52 - Fibromyalgia
Transcription
52 - Fibromyalgia
52 Fibromyalgia FREDERICK WOLFE • JOHANNES J. RASKER KEY POINTS Many issues that surround fibromyalgia are not scientific ones—it is widely agreed that pain and suffering are real; instead, the primary issues are often social, political, and financial. Fibromyalgia lies at the end of a continuum of polysymptomatic distress rather than being a discrete disorder. Fibromyalgia may be diagnosed with American College of Rheumatology (ACR) 2010 or 1990 criteria, but clinical care does not require a diagnosis. The ACR 2010 criteria should result in changes in the sex ratio of patients with fibromyalgia because men have higher pain thresholds and are therefore less likely to be diagnosed as having fibromyalgia than women when the 1990 criteria including tender points are used. Advanced neuroimaging techniques showed dysfunctioning of hippocampus and other cerebral abnormalities in fibromyalgia patients, as well as greater gray matter loss than in healthy controls. The regions in which objective changes are demonstrated may be functionally linked to core features of the disorder including affective disturbances and chronic widespread pain. Advanced neuroimaging techniques indicate that central factors are important in the processing of pain in people with fibromyalgia and suggest that they have a narrow range of tolerance for pain and perhaps other sensory stimuli before it becomes noxious. Pharmacologic treatment is of limited value, but caring, comprehensive care can make a difference. Fibromyalgia is a controversial disorder.1 Certain aspects of the controversies surrounding fibromyalgia reflect scientific disagreements about categorization, pathophysiology, and treatment (Figure 52-1). But another important reason for controversy is that the diagnosis carries with it profound societal consequences. Whether fibromyalgia “exists” or is “real” or should be valued matters a great deal to patients, payers, pension systems, researchers, professional and patient organizations, and pharmaceutical companies.2 Fibromyalgia is a clinical syndrome that is defined by the presence of generalized pain, fatigue, unrefreshed sleep, multiple somatic symptoms, cognitive problems, and other symptoms, often including depression. Symptoms important to the fibromyalgia case definition are shown in Figure 52-2 in order of their importance.3 The 2010 American College of Rheumatology (ACR) preliminary diagnostic criteria for fibromyalgia require the presence of widespread pain and multiple symptoms (Table 52-1).3 The more restrictive ACR 1990 classification criteria require the presence of widespread pain plus the presence of tenderness on palpation in at least 11 of 18 specified “tender point” sites.4 Fibromyalgia can be diagnosed in the presence of other medical conditions and is never a diagnosis of exclusion. However, concomitant disorders associated with musculoskeletal pain and fatigue will always need to be identified. THE FIBROMYALGIA CONSTRUCT One Syndrome or One of Many? The central features of fibromyalgia that were noted earlier are also found in illnesses such as chronic fatigue syndrome, irritable bowel syndrome, headache syndromes, and multiple chemical sensitivities, among many others (see Figure 52-1).5 Taken together, these syndromes have been called functional somatic syndromes (FSS).6 Because the symptom content of the syndromes is similar, as are the treatments and the demographic characteristics of patients who have the disorders, it has been suggested by many that a single diagnostic term, rather than individual syndrome names, should be used for diagnosis. These suggestions derive mostly from the psychiatric literature.7-9 Terms suggested include FSS and bodily pain disorder.9 However, if fibromyalgia is just a name given to the disorder primarily by rheumatologists, but does not differ essentially from other somatic syndromes, then fibromyalgia does not exist as a separate syndrome. Fibromyalgia versus FSS creates a series of problems. FSS connotes a strong psychologic component, which is undesirable to patients, pharmaceutical companies, and medical researchers. In addition, there is the logical inconsistency in which regulatory authorities such as the U.S. Food and Drug Administration (FDA) approve treatments for the select fibromyalgia indication, when fibromyalgia is not