Fibromyalgia is a common but poorly understood pain syndrome that usually affects muscles, tendons, and ligaments, without evidence of inflammation. The etiology and pathophysiology are unclear.[1] Some reports suggest the syndrome begins after trauma or illness.[2] It is most common in women 25-50 years of age, but it can also be seen in men and children.[3],[4]

Patients’ histories and examinations present no explanation for the persistent pain. The condition may be related to an abnormality in pain perception.[5] The most plausible hypothesis is that it occurs in genetically predisposed individuals who develop a heightened sense of pain and hypersensitivity to numerous stimuli.[6]

Nearly every fibromyalgia patient complains of fatigue, along with poor sleep quality that may include sleep apnea or other sleep abnormalities. One notable sleep abnormality is alpha wave intrusions in delta sleep.[7] Other common concurrent illnesses include irritable bowel syndrome, depression or anxiety, and headache.[8],[9] Many other nonspecific symptoms may occur, including glossodynia (a burning or tingling sensation of the lips, tongue, or entire mouth), paresthesias without dermatomal distribution, environmental sensitivity (chemical and allergic), and difficulty concentrating.[10]

Risk Factors

Gender. The condition is 10 times more common in women than in men.

Age. Incidence increases with age and peaks during middle age. The overall prevalence in the United States is approximately 2%, but many older adult populations have a prevalence approaching 10%.[2],[7]

Genetic Factors. Specific genes relating to abnormal serotonin metabolism and transmission have been identified in fibromyalgia patients.[11]

Diagnosis

For diagnosis, pain should be diffuse, lasting more than 3 months. Screening for psychiatric conditions is appropriate, but a positive diagnosis does not exclude fibromyalgia as a separate diagnosis.

Physical examination reveals characteristic, symmetrical tender points. Palpation of these areas causes pain that is disproportionate to the intensity of palpation. Apart from muscle and tendon pain, the examination is otherwise normal except in individuals with coexisting conditions, such as rheumatoid arthritis, osteoarthritis, and/or systemic lupus erythematosus.

The American College of Rheumatology (ACR) Classification Criteria for Fibromyalgia published in 1990 require tenderness in 11 of 18 tender points.[12] Pressure should be applied gradually and with a dolorimeter (4 kg/cm), or by using a finger to the point of blanching of the fingertip. The following tender points should be palpated bilaterally: superolateral quadrant of the gluteus maximus, supraspinatus origin, superior half of the trapezius, suboccipital insertion, sternocleidomastoid (posteroinferior), second costochondral junction, lateral epicondyle (approximately 2 cm distal), greater trochanter, and the medial knee (fat pad).

As a simpler alternative, the 2010 ACR diagnostic criteria allow for the omission of the evaluation of tender points as part of fibromyalgia diagnosis and rely instead on the symptom history.[13],[14] In 2011 another modification to the criteria was made.[15],[16] Both the 2010 and 2011 updates use a widespread pain index (WPI) and a symptom severity (SS) scale to make the fibromyalgia diagnosis.

Criteria needed for a fibromyalgia diagnosis:

1. Pain and symptoms over the past week, based on the total of number of painful areas out of 19 parts of the body plus level of severity of these symptoms:

a. Fatigue
b. Waking unrefreshed
c. Cognitive (memory or thought) problems

2. Symptoms lasting at least three months at a similar level

3. No other health problem that would explain the pain and other symptoms

No abnormal laboratory or imaging findings are diagnostic of fibromyalgia, and inappropriate tests can lead to misdiagnosis. Useful initial laboratory tests include complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), which are usually normal due to lack of tissue inflammation. Thyroid function tests, Lyme disease titer, and creatine kinase could also help rule out other etiologies. In appropriate at-risk individuals, vitamin D levels should be checked to rule out metabolic diseases, such as osteomalacia.[17]

Treatment

No single intervention is curative. However, multiple complementary modalities, along with consistent encouragement and reassurance by the physician can be very helpful. Commonly used treatments include both nonpharmacologic and drug therapies.

Nonpharmacologic Interventions

It is helpful to educate the patient and family members about the disease: the fact that its etiology is unclear but that it is not life-threatening, the various treatment options, and the importance of good sleep hygiene for pain management.[4],[18]

It is also important to treat any organic conditions that might exacerbate the pain.

