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Improving the Recognition and Diagnosis of Fibromyalgia

      Fibromyalgia (FM) is a chronic widespread pain disorder often seen in primary care practices. Advances in the understanding of FM pathophysiology and clinical presentation have improved the recognition and diagnosis of FM in clinical practice. Fibromyalgia is a clinical diagnosis based on signs and symptoms and is appropriate for primary care practitioners to make. The hallmark symptoms used to identify FM are chronic widespread pain, fatigue, and sleep disturbances. Awareness of common mimics of FM and comorbid disorders will increase confidence in establishing a diagnosis of FM.
      ACR (American College of Rheumatology), CRP (C-reactive protein), ESR (erythrocyte sedimentation rate), FM (fibromyalgia), RA (rheumatoid arthritis)
      Fibromyalgia (FM), a chronic widespread pain disorder, is estimated to affect more than 5 million Americans (2%-5% of the adult population).
      • Wolfe F
      • Ross K
      • Anderson J
      • Russell IJ
      • Hebert L
      The prevalence and characteristics of fibromyalgia in the general population.
      • Lawrence RC
      • Felson DT
      • Helmick CG
      • et al.
      Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II.
      • Burckhardt CS
      • Goldenberg D
      • Crofford L
      • et al.
      It is second only to osteoarthritis as the most common disorder seen in rheumatology practices.
      • Goldenberg DL
      • Burckhardt C
      • Crofford L
      Management of fibromyalgia syndrome.
      In recent years, increasingly more patients with FM are presenting to primary care clinicians for initial diagnosis and ongoing care.
      Fibromyalgia is a persistent and potentially debilitating disorder that can have a devastating effect on quality of life, impairing the patient's ability to work and participate in everyday activities, as well as affecting relationships with family, friends, and employers.
      • Arnold LM
      • Crofford LJ
      • Mease PJ
      • et al.
      Patient perspectives on the impact of fibromyalgia.
      It imposes heavy economic burdens on society as well as on the patient.
      • Berger A
      • Dukes E
      • Martin S
      • Edelsberg J
      • Oster G
      Characteristics and healthcare costs of patients with fibromyalgia syndrome.

      Goldenberg D, Schaefer C, Ryan K, Chandran A, Slateva G. What is the true cost of fibromyalgia to our society: results from a cross-sectional survey in the United States. Paper presented at: American College of Rheumatology; Philadelphia, PA: October 18, 2009.

      Recent research suggests that the chronic widespread pain that is the hallmark symptom of FM is neurogenic in origin.
      • Russell IJ
      • Larson AA
      Neurophysiopathogenesis of fibromyalgia syndrome: a unified hypothesis.
      Fibromyalgia is associated with a central amplification of pain perception characterized by allodynia (ie, a heightened sensitivity to stimuli that are not normally painful) and hyperalgesia (ie, an increased response to painful stimuli). Neuroimaging studies have also shown that FM is associated with aberrant processing of painful stimuli in the central nervous system.
      • Gracely RH
      • Petzke F
      • Wolf JM
      • Clauw DJ
      Functional magnetic resonance imaging evidence of augmented pain processing in fibromyalgia.
      • Nebel MB
      • Gracely RH
      Neuroimaging of fibromyalgia.
      Accurate diagnosis is the critical first step to more effective care and better outcomes for patients with FM. Developed by the FibroCollaborative, a diverse group of leading experts on FM, this review aims to discuss the current understanding of FM symptomatology and diagnostic approaches. Methods for recognizing patients who may have FM on the basis of presentation of symptoms and associated disorders are described, as well as important steps in the differential diagnosis, including the role of the physical examination, laboratory testing, and referrals to specialists to identify both disorders that can mimic FM and those that frequently coexist with FM.

      UNDERDIAGNOSIS

      Despite improved understanding of its pathologic processes, FM remains undiagnosed in as many as 3 out of 4 people with the condition (Data on file. Decision Resources report 2009. Pfizer, New York, NY). Diagnosis time averages 5 years,
      • National Pain Foundation
      resulting in delayed treatment and potentially suboptimal medical care. Women currently account for 80% to 90% of cases diagnosed using the American College of Rheumatology (ACR) 1990 criteria for FM (prevalence, 3.4% in women vs 0.5% in men).
      • Wolfe F
      • Ross K
      • Anderson J
      • Russell IJ
      • Hebert L
      The prevalence and characteristics of fibromyalgia in the general population.
      Women are more sensitive to painful stimuli than men and therefore have a greater response than men to the diagnostic tender point examination that is included in the ACR criteria (tenderness on digital palpation at predesignated sites). As a result, men with chronic widespread pain rarely meet ACR criteria for FM, despite having a similar underlying pathologic process.
      • Clauw DJ
      Fibromyalgia: update on mechanisms and management.

