Fibromyalgia

Fibromyalgia is mostly thought to be a centrally mediated disorder of pain sensitivity, although some recent studies have potentially implicated the peripheral nervous system as well, in the form of small fiber neuropathy. The exact cause is unknown, but it is thought to relate to disordered central nociceptive signal processing that leads to sensitization expressed as hyperalgesia (heightened pain response) and allodynia (pain from normally nonpainful stimuli) (1). Fibromyalgia is more commonly seen in individuals with other sleep disorders like sleep apnea (2). Fibromyalgia may temporally follow a viral or other systemic infection (eg, Lyme disease or perhaps COVID-19 infection [3]) or a traumatic event, but additional or prolonged antiviral or antibiotic therapy is not indicated because it has not been demonstrated to be 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. Paresthesias may be present, typically bilaterally and often migratory.

Symptoms can be exacerbated by concomitant disorders, particularly chronic pain conditions and psychiatric comorbidities. Chronic conditions that frequently coexist with fibromyalgia include inflammatory arthritis (eg, rheumatoid arthritis), irritable bowel syndrome, interstitial cystitis, migraine, tension headaches, temporomandibular disorder, or sleep disturbances in patients with obstructive sleep apnea or depression.

Patients may be stressed, tense, anxious, fatigued, and sometimes depressed.

Physical examination is unremarkable except that specific, discrete areas of muscle (tender points) are variably tender when palpated. The tender areas are not swollen, red, or warm; such findings should suggest an alternative diagnosis.

• Primarily history and physical examination

• Usually additional testing to exclude other disorders

Fibromyalgia is suspected in patients with the following:

• Generalized pain and tenderness, especially if disproportionate to physical findings

• Negative laboratory results despite widespread symptoms

• Fatigue as a predominant symptom

The diagnosis of fibromyalgia should be considered in people who have had widespread pain for at least 3 months, particularly when accompanied by other core somatic symptoms such as fatigue and sleep disturbance (1). 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 primarily on history and physical examination findings in the context of other core features, and in the absence of an alternative diagnosis. Clinicians may refer to clinical criteria that were primarily designed for research purposes but may be used to support their clinical judgement (1, 2). For example, the American College of Rheumatology criteria require that the patient have generalized pain in at least 4 of 5 body regions for at least 3 months in addition to meeting minimum thresholds on both a widespread pain index (WPI) and symptom severity score (1). Previous criteria relied on the presence of tenderness in at least 11 of 18 specified tender points (3). This approach was eliminated because of its failure to allow for the consistent evaluation of tenderness, the possible fluctuation in intensity of tender points, and the inability to capture the full spectrum of fibromyalgia symptoms. However, tenderness is quite common, and some specialists continue to assess it systematically.

Tests to exclude other causes of patient symptoms could include a complete blood count, comprehensive metabolic panel, erythrocyte sedimentation rate (ESR) or C-reactive protein, creatine kinase (CK), thyroid panel and tests for various autoimmune diseases and infections. However, these tests should be performed based on the clinical suspicion and not every test is recommended in each patient. Fibromyalgia does not cause abnormalities in these tests and hence these tests can be useful to exclude other differential diagnoses.

To avoid potential pitfalls, clinicians should consider the following:

• Fibromyalgia is often overlooked in men, children, and adolescents.

• Myalgia encephalomyelitis/chronic fatigue syndrome can cause similar generalized myalgias and fatigue, and laboratory test results are typically normal.

• Polymyalgia rheumatica causes more focal pain around the shoulders and hip girdle, particularly in older adults; it is more symptomatic in the morning and is usually accompanied by high ESR and C-reactive protein levels.

• In patients with systemic rheumatic diseases, diagnosing coexistent fibromyalgia may be more difficult, but it is quite common. For example, fibromyalgia may be misinterpreted as an exacerbation of rheumatoid arthritis, ankylosing spondylitis, or systemic lupus erythematosus.

• Stretching and aerobic exercise, local heat, and massage

• Stress management

• Medications such as tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, gabapentinoids, or cyclobenzaprinereuptake inhibitors, gabapentinoids, or cyclobenzaprine

• Evaluation for and treatment of other comorbidities (eg, underlying sleep disorders, depression)

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, psychological 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. Patients should be screened for sleep disorders (eg, obstructive sleep apnea) and other factors that may interfere with sleep. Good sleep hygiene should also be emphasized.

Pharmacologic therapies for fibromyalgia (eg, amitriptyline, duloxetine, cyclobenzaprine, milnacipran, and pregabalin) could be used as adjuncts to exercise to improve sleep and manage stress; they may modestly reduce pain (Pharmacologic therapies for fibromyalgia (eg, amitriptyline, duloxetine, cyclobenzaprine, milnacipran, and pregabalin) could be used as adjuncts to exercise to improve sleep and manage stress; they may modestly reduce pain (1). Sedating medications, such as low-dose oral tricyclic antidepressants (eg, amitriptyline 10 to 50 mg) or the pharmacologically similar cyclobenzaprine, are taken at bedtime and may promote deeper sleep and decrease muscle pain. The lowest effective dose should be used. A serotonin-). Sedating medications, such as low-dose oral tricyclic antidepressants (eg, amitriptyline 10 to 50 mg) or the pharmacologically similar cyclobenzaprine, are taken at bedtime and may promote deeper sleep and decrease muscle pain. The lowest effective dose should be used. A serotonin-norepinephrine reuptake inhibitor (eg, duloxetine) is a reasonable alternative, particularly for patients with severe fatigue and depression. Pregabalin and gabapentin may also be particularly useful for patients with more severe sleep problems. Drowsiness, dry mouth, and other adverse effects may make some or all of these medications intolerable, particularly for older patients.reuptake inhibitor (eg, duloxetine) is a reasonable alternative, particularly for patients with severe fatigue and depression. Pregabalin and gabapentin may also be particularly useful for patients with more severe sleep problems. Drowsiness, dry mouth, and other adverse effects may make some or all of these medications intolerable, particularly for older patients.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have not been shown to be effective in fibromyalgia (2). Opioids should be avoided.

Occasional injections of 0.5% bupivacaine or 1% lidocaine 1 to 5 mL may relieve incapacitating areas of focal tenderness, but such injections should not be relied on as primary treatment because evidence does not support their regular use, and does not address the widespread nociceptive pain associated with fibromyalgia (Occasional injections of 0.5% bupivacaine or 1% lidocaine 1 to 5 mL may relieve incapacitating areas of focal tenderness, but such injections should not be relied on as primary treatment because evidence does not support their regular use, and does not address the widespread nociceptive pain associated with fibromyalgia (3).

Medications taken by the patient should be reviewed to identify those that may aggravate sleep problems. Such medications should be avoided. Comorbidities such as anxiety, depression, and especially bipolar disorder, if present, should be addressed.

Fibromyalgia tends to be chronic, with symptoms persisting in severity for most patients (1). Functional prognosis is usually favorable for patients being treated with a comprehensive, supportive program, but symptoms tend to persist to some degree (2). Prognosis may be worse if there is a superimposed mood disorder that is not addressed.