Low-impact, incremental, cardiovascular exercise, three times weekly, can be helpful, as are muscle-strengthening and flexibility programs.[19] Yoga can serve both purposes.[20]

Hypnotherapy, cognitive behavioral therapy, electromyography (EMG) biofeedback, and meditation programs can be useful.

Acupuncture, TENS (transcutaneous electro-nerve stimulator) units, and trigger point needling (or injections with lidocaine) are under investigation.[21]

Pharmacologic Interventions

Nonsteroidal anti-inflammatory drugs are no better than placebo when used as monotherapy. However, they may be effective in combination with centrally acting medications.

Acetaminophen and/or tramadol in medication-naïve patients may be helpful, but efficacy in other clinical scenarios requires further study.

Tricyclic antidepressants, such as amitriptyline, benefit only a minority of patients.[22],[23] Cyclobenzaprine can be used in patients with mild to moderate symptoms. Efficacy may diminish over time. Small doses with gradual increases are advised, due to undesirable side effects (e.g., dry mouth, urinary retention). Desipramine may have milder adverse side effects.

Selective serotonin reuptake inhibitors may be effective in treating pain and may act synergistically with tricyclics.[24]

The US Food and Drug Administration has approved three drugs for the treatment of fibromyalgia. Two of these (duloxetine, marketed as Cymbalta, and milnacipran, marketed as Savella) act on neurotransmitters (serotonin and norepinephrine) that modulate pain perception. Duloxetine can be used in patients who do not improve or who do not tolerate amitriptyline, while milnacipran can be used instead of duloxetine in patients with severe fatigue as well as pain.[25],[26] The third, pregabalin (Lyrica), blocks the overactivity of nerve cells involved in pain transmission. Gabapentin (Neurontin) works by a similar mechanism.

Muscle relaxants, such as carisoprodol used at bedtime, may be beneficial. Narcotics and benzodiazepines are usually contraindicated.

A multidisciplinary approach that includes physical therapy, good sleep hygiene, and mental health specialists may be indicated for optimal treatment because concomitant depressive symptoms and adjustment problems are often present. Patients also benefit from knowing that a hidden condition is not the cause of their symptoms.[27],[28]

Fibromyalgia patients often have disturbed sleep and, in some cases, have lower nocturnal melatonin production, which can increase daytime fatigue and pain perception.[29] Limited evidence indicates that supplemental melatonin (3-5 mg at bedtime) reduces tender points, pain severity, and sleep disturbances and results in improvement in both patient and physician assessment of global improvement.[30],[31] Further studies are needed to assess the effects of melatonin supplements.

Nutritional Considerations

Although inflammatory cytokines (e.g., interleukin-6, interleukin-8) may be involved in triggering or increasing fibromyalgia symptoms, fibromyalgia is not considered to be an autoimmune disease.[32] Markers of increased oxidative stress (malondialdehyde, advanced glycosylation end products) and lower levels of the antioxidant enzyme superoxide dismutase have been found in patients with fibromyalgia.[33],[34] Dietary manipulation can reduce oxidative stress and cytokine production (see Rheumatoid Arthritis chapter), but such treatments have yet to be adequately tested in fibromyalgia patients.

In overweight fibromyalgia patients, weight loss has been shown to reduce symptoms.[35]

Limited evidence suggests that a vegan diet composed of mostly raw foods rich in antioxidants and fiber, along with probiotics, may improve subjective experience of joint pain and stiffness.[36],[37] Recent limited evidence also shows pain remission on a gluten-free diet in persons with long-standing, chronic fibromyalgia. These impressions require confirmation in additional controlled clinical trials.

Limited evidence suggests that oral vitamin D supplementation might be helpful in reducing the pain of fibromyalgia patients with vitamin D deficiency.[38]

Some studies have investigated possible roles of trace elements (e.g., zinc, magnesium), due to their importance in energy production and antioxidant activity, but findings in clinical trials with fibromyalgia patients have been inconsistent.[39]

Orders

See Basic Diet Orders.

Exercise prescription. Patient should be given an appropriate, sustainable, and enjoyable exercise routine.

What to Tell the Family

Fibromyalgia is a poorly understood condition that is treated symptomatically. General recommendations for a healthy exercise routine may be helpful to the patient and the entire family. Concomitant depression or other mental illness should be treated. Good sleep hygiene is also very important. Limited evidence suggests that some patients may respond well to a low-fat, vegan diet.

References