      IMPORTANCE OF IMPROVED RECOGNITION AND DIAGNOSIS

      Establishing the diagnosis of FM is an essential component of successful management.
      • Goldenberg DL
      • Burckhardt C
      • Crofford L
      Management of fibromyalgia syndrome.
      Many patients with FM have been living with chronic pain and other troubling and disabling symptoms for extended periods. Primary care practices undoubtedly see more patients with FM than is currently appreciated. When such patients are finally recognized and a diagnosis is confirmed, both clinician and patient clear a major hurdle to more effective management of the disorder.
      Research shows that the diagnosis of FM has no negative effect on clinical outcomes. Indeed, patients newly diagnosed as having FM report improved satisfaction with health and fewer long-term symptoms.
      • White KP
      • Nielson WR
      • Harth M
      • Ostbye T
      • Speechley M
      Does the label “fibromyalgia” alter health status, function, and health service utilization? a prospective, within-group comparison in a community cohort of adults with chronic widespread pain.
      In addition, several studies have indicated that the utilization of medical resources and the associated costs decline after a diagnosis of FM.
      • Annemans L
      • Wessely S
      • Spaepen E
      • et al.
      Health economic consequences related to the diagnosis of fibromyalgia syndrome.
      • Hughes G
      • Martinez C
      • Myon E
      • Taieb C
      • Wessely S
      The impact of a diagnosis of fibromyalgia on health care resource use by primary care patients in the UK: an observational study based on clinical practice.
      Patients with FM appreciate sincere efforts to help them and can be gratifying to treat.
      The diagnostic evaluation of FM can take time, but this should not be a barrier in primary care practices. If a diagnosis of FM is suspected, a trial of treatment can begin while the evaluation for possible other coexisting disorders continues. Subsequent visits during initial diagnosis and management actually reassure the patient with FM that they are receiving appropriate care and validation, which can be very therapeutic.

      A PRACTICAL APPROACH TO RECOGNITION AND DIAGNOSIS

      Fibromyalgia is a clinical diagnosis based on the disorder's unique clinical characteristics and not solely a diagnosis of exclusion. Like other pain states (eg, migraine), FM is commonly diagnosed in the primary care setting on the basis of characteristic symptoms.
      A focused history and physical examination are the cornerstones of FM recognition. No laboratory or radiologic testing is required to diagnose FM. Such tests are necessary only if clinically indicated to evaluate other potential diagnoses, including conditions that may be comorbid with FM. Routine laboratory tests may help guide the assessment, especially if they have not been performed at some point in the patient's work-up. Specialist referral is usually not necessary to confirm the diagnosis. The goal is to identify FM and initiate treatment as early as possible, even if further evaluation is needed to identify and confirm possible comorbid conditions that may also require management.