different from other FSS. The FDA mandate strengthens the position of fibromyalgia as a “separate” disease, although there is little evidence that it is such an entity.7,10 A Separate Syndrome or Part of a Continuum? Fibromyalgia is properly considered to lie “at the extreme end of the spectrum of polysymptomatic distress.”11 Fibromyalgia diagnosis depends on splitting the distress continuum, placing on one side of the divide those with fibromyalgia and on the other side all other persons. Poly symptomatic distress refers to problems in many symptom areas—pain, fatigue, sleep disturbance, functional impairment, psychologic status, and so on. Because symptoms are correlated, persons with high levels of one symptom will 733 734 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN Functional Somatic Syndromes One syndrome or many? Irritable Bowel Syndrome Chronic Fatigue Chronic Pelvic Pain TMJ Noncardiac Chest Pain Multiple Chemical Sensitivities Tension Headache Fibromyalgia Does central sensitization explain FM and CSS? Continuous Disorder Central Sensitization A continuum or a separate disorder? Somatization and Psychological Mechanisms How should FM and FSS be treated? Discrete Disorder What constitues treatment? A socially constructed disorder? • Societal Interaction • Social Construction • Medicalization • Pharma and Disease Mongering Is treatment effective? Figure 52-1 Fibromyalgia controversies. CSS, central sensitivity syndrome; FM, fibromyalgia; FSS, functional somatic syndromes; TMJ, temporomandibular joint. WPI (C) Muscle tenderness Muscle pain Somatic symptoms (C) Cognition (C) IBS Unrefreshed sleep (C) Mood (C) Cognitive symptoms Abdominal pain Headache Fatigue (C) Dizziness Fatigue Pain (C) Bladder symptoms Sleep problem (C) Depression Paresthesias Diarrhea Constipation Sleep problem Muscle weakness Anxiety WPI (C) Muscle tenderness Unrefreshed sleep (C) Cognitive symptoms Somatic symptoms (C) Cognition (C) Muscle pain Mood (C) Fatigue (C) IBS Sleep problem (C) Headache Pain (C) Abdominal pain Constipation Dizziness Paresthesias Muscle weakness Depression Diarrhea Anxiety Fatigue Bladder symptoms Sleep problem −.5 0 .5 1 1.5 Mean decrease accuracy 0 10 20 30 40 50 Mean decrease Gini Figure 52-2 Symptoms that differentiate patients who satisfy American College of Rheumatology 1990 criteria from other rheumatic disease patients with noninflammatory rheumatic pain disorders sorted by strength of association.3 The two figures represent different measures of association. Higher scores mean stronger associations. (C), categorical variable; IBS, irritable bowel syndrome; WPI, Widespread Pain Index. CHAPTER 52 | Fibromyalgia 735 Table 52-1 American College of Rheumatology 2010 Preliminary Diagnostic Criteria for Fibromyalgia3 Criteria A patient satisfies diagnostic criteria for fibromyalgia if the following 3 conditions are met: 1. Widespread Pain Index (WPI) ≥ 7 and Symptom Severity Score ≥ 5 or WPI between 3 and 6 and Symptom Severity Score ≥ 9. 2. Symptoms have been present at a similar level for at least 3 months. 3. The patient does not have a disorder that would otherwise explain the pain. Ascertainment 1. WPI: Note the number areas in which the patient has had pain over the past week. In how many areas has the patient had pain? Score will be between 0 and 19. Shoulder girdle, Lt. Shoulder girdle, Rt. Upper arm, Lt. Upper arm, Rt. Lower arm, Lt. Lower arm, Rt. Hip (buttock, trochanter), Lt. Hip (buttock, trochanter), Rt. Upper leg, Lt. Upper leg, Rt. Lower leg, Lt. Lower leg, Rt. Jaw, Lt. Jaw, Rt. Chest Abdomen Upper back Lower back Neck 2. Symptom Severity Score: Fatigue Waking unrefreshed Cognitive symptoms For the each of the three symptoms above, indicate the level of severity over the past week using the following scale: 0 = No problem 1 = Slight or mild problems; generally mild or intermittent 2 = Moderate; considerable problems; often present and/or at a moderate level 3 = Severe: pervasive, continuous, life-disturbing problems Considering somatic symptoms* in general, indicate whether the patient has: 0 = No symptoms 1 = Few symptoms 2 = A moderate number 3 = A great deal of symptoms The Symptom Severity Score is the sum of the severity of the three symptoms (fatigue, waking unrefreshed, cognitive symptoms) plus the extent (severity) of somatic symptoms in general. The final score is between 0 and 12. *For