Fibromyalgia is a complex chronic pain disorder that affects 2% to 4% of the population.1 Patients with fibromyalgia may present with chronic, widespread pain and stiffness as well as a range of fluctuating associated symptoms.1,2 Patients may experience neurologic (tingling, dizziness, headache and migraine, brain ‘fog’), constitutional (sleep disturbance, weight change, fatigue), musculoskeletal (pain, stiffness, weakness), gastrointestinal (irritable bowel syndrome, nausea), and psychological (irritability, depression, anxiety) symptoms.1,2
However, fibromyalgia is not a diagnosis of exclusion and relies on thorough history-taking and physical examination. The diagnostic process can be challenging and frustrating to patients and clinicians. Once a patient is diagnosed, management goals include controlling and/or decreasing pain, fatigue, and depression associated with the disease and improving overall function and quality of life. Treatment is individualized to a patient’s needs and includes pharmacologic and nonpharmaceutical options.
Clinical Presentation and Diagnosis
In 2011, the American College of Rheumatology (ACR) proposed revised diagnostic criteria for fibromyalgia.3 These criteria used 2 widely known pain scales: the Widespread Pain Index (WPI) and the Symptom Severity Score (SSS). The WPI measures pain scores in 19 locations throughout the body using a score range of 0 to 19, and the SSS assesses fatigue, non-restorative sleep, cognitive symptoms, and a combination of these criteria using a score range of 0 to 12.3
Despite the update, experts remained concerned about the validity of these new diagnostic criteria due to their lack of diagnostic specificity and inability to help clinicians identify a cause of the disease.2,4 As a result, further revisions were made in 2016, when the ACR reintroduced a widespread pain criterion defined by pain in at least 4 of 5 body regions (not including jaw, chest, or abdomen).4
The current ACR diagnostic criteria require the presence of widespread pain for a minimum of 3 months and either a WPI score of ≥7 and an SSS score of ≥5 or a WPI of 4 to 6 and SSS score of ≥9.4 According to the authors, “This revision combines physician and questionnaire criteria, minimizes misclassification of regional pain disorders, and eliminates the previously confusing recommendation regarding diagnostic exclusions.”4
Palpation of trigger points, a component of the 1990 ACR guidelines, is optional for diagnosis under the current guidelines, but the presence of tenderness on palpation likely would help validate the diagnosis.5 Further diagnostic testing may be beneficial to rule out other comorbid conditions, such as rheumatoid arthritis, but the absence of findings related to comorbid diseases does not exclude a diagnosis of fibromyalgia because there are no specific diagnostic tests for the condition.6
Blood tests, including the FDA-compliant FM/a Test (EpicGenetics) and IsolateFibromyalgia test (IQuity), show promise for diagnosing fibromyalgia, but more supporting evidence is needed before these tests can be considered part of the work-up.
Other suggested diagnostic evaluations include complete blood count, basic metabolic panel, liver function tests, measurement of C-reactive protein levels or erythrocyte sedimentation rate, and thyroid function tests. Autoimmune screening tests should be performed only if there is a strong clinical suspicion of an inflammatory autoimmune condition.5
Management Framework for FM
There is no cure for fibromyalgia; therefore, the treatment goals are to manage the pain, fatigue, and depression associated with the condition and improve patient function. Clinicians should educate patients about their chronic condition, considering an individualized management plan to address each patient’s symptoms.
Although there is no clear pathophysiologic mechanism for fibromyalgia, evidence suggests that patients have an abnormality in central pain processing.5,7,8 Centralized pain, also referred to as central pain, central sensitization, or nociplastic pain, includes any chronic pain disorder with no identifiable mechanism of action outside the central nervous system. The International Association for the Study of Pain (IASP) has defined nociplastic pain as “pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain.”9
Management of fibromyalgia pain is different from that of other pain conditions, such as many types of arthritis, and both nonpharmacologic and pharmacologic options should be considered. All patients with fibromyalgia are encouraged to engage in regular cardiovascular exercise and stress reduction interventions and have good sleep hygiene. Patients also may benefit from cognitive-behavioral therapy (CBT), biofeedback, relaxation therapy, or other forms of counseling.10,11 Complementary medicine approaches, such as acupuncture and correction of nutritional deficiencies, are growing in popularity, despite a lack of good evidence supporting their efficacy. Although nonpharmacologic interventions are the first line of treatment and can be efficacious, patient non-compliance, especially with respect to physical activity, can limit their success. Evidence guidelines recommend at least 2 nonpharmacologic therapies (eg, CBT and exercise) combined with pharmacologic treatments for the management of fibromyalgia.11