      Patient History

      Core Symptoms of FM. The core symptoms of FM can be visualized as a triad that includes chronic widespread pain (in the right and left side of the body, above and below the waist, and in the axial skeleton) of long duration (≥3 months) as the primary, hallmark symptom, with fatigue
      • Mease PJ
      • Arnold LM
      • Crofford LJ
      • et al.
      Identifying the clinical domains of fibromyalgia: contributions from clinician and patient Delphi exercises.
      and sleep disturbance (including nonrestorative sleep [ie, feeling unrefreshed after a night's sleep])
      • Arnold LM
      • Crofford LJ
      • Mease PJ
      • et al.
      Patient perspectives on the impact of fibromyalgia.
      • Mease PJ
      • Arnold LM
      • Crofford LJ
      • et al.
      Identifying the clinical domains of fibromyalgia: contributions from clinician and patient Delphi exercises.
      as 2 other commonly associated symptoms. These 3 symptoms occur in most patients with FM. Presentation of chronic widespread pain for years, especially in the presence of fatigue and sleep disturbance, should raise suspicion for FM. For many patients, the fatigue commonly associated with FM is the most troublesome symptom and the one that leads them to seek medical attention.
      Other key associated symptoms include tenderness, stiffness, mood disturbances (eg, depression and/or anxiety), and cognitive difficulties (eg, trouble concentrating, forgetfulness, and disorganized thinking).
      • Bennett RM
      Clinical manifestations and diagnosis of fibromyalgia.
      • Choy EH
      • Mease PJ
      Key symptom domains to be assessed in fibromyalgia (outcome measures in rheumatoid arthritis clinical trials).
      • Glass JM
      Review of cognitive dysfunction in fibromyalgia: a convergence on working memory and attentional control impairments.
      • Williams DA
      • Schilling S
      Advances in the assessment of fibromyalgia.
      Fibromyalgia symptoms can wax and wane, varying in intensity from day to day and by physical location. Patients with FM frequently report impairment in multiple areas of function, especially physical function.
      • Arnold LM
      • Crofford LJ
      • Mease PJ
      • et al.
      Patient perspectives on the impact of fibromyalgia.
      Overall, patients with FM are a heterogeneous population. The impact of FM spans the continuum from patients who are mildly to moderately affected by FM symptoms to those who are more severely affected and have markedly impaired function and quality of life.
      Fibromyalgia should be considered in all patients with multiple regions of chronic pain (at a single point in time or during the course of their lifetime), especially if they report multiple somatic symptoms. Generally, the index of suspicion for FM should increase the longer the chronic widespread pain and other symptoms have been present, the more variable the symptoms seem, and the more body systems that are involved.
      Comorbid Disorders. The presence of common comorbid disorders can also raise suspicion for FM, and it is important for the clinician to ask about chronic widespread pain when presented with these associated conditions. Examples of common comorbid disorders include mood or anxiety disorders, which can precede the development of FM. The lifetime (both current and past) prevalence of these disorders with FM is high, with any lifetime anxiety disorder reported in 35% to 62% of patients, lifetime major depressive disorder in 58% to 86% of patients, and lifetime bipolar disorder in up to 11% of patients.
      • Arnold LM
      • Hudson JI
      • Keck PE
      • Auchenbach MB
      • Javaras KN
      • Hess EV
      Comorbidity of fibromyalgia and psychiatric disorders.
      • Thieme K
      • Turk DC
      • Flor H
      Comorbid depression and anxiety in fibromyalgia syndrome: relationship to somatic and psychosocial variables.
      The high frequency with which FM and mood and anxiety disorders occur together is most likely explained by pathophysiologic abnormalities common to both mood and anxiety disorders and FM, rather than by FM causing the mood and anxiety disorders or the mood and anxiety disorders causing FM.
      • Hudson JI
      • Pope Jr, HG
      The relationship between fibromyalgia and major depressive disorder.
      Although psychiatric disorders often occur together with FM, they should not be confused with FM or viewed as being the same disorder.
      • Thieme K
      • Turk DC
      • Flor H
      Comorbid depression and anxiety in fibromyalgia syndrome: relationship to somatic and psychosocial variables.
      As comorbid conditions, mood and anxiety disorders need to be treated together with FM, sometimes with different interventions. Treatment aimed at mood alone may result in suboptimal outcomes for the management of all of the symptoms of FM.
      • Williams DA
      • Clauw DJ
      Understanding fibromyalgia: lessons from the broader pain research community.
      Other common comorbid disorders in patients with FM include the following regional pain syndromes that may share certain pathophysiologic features with FM: irritable bowel syndrome, tension-type headache/migraine, interstitial cystitis or painful bladder syndrome, chronic prostatitis or prostadynia, temporomandibular disorder, chronic pelvic pain, and vulvodynia.
      • Williams DA
      • Clauw DJ
      Understanding fibromyalgia: lessons from the broader pain research community.
      • Ablin K
      • Clauw DJ
      From fibrositis to functional somatic syndromes to a bell-shaped curve of pain and sensory sensitivity: evolution of a clinical construct.
      Patients may focus on local areas of pain and describe one particularly bothersome area; others may hesitate to mention all of their pain symptoms, especially if some of their pain has been dismissed or discounted previously. Therefore, it is important for clinicians to determine whether pain is limited to 1 or more regions of the body or whether the pain is more widespread.
      Fibromyalgia Risk Factors. The patient's history may reveal risk factors for FM, such as familial predisposition. Relatives of people with FM are at a higher risk. In a recent family study, first-degree relatives of patients with FM were 8 times more likely to have FM than relatives of the control group of patients with rheumatoid arthritis (RA).
      • Arnold LM
      • Hudson JI
      • Hess EV
      • et al.
      Family study of fibromyalgia.
      Environmental factors, including physical trauma or injury, infections (eg, Lyme disease and hepatitis C), and other stressors (eg, work, family, life-changing events, and abuse history), pose additional risk.
      • Mease PJ
      • Clauw DJ
      • Arnold LM
      • et al.
      Fibromyalgia syndrome.
      Finally, sex is a risk factor. Women are diagnosed as having FM approximately 7 times more often than men; however, the source of at least some of this disparity appears to be an artifact of requiring a certain degree of tenderness to diagnose FM using ACR criteria.
      • Weir PT
      • Harlan GA
      • Nkoy FL
      • et al.
      The incidence of fibromyalgia and its associated comorbidities: a population-based retrospective cohort study based on International Classification of Diseases, 9th Revision codes.
      Medical History Tools. Tools are available to facilitate a focused medical history in the time-constrained primary care setting. The use of a body pain diagram during the initial examination can assist patients in documenting the presence of widespread pain and establish a baseline for monitoring treatment response. Patient screening can begin in the office waiting area using brochures that include a body pain diagram and a simple questionnaire, with questions such as the following: Have you had pain in your muscles or joints that has lasted 3 months or more? Do you have pain all over? Do you become fatigued during the day so that you have to stop normal activities? Do you wake up in the morning and feel more tired than when you went to bed?