reference purposes, here is a list of somatic symptoms that might be considered: muscle pain, irritable bowel syndrome, fatigue/tiredness, thinking or remembering problem, 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’s 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. tend to have high levels of other symptoms. As an aggregate concept, polysymptomatic distress cannot be measured directly but can be approximated with the use of surrogate variables. One such surrogate measure of polysymptomatic distress is the fibromyalgia symptom scale—also called the fibromyalgianess scale.12 This scale represents the summation of the Widespread Pain Index (the number of body sites reported as painful) and characteristic fibromyalgia symptoms used in the ACR 2010 preliminary diagnostic criteria.3 In patients with various rheumatic diseases followed in the U.S. National Data Bank for Rheumatic Diseases,13 the upper part of Figure 52-3 shows the relation between the scale and the Short Form-36 (SF-36) Physical Component Summary (PCS) score, the EQ5D Quality of Life score, and the patient’s estimate of global severity. A value of 13 on the fibromyalgianess scale best divides fibromyalgia-positive and fibromyagia-negative patients.14 It can also be seen that the Widespread Pain Index alone is similarly associated with these three measures of illness severity (see Figure 52-3, lower part). About 2% to 4% of the adult population meets criteria for fibromyalgia. One can sense in the figure the distribution of polysymptomatic distress and its correlation with quality of life. Note that polysymptomatic distress is a quantity that exists in all persons, not just in those with fibromyalgia, though it is greater in those with fibromyalgia. The higher the score on the polysymptomatic distress scale and the Widespread Pain Index, the more likely we are to find evidence of social disadvantage such as lower income, less education, and childhood mistreatment, and we will also find more psychologic distress and abnormality; it appears that these factors play a role in the development of fibromyalgia-like symptoms and symptom intensification.14 Fibromyalgianess differs from other measures of polysymptomatic distress by the centrality of musculoskeletal pain because nonarticular musculoskeletal pain is a central component of the scale. To define fibromyalgia by criteria, we must, in effect, draw a line on the distress continuum and say that those beyond this line have fibromyalgia and those before it do not. In the ACR 2010 criteria (see Table 52-1),3 the cut point is identified by the extent of widespread pain and fibromyalgia symptoms. In the 1990 criteria (Table 52-2), the cut point is represented by a combination of tender points and widespread pain. Both cut points, though aided by data analyses, are determined by committees. There is nothing intrinsic in the polysymptomatic distress scale that tells us where the dividing point is. But in the general population a PCS score of 50 represents the population mean, with each standard deviation representing 10 units. At a fibromyalgianess score of 13, patients designated as 50 1 40 .8 30 .6 .4 20 10 1013 20 30 10 Fibromyalgia Severity Scale 45 .9 40 .8 35 .6 25 .5 5 10 15 20 6 4 2 0 30 .7 30 0 1013 8 10 20 Widespread Pain Index 0 5 10 15 20 Widespread Pain Index 1013 20 30 Fibromyalgia Severity Scale Fibromyalgia Severity Scale EQ5D SF-36 Physical Component Summary score Patient global severity DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN Patient global severity | EQ5D PART 6 SF-36 Physical Component Summary score 736 7 6 5 4 3 2 0 5 10 15 20 Widespread Pain Index Figure 52-3 Assessment of polysymptomatic distress. A value of 13 on the Fibromyalgia Severity Scale is the best dividing point between fibromyalgia criteria–positive and fibromyalgia criteria–negative patients. EQ5D, EuroQoL; SF-36, Short Form-36. fibromyalgia have a PCS score about 2 standard deviations below the mean (see Figure 52-3, upper left). Thus fibromyalgia diagnosis identifies persons with substantially reduced quality of life—those at the “extreme end of the spectrum of polysymptomatic distress.”11 Social Construction and Medicalization Many physicians doubt the existence of fibromyalgia as a separate entity, considering instead that it is a primarily a psychologic illness—not a “real disease”11,15-17 (see