poor sleep, trauma, exposure to dampness or cold, or by a physician, family member, or friend who implies that the disorder is “all in the head.”
Suspect fibromyalgia when generalized pain and tenderness and fatigue are unexplained or out of proportion to physical and laboratory findings.
Consider checking erythrocyte sedimentation rate (ESR) or C-reactive protein, creatine kinase (CK), and tests for hypothyroidism and hepatitis C, and consider chronic fatigue syndrome and polymyalgia rheumatica. Do further testing for other rheumatologic diseases only if they are suggested by clinical evaluation.
Treat by emphasizing physical methods, stress management, and sleep improvement, and, when necessary for pain, by giving nonopioid analgesics.