      Physical Examination

      The physical examination of a patient with suspected FM should focus on identifying associated or comorbid disorders as warranted by symptoms, signs, and the medical history because these may require separate management. Joints should be examined for swelling, tenderness, range of motion, and crepitus, and patients should be evaluated for peripheral pain generators (eg, RA, osteoarthritis, tendonitis, adhesive capsulitis) as well as focal and/or objective weakness. If the history is suggestive, signs of connective tissue disease should be assessed and a neurologic examination conducted. It is important to note that the presence of a second disorder (even a painful one) does not necessarily exclude a diagnosis of FM, which can occur together with other painful conditions.
      • Arnold LM
      The pathophysiology, diagnosis and treatment of fibromyalgia.
      In general, the physical examination findings are normal in FM except for diffuse tenderness,
      • Goldenberg DL
      Fibromyalgia syndrome a decade later: what have we learned?.
      evaluated by counting tender points or by digital palpation of several regions of the body. The physical examination (regardless of whether tender points are counted) remains key in the evaluation of patients to assess the tenderness (allodynia and hyperalgesia) associated with FM as well as to aid in the differential diagnosis.

      FORMAL CLASSIFICATION CRITERIA

      The ACR criteria for FM (Figure 1) include a history of widespread pain lasting 3 months or longer.
      • Wolfe F
      • Smythe HA
      • Yunus MB
      • et al.
      The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee.
      Widespread pain is defined as pain above and below the waist and on both sides of the body. In addition, axial skeletal pain (in the cervical spine, anterior chest, thoracic spine, or lower back) must be present. According to the ACR, a patient must have pain on digital palpation at 11 of 18 predesignated sites, commonly referred to as tender points, to be diagnosed as having FM. Approximately 4 kg of pressure must be applied to a site, and the patient must indicate that the site is painful.
      • Okifuji A
      • Turk DC
      • Sinclair JD
      • Starz TW
      • Marcus DA
      A standardized manual tender point survey, I: Development and determination of a threshold point for the identification of positive tender points in fibromyalgia syndrome.
      In practical terms, the pressure to assess tenderness with digital examination is the pressure needed to see your own nail bed blanch.
      Figure thumbnail gr1
      FIGURE 1American College of Rheumatology 1990 criteria for the classification of fibromyalgia.
      Adapted from Arthritis Rheum,
      • Wolfe F
      • Smythe HA
      • Yunus MB
      • et al.
      The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee.
      with permission.
      The ACR criteria have a sensitivity of 88.4% and a specificity of 81.1%.
      • Wolfe F
      • Smythe HA
      • Yunus MB
      • et al.
      The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee.
      Many health care professionals find the manual tender point examination useful for confirming the presence of widespread tenderness and increasing confidence in the diagnosis.
      • Harth M
      • Nielson WR
      The fibromyalgia tender points: use them or lose them? a brief review of the controversy.
      These criteria were originally designed to standardize patient classification in clinical trials rather than to diagnose FM in routine clinical practice.
      • Clauw DJ
      Fibromyalgia: update on mechanisms and management.
      Nevertheless, the tender point examination has been used in hundreds of studies and is recognized by the ACR for the diagnosis of FM.
      As a possible alternative to the ACR criteria for use in clinical settings, Wolfe et al
      • Wolfe F
      • Clauw DJ
      • Fitzcharles MA
      • et al.
      The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.
      recently proposed clinical diagnostic criteria for FM that do not rely on counting tender points. The proposed criteria take into account not only pain but also other FM-related symptoms and are intended to assess the severity of those symptoms (Table 1).
      • Wolfe F
      • Clauw DJ
      • Fitzcharles MA
      • et al.
      The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.