Figures 52-1 and 52-4). Epidemiologic and clinical studies give no support to the idea that fibromyalgia is a distinct entity18-20; instead, they support the contrary idea that fibromyalgia represents the end of a spectrum of polysymptomatic distress. Illnesses exist within societies, and their existence and phenotype are often a function of the degree of acceptance of the disorder.21 The idea and consequences of fibromyalgia as a socially constructed, medicalized disorder has been discussed at length.2 An illness may be considered to be socially constructed when it is at least in large part the consequence Table 52-2 1990 American College of Rheumatology Criteria for the Classification of Fibromyalgia* 1. History of Widespread Pain Definition: Pain is considered widespread when all of the following are present: pain in the left side of the body, pain in the right side of the body, pain above the waist, and pain below the waist. In addition, axial skeletal pain (cervical spine or anterior chest or thoracic spine or low back) must be present. In this definition, shoulder and buttock pain is considered as pain for each involved side. “Low back” pain is considered lower segment pain. 2. Pain in 11 of 18 Tender Point Sites on Digital Palpation Definition: Pain, on digital palpation, must be present in at least 11 of the following 18 sites: Occiput: bilateral, at the suboccipital muscle insertions. Low cervical: bilateral, at the anterior aspects of the intertransverse spaces at C5-C7. Trapezius: bilateral, at the midpoint of the upper border. Supraspinatus: bilateral, at origins, above the scapula spine near the medial border. Second rib: bilateral, at the second costochondral junctions, just lateral to the junctions on upper surfaces. Lateral epicondyle: bilateral, 2 cm distal to the epicondyles. Gluteal: bilateral, in upper outer quadrants of buttocks in anterior fold of muscle. Greater trochanter: bilateral, posterior to the trochanteric prominence. Knee: bilateral, at the medial fat pad proximal to the joint line. Digital palpation should be performed with an approximate force of 4 kg. For a tender point to be considered “positive,” the subject must state that the palpation was painful. “Tender” is not to be considered “painful.” *For classification purposes, patients will be said to have fibromyalgia if both criteria are satisfied. Widespread pain must have been present for at least 3 months. The presence of a second clinical disorder does not exclude the diagnosis of fibromyalgia. From 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, Arthritis Rheum 33(2):160–172, 1990. CHAPTER 52 Patient perspective | Fibromyalgia 737 Recognition • Not a psychiatric disease • A biologically real disease • Specific biologic cause • Cause is neurobiologic dysfunction Professional organizations Government bodies ACR/EULAR WHO FDA NIH Specific treatments Pharma and Disease Mongering Research Public • Neurobiologic causes • Central sensitization Advertising Physicians Grants to physicians Grants to patient support groups Financial support Research grants to professional organizations Support for professional organization meetings Support for “educational” symposia Recognition Friendly “opinion leaders” Figure 52-4 Nonmedical and societal issues and concerns in fibromyalgia. ACR/EULAR, American College of Rheumatology/European League Against Rheumatism; FDA, U.S. Food and Drug Administration; NIH, National Institutes of Health; WHO, World Health Organization. of societal factors22 that result in “the creation (or construction) of new medical categories with the subsequent expansion of medical jurisdiction.”23 Medicalization is “a process in which nonmedical problems become defined and treated as medical problems, usually in terms of illness and disorders [and are] described using medical language, understood through the adoption of a medical framework, or treated with a medical intervention.”24 Ivan Illich’s 1976 description of medicalization in society set out some markers that are germane to understanding fibromyalgia and opposition to it.25 Illich wrote: “In a morbid society the belief prevails that defined and diagnosed illhealth is infinitely preferable to any other form of negative label or to no label at all” and that “people want to hear the lie that physical illness relieves them of social and political responsibilities.” He