      To administer the Widespread Pain Index and Symptom Severity scale, the physician asks the patient to report the locationof any pain during the past week at 19 sites, including areas of the shoulders, arms, hips, legs, jaws, chest, abdomen, back, and neck. The Symptom Severity scale focuses on 3 physical symptoms, as well as somatic symptoms in general. Fatigue, waking unrefreshed, and cognitive symptoms are rated on the basis of the level of severity during the previous week. Table 1 summarizes typical somatic symptoms that might be considered.
      • Wolfe F
      • Clauw DJ
      • Fitzcharles MA
      • et al.
      The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.
      Research to determine the clinical usefulness of these proposed criteria is ongoing. Studies of other approaches to the identification of patients with FM in primary care settings are also under way. Many clinicians also use the previously described core symptoms to identify patients with FM.
      TABLE 1Clinical Diagnostic and Severity Criteria for Fibromyalgia: Widespread Pain Index (WPI) and Symptom Severity (SS) Scale
      Adapted from Arthritis Care Res (Hoboken),
      • Wolfe F
      • Clauw DJ
      • Fitzcharles MA
      • et al.
      The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.
      with permission.
      • Criteria
        • A patient satisfies diagnostic criteria for fibromyalgia if the following 3 conditions are met:
          • WPI ≥7 and SS scale score ≥5 or WPI 3–6 and SS scale score ≥9
          • Symptoms have been present at a similar level for at least 3 months
          • The patient does not have a disorder that would otherwise explain the pain
      • Ascertainment
        • WPI (0–19)—Directions: Note the number of areas in which the patient has had pain during the past week. In how many areas has the patient had pain?
      Shoulder girdle, leftHip (buttock, trochanter), leftJaw, leftUpper back
      Shoulder girdle, rightHip (buttock, trochanter), rightJaw, rightLower back
      Upper arm, leftUpper leg, leftChestNeck
      Upper arm, rightUpper leg, rightAbdomen
      Lower arm, leftLower leg, left
      Lower arm, rightLower leg, right
      • SS scale score (0–12) = Symptom Severity + Extent of Somatic Symptoms
        • Symptom severity—Directions: Using the provided scale, indicate the level of severity experienced for each of the 3 following symptoms:
          • Fatigue
          • Waking unrefreshed
          • Cognitive symptoms
        • Scale
          • 0 = no problem
          • 1 = mild: slight, mild, or intermittent problems
          • 2 = moderate: considerable problems, often present and/or at a moderate level
          • 3 = severe: pervasive, continuous, life-disturbing problems
        • Extent of somatic symptoms—Directions: Indicate how many somatic symptoms
          Somatic symptoms that might be considered include muscle pain, irritable bowel syndrome, fatigue/tiredness, thinking or remembering problems, muscle weakness, headache, pain/cramps in abdomen, numbness/tingling, dizziness, insomnia, depression, constipation, pain in upper abdomen, nausea, nervousness, chest pain, blurred vision, fever, diarrhea, dry mouth, itching, wheezing, Raynaud phenomenon, hives/welts, ringing in ears, vomiting, heartburn, oral ulcers, loss/change in taste, seizures, dry eyes, shortness of breath, loss of appetite, rash, sun sensitivity, hearing difficulties, easy bruising, hair loss, frequent urination, painful urination, and bladder spasms.
          the patient has using the following scale
          • 0 = no symptoms
          • 1 = few symptoms
          • 2 = a moderate number of symptoms
          • 3 = a great deal of symptoms
      a Somatic symptoms that might be considered include muscle pain, irritable bowel syndrome, fatigue/tiredness, thinking or remembering problems, muscle weakness, headache, pain/cramps in abdomen, numbness/tingling, dizziness, insomnia, depression, constipation, pain in upper abdomen, nausea, nervousness, chest pain, blurred vision, fever, diarrhea, dry mouth, itching, wheezing, Raynaud phenomenon, hives/welts, ringing in ears, vomiting, heartburn, oral ulcers, loss/change in taste, seizures, dry eyes, shortness of breath, loss of appetite, rash, sun sensitivity, hearing difficulties, easy bruising, hair loss, frequent urination, painful urination, and bladder spasms.
      Once FM is diagnosed, treatment should begin even if further evaluation for comorbid conditions is ongoing. Identification of disorders that coexist with FM may help to reveal contributing factors that may need to be addressed in the comprehensive management plan.

      DIFFERENTIAL DIAGNOSIS

      Current medications should be identified and medication-related pain such as statin-induced muscle pain or opioid-induced hyperalgesia ruled out. Identification of disorders that can mimic FM (eg, hypothyroidism and inflammatory rheumatic diseases) or that are frequent comorbid conditions in patients with FM (eg, RA, osteoarthritis, systemic lupus erythematosus, spinal stenosis, neuropathies, sleep disorders such as sleep apnea, and mood and anxiety disorders) is essential so that appropriate treatments can be initiated.
      • Yunus MB
      A comprehensive medical evaluation of patients with fibromyalgia syndrome.
      The presence of a second disorder does not exclude a diagnosis of FM; both disorders will need management.

      Laboratory Testing

      Extensive laboratory testing is not generally necessary to diagnose FM.
      • Yunus MB
      A comprehensive medical evaluation of patients with fibromyalgia syndrome.
      A diagnosis of FM can be established on the basis of the history and physical examination findings with selective use of laboratory testing.
      Although not required to establish the diagnosis of FM, routine laboratory testing (if not already performed within the past 6-12 months) is frequently obtained to evaluate other possible causes of symptoms or signs. These tests include measurement of erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) levels, a complete blood cell count, a comprehensive metabolic panel, and a thyroid function test. Routine testing for rheumatoid factor or antinuclear antibodies is not recommended to diagnose FM unless the patient has signs or symptoms suggesting an autoimmune disorder, or if initial inflammatory indices (ie, ESR and/or CRP level) are abnormal (recognizing that some patients with RA or systemic lupus erythematosus may have normal ESR and/or CRP values). Depending on symptoms (eg, duration of pain and acute vs chronic), medical history, and physical examination findings, other tests, such as measurement of ferritin, vitamin B12, and vitamin D levels and determination of iron-binding capacity and percentage of saturation, may be indicated.
      • Yunus MB
      A comprehensive medical evaluation of patients with fibromyalgia syndrome.