called these people “innocent victim[s] of biological mechanisms. … ” In addition, he said diagnosed “ill-health” provides access to disability programs and access to additional health care.25 Data from research about the neurobiologic investigations of pain mechanisms are offered as strong support that persons with fibromyalgia are “innocent victim[s] of biological mechanisms …”26 Given the social construction of fibromyalgia, medicalization is driven primarily by three components (see Figure 52-4). The first is the primary need for patients with fibromyalgia and other FSS for legitimization: Others need to understand that the problem is real and serious, and not primarily a psychosomatic illness.2 The diagnosis of a “valid” fibromyalgia provides entry to medical insurance and treatment and is grounds for work disability and pension. Extensive networks of patient organizations throughout the world work toward this purpose.2 The second pillar of medicalization in fibromyalgia is the pharmaceutical industry.27 Directto-patient advertising is ubiquitous. Often deceptive, it seeks to expand the definition of fibromyalgia, entice persons with pain and fatigue into the diagnosis, and strongly promote its treatments as effective.27 Industry financially supports patient and professional organization, medical education and symposia,2,28 and advertising in professional and lay journals. Virtually all major authors of fibromyalgia studies have received pharmaceutical company support. The influence of drug companies has increased dramatically in the past two decades to the extent that “ … companies are having an increasing impact on the boundaries of the normal and the pathological, becoming active agents of social control.23 Although “medicalization is now more driven by commercial and market interests than by professional claimsmakers,”23 physicians and professional organizations remain the importance sources of scientific support, and National Institutes of Health grants for fibromyalgia research have become common. The more fibromyalgia is seen as a “real disease” with strong criteria, reliable assessments and professional support, 738 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN the more the claims of patients will be taken seriously, the more drugs will be sold and consumed, and the more financial and intellectual support will come to researchers and professional organizations. By contrast, perceiving fibromyalgia as an FSS and part of a continuum with assessments that are not always reliable weakens support for the syndrome and those who have it. The issues that surround fibromyalgia are not scientific ones—it is widely agreed that pain and suffering are real; instead, the issues are social, political, and financial. Historical Development Attempts to characterize and diagnose fibromyalgia have gone through several changes in conceptualization. The earliest roots of the syndrome can be found in the nineteenth century perception of abnormal connective tissue and muscles. In various forms, this concept held sway until the late 1970s when a new emphasis on sleep disturbance and tender points led to proposed clinical criteria that included sleep disturbance and tenderness to palpation at 12 of 14 selected sites.29 In the early 1980s, most of the other fibromyalgia-associated symptoms were identified, and unofficial criteria were proposed that combined symptoms with tenderness.30 With the publication of the ACR criteria in 1990,4 the fibromyalgia case definition was reduced to generalized pain and the presence of multiple tender points. The 1990 criteria, supported by the imprimatur of the ACR, gave the syndrome official sanction. With the criteria publication, professional opposition to fibromyalgia solidified and has continued until the present.2,31-37 In 2010 the ACR preliminary diagnostic criteria3 were published. These criteria expanded the case definition and criteria items to include widespread pain and multiple symptoms including fatigue, disturbed sleep, cognitive symptoms, and multiple somatic symptoms. Despite scientific data questioning the validity of fibromyalgia as a distinct entity, fibromyalgia has become a dominant paradigm, supported strongly by funding and influence of the pharmaceutical industry. At present there are currently several opposing views of fibromyalgia. One view holds that it is not distinct