      Further Investigation/Specialist Referral

      A diagnosis of FM can be established appropriately in the primary care setting, but specialist referral may be indicated. The patient should be referred for specialist evaluation if uncertainty remains about the diagnosis because of unusual symptoms or signs, disease course, laboratory findings, or other concerns. Referral should also occur when the patient has abnormal laboratory results that suggest another condition requiring specialty care. It may also be necessary for the treatment of comorbid conditions, including mood/anxiety and sleep disorders. Figure 2 and Table 2 summarize the approach to the diagnosis of FM.
      Figure thumbnail gr2
      FIGURE 2Flow chart for the diagnosis of fibromyalgia (FM). ACR = American College of Rheumatology; PE = physical examination; SS = Symptom Severity; WPI = Widespread Pain Index.
      TABLE 2Differentiating Selected Disorders From Fibromyalgia
      ACR = American College of Rheumatology; ANA = antinuclear antibody; anti-CCP = anticyclic citrullinated peptide antibody; CPK = creatine phosphokinase; CRP = C-reactive protein; DIP/PIP = distal interphalangeal/proximal interphalangeal; EMG = electromyography; ESR = erythrocyte sedimentation rate; RF = rheumatoid factor; TSH = thyroid-stimulating hormone.
      DisorderClinical presentationTypical characteristicsDiagnostic tests
      No laboratory tests are required to establish the diagnosis of fibromyalgia.
      FibromyalgiaChronic widespread pain, sleep disturbance, fatigue, mood symptoms, other somatic symptomsFemale predominance (7–9: 1
      Ratio of female to male patients.
      )
      ACR tender point examination
      Onset: 25–60 y (may occur in adolescents)Laboratory results typically within normal limits
      Prevalence: 2%-5% of adults
      Myofascial pain syndromeLocalized muscle pain arising from trigger points, muscle stiffness, sleep disturbanceNo sex predominancePalpation of trigger points
      Onset: all ages
      Prevalence: 45%-54% of adults
      OsteoarthritisStiffness, gelling, crepitus, joint pain (knee, hip, hand)Onset: increases with ageRadiography
      Prevalence: ∼9% of adultsDIP/PIP nodules
      HypothyroidismWeight gain, cold intolerance, fatigue, muscle achesFemale predominance (2–8:1
      Ratio of female to male patients.
      )
      Serum TSH
      Prevalence: ∼5% of adults
      Rheumatoid arthritisSymmetric swelling of joints, insidious onset, morning stiffness (>1 h)Female predominance (2–3:1
      Ratio of female to male patients.
      )
      RF, anti-CCP, ESR, CRP, radiography
      Onset: 30–50 y
      Prevalence: ∼0.5% to 1% of adults
      Polymyalgia rheumaticaWeakness, pain in girdle muscles (neck, shoulders, thighs), stiffnessFemale predominance (2:1
      Ratio of female to male patients.
      )
      ESR, CRP, response to corticosteroids
      Onset: >50 y
      Prevalence: ∼0.2% of adults
      Systemic lupus erythematosusPhotosensitivity, fever, rash, fatigue, joint/muscle painFemale predominance (9:1
      Ratio of female to male patients.
      )
      ANA, ESR, CRP, anti-DNA
      Onset: 16–55 y
      Prevalence: ∼0.05% of adults
      PolymyositisSymmetric, proximal muscle weakness and painFemale predominance (2–3:1
      Ratio of female to male patients.
      )
      CPK, EMG
      Onset: >20 y (especially 45–60 y)
      Prevalence: ∼0.005%-0.01% of adults
      a ACR = American College of Rheumatology; ANA = antinuclear antibody; anti-CCP = anticyclic citrullinated peptide antibody; CPK = creatine phosphokinase; CRP = C-reactive protein; DIP/PIP = distal interphalangeal/proximal interphalangeal; EMG = electromyography; ESR = erythrocyte sedimentation rate; RF = rheumatoid factor; TSH = thyroid-stimulating hormone.
      b No laboratory tests are required to establish the diagnosis of fibromyalgia.
      c Ratio of female to male patients.

      CONCLUSION

      Fibromyalgia can have a profound effect on a patient's quality of life. Despite greater interest in and awareness of the disorder than ever before, FM remains underdiagnosed and undertreated. A greatly improved understanding of FM and its pathophysiologic underpinnings has helped explain the varied and often complex constellation of FM signs and symptoms, resulting in effective new treatment approaches.
      Fibromyalgia is a clinical diagnosis that, similar to other chronic pain states such as migraine, is appropriate for primary care practitioners to make. Although routine laboratory work can help guide the assessment, laboratory or radiologic testing is required only if clinically indicated for a concomitant disorder. Presentation of some of the hallmark symptoms (eg, chronic widespread pain, fatigue, and sleep disturbances) should raise suspicion for FM. A structured and focused medical history and physical examination can help in the differential diagnosis and confirm the diagnosis of FM.
      Better health outcomes and quality of life can be achieved by patients with FM with effective treatments developed as a result of an enhanced understanding of the disorder. Clinicians, both individually and in collaboration with other health care professionals and their patients, can improve patient care with vigilant recognition and diagnosis of FM.

      Acknowledgments

      Editorial support was provided by Dr Gayle Scott, PharmD, of UBC Scientific Solutions and funded by Pfizer.

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