and is a part of FSS,7,9,10 with a functional symptom being defined as one that “after appropriate medical assessment, cannot be explained in terms of a conventionally defined medical disease.”7 The second view, and the dominant paradigm, supports the concept that fibromyalgia is a dis order of “ … aberrant central pain transmission … [in which] purely behavioral or psychologic factors are not primarily responsible for the pain and tenderness … ”38 A third view holds that fibromyalgia is the end of a spectrum of polysymptomatic distress and is not a distinct entity.2,11 Perhaps, not surprisingly, these views are not mutually exclusive. CLINICAL FEATURES Fibromyalgia is characterized by high levels of pain, sleep disturbance, and fatigue combined with a general increase in medical symptoms (Table 52-3) including problems of memory or thinking and often psychologic distress.39 Individuals with the syndrome are unusually sensitive to digital pressure (tender points) in certain body areas. Clinically, fibromyalgia is often identified or suspected by the Table 52-3 Prevalence of Specific Symptoms among 2784 Patients with Fibromyalgia in the National Data Bank for Rheumatic Diseases Symptom Sleep problems Fatigue or tiredness Muscle pain Muscle weakness Paresthesias Cognitive problems Headache Dry mouth Insomnia Easy bruising Dry eyes Depression Blurred vision Irritable bowel syndrome Heartburn Itching Dizziness Constipation Pain/cramps in the abdomen Ringing in ears Pain in upper abdomen Nervousness Nausea Diarrhea Shortness of breath Hearing difficulties Hair loss Oral ulcers Wheezing Loss of appetite Raynaud’s phenomenon Chest pain Rash Sun sensitivity Loss/change of taste Fever Hives/welts Vomiting Seizures % 89.1 88.6 85.2 70.2 67.6 66.3 64.7 53.3 51.8 49.1 47.5 47.5 47.0 46.3 44.4 44.3 42.1 41.9 41.5 41.4 40.3 39.7 37.7 33.6 32.3 29.8 23.6 22.4 21.4 21.1 20.1 19.2 17.1 16.7 14.4 13.4 9.3 9.1 1.7 inexplicability and severity of symptoms and by their number. The most common defining symptom is that of generalized pain (“pain all over”), and pain all over, or widespread pain, is a requirement of the 1990 and 2010 criteria. The clinician may be surprised by the extent and severity of symptoms (see Table 52-3 and Figure 52-3) and surprised at unexpected emotional distress. Fibromyalgia has a quality of inexplicability and unexpectedness. Upper and lower back pain is the most common pain problem (>80%). Many patients, at the clinical interview, emphasize only a few areas of pain. Questions specifically directed to other areas may elicit reports of pain that were not stated spontaneously. Patients with fibromyalgia may complain of greater pain in an osteoarthritic joint than patients without fibromyalgia. Although musculoskeletal pain is central to fibromyalgia, patients may be more concerned about fatigue or memory problems. Fibromyalgia patients perform more poorly in formal cognitive testing than age-matched controls.40 In the National Data Bank for Rheumatic Diseases in 2006, 66% of 2784 fibromyalgia patients complained of memory or thinking problems compared with 31% of 24,479 patients with other rheumatic conditions. The most common symptoms, found CHAPTER 52 in more than two-thirds of patients, are sleep problems, fatigue, muscle pain, paresthesias, and cognitive problems (see Table 52-3). In addition, the prevalence of other important symptoms is as follows: headache, 65%; depression, 48%; and irritable bowel syndrome, 46% (see Table 52-3). A high count of symptoms is characteristic of fibromyalgia and is frequently a key item in the 2010 diagnostic criteria to diagnosis (see Figure 52-2). Fibromyalgia is also associated with increased reporting of comorbid conditions.41,42 The typical picture of fibromyalgia emphasizes certain symptoms (pain, fatigue, sleep disturbance, cognitive problems) and an abundance of symptoms and comorbidities. Given the high levels of symptom variables and membership at the tail of the pain-distress continuum, it is not surprising that evidence of psychosocial disruption and high rates of lifetime psychiatric illness are found.43,44 Fibromyalgia occurs frequently in other rheumatic dis orders including rheumatoid arthritis, osteoarthritis, and systemic lupus erythematosus, in which the prevalence of fibromyalgia exceeds 20%. The clues to identifying fibromyalgia in the presence of other painful disorders are location of pain (nonarticular), continued pain and distress despite objective improvement in the concomitant disorder, and unusual fatigue. ASSESSMENT AND DIAGNOSIS OF A PATIENT WITH FIBROMYALGIA Diagnosis and Diagnostic Criteria A number of approaches to fibromyalgia diagnosis are available. To treat patients, recognition of the degree of pain, fatigue, and other symptoms is necessary, but a specific diagnostic term is not.2,11 Chronic pain syndrome, FSS, or fibromyalgia will all suffice for a diagnostic term in most settings. But in countries such as the United States, chronic pain syndrome or FSS often may not be sufficient for access to insurance reimbursement or pension systems. In addition, direct-to-patient advertising may influence diagnostic terminology and diagnosis toward fibromyalgia. Today, two sets of valid criteria for fibromyalgia are used in most of the world, although country-specific criteria also exist.45 The approach to fibromyalgia diagnosis should differ according to the setting and the physician’s underlying beliefs about fibromyalgia acceptability. The 1990 ACR classification criteria (see Table 52-2)4 require the presence of widespread pain and the identification of pain on palpation at 11 or more of 18 tender points. Until 2010, with the publication of the ACR preliminary diagnostic criteria,3 the 1990 criteria was the only method for an official diagnosis. The 2010 diagnostic criteria are easier in some ways and more difficult in others. They are easier because they eliminate the tender point examination that may be difficult for some examiners. The 2010 criteria are more difficult because they require a thorough symptom evaluation. One advantage of the 2010 criteria is that the examiner/ interviewer becomes much more familiar with the spectrum and degree of the patient’s problem. But for the criteria to work correctly, the interviewer must be comprehensive and thorough. The 2010 criteria provide two scales to evaluate the degree of polysymptomatic distress: the symptom severity scale and the fibromyalgianess scale, both | Fibromyalgia 739 of which are discussed earlier. The fibromyalgianess scale has the advantage that it is a continuous measure of polysymptomatic distress. It is suitable for use in all patients whether or not they satisfy fibromyalgia criteria now or have satisfied them in the past. The scale is also useful when the physician or examiner does not believe in the fibromyalgia concept because it does not require a criteria diagnosis to be useful. The ACR 2010 criteria have been modified by the authors so that self-report forms can be used.14 Although these self-report, form-based criteria can be useful for survey and clinical research, they have not been endorsed by the ACR and they should never be used for clinical diagnosis. Primary, Secondary, and Secondary-Concomitant Fibromyalgia Fibromyalgia is sometimes divided into primary, secondary, and secondary-concomitant fibromyalgia. The term primary fibromyalgia is most often used when there is not another condition with symptoms that could explain fibromyalgia symptoms. This division between primary and secondary fibromyalgia is artificial, however. Back pain in older individuals when age-related radiographic changes are present might be considered secondary fibromyalgia, whereas the same symptoms in younger individuals might be considered primary fibromyalgia. The ACR 1990 criteria study4 showed no difference between primary and secondary fibromyalgia with regard to symptoms and diagnosis. The usefulness of primary fibromyalgia occurs in clinical trials, in which it is desirable to ensure those symptoms are not coming from another well-established illness. A fibromyalgia diagnosis implies understanding of issues such as pain, fatigue, sleep, and cognitive and emotional problems. When fibromyalgia is considered only in patients without other musculoskeletal conditions, the “benefit” of fibromyalgia diagnosis—its consideration of symptom issues and extent of pain—is lost. If fibromyalgia is to be diagnosed or considered, such consideration should be applied to all patients. As noted earlier, fibromyalgia is never a diagnosis of exclusion. When fibromyalgia is diagnosed in the presence of another condition, treatment is indicated for one or both disorders, as determined clinically. Differential Diagnosis The primary symptoms of fibromyalgia, widespread pain and fatigue, can be found in many medical disorders. Similarly, fibromyalgia can coexist with other medical conditions. The proper approach to avoiding misdiagnosis is to ascertain the presence or absence of fibromyalgia and then to determine whether other disorders with widespread pain and fatigue are present. Practically, the categories are fibromyalgia AND other disorders, fibromyalgia AND NOT other disorders, and other disorders AND NOT fibromyalgia. Conditions with fibromyalgia-like features include polymyalgia rheumatica, polymyositis, lupus, cervical spine disorders, hypermobility syndromes, endocrine and paraneoplastic disorders, and forms of polyarthritis including rheumatoid arthritis and ankylosing spondylitis. When differential diagnosis is problematic, it is because the other medical condition is difficult to diagnose or has not been 740 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN evaluated properly. The clue to understanding a patient’s illness is thoroughly evaluating the patient with a careful history, physical examination, and laboratory evaluation. ASSESSMENT OF FIBROMYALGIA SEVERITY Self-Report Measures The ACR 2010 preliminary diagnostic criteria provided a new measure of fibromyalgia severity, the Symptom Severity Score (see Table 52-1).3 Used in the diagnosis of fibromyalgia, this scale also functions as a measure of the severity of fibromyalgia symptoms and can be useful independently of the criteria. Another scale that is an effective measure is the fibromyalgianess scale.14,46 It is the sum of the two items used in the 2010 criteria, the Widespread Pain Index and the Symptom Severity Score. It is suitable for use in all patients, regardless of fibromyalgia status, thereby integrating fibromyalgianess and fibromyalgia symptoms into general patient care. Symptom severity, physical function, and work status are the key status and outcome variables in fibromyalgia, as in other rheumatic disorders. Assessments that can be useful routinely to clinicians include measurements of pain, fatigue, physical function, sleep quality, anxiety, depression, and work status. At minimum, assessments should include visual analog scales (VAS) for pain and fatigue and a measure of functional status. Function can be assessed by one of the family of health assessment questionnaires including the Health Assessment Questionnaire (HAQ),47 the Health Assessment Questionnaire–II (HAQ-II),48 and the Multidimensional Health Assessment Questionnaire (MDHAQ).49 The HAQ is a 33-item questionnaire; the function scale of the HAQ-II and MDHAQ is a 10-item questionnaire. Simple scales for the assessment of anxiety, depression, and sleep disturbance also can be added. For simplicity and ease of administration, however, we recommend VAS assessments of pain and fatigue and either the HAQ-II or MDHAQ. The Fibromyalgia Impact Questionnaire (FIQ) is a widely used 21-item research assessment scale that addresses all of the key fibromyalgia variables and can be used in clinical care.50-52 The limitation of the FIQ is that it is suitable only for use in fibromyalgia patients, whereas the previously mentioned health assessment questionnaires are useful and have been used across the entire range of rheumatic disorders. In addition, the FIQ total scale has no simple interpretation. Functional questionnaire results have reduced validity among fibromyalgia patients. Compared with patients with rheumatoid arthritis and ankylosing spondylitis, there was striking discordance between observed and questionnairereported activities in patients with fibromyalgia.53 This discordance limits slightly the usefulness of functional questionnaires and alters their interpretation: Results may represent perceived rather than actual functional difficulties. Research Questionnaires The Outcome Measures in Rheumatoid Arthritis Clinical Trial committee has recommended research domains and questionnaires for fibromyalgia clinical trials.54 These domains include pain, fatigue, sleep, depression, physical function, quality of life and multidimensional function, patient’s global impression of change, tenderness, dyscognition, anxiety, and stiffness. The recommendations include use of the FIQ and the Medical Outcomes Scale SF-36.55,56 A recent study using observational data has shown that pain, HAQ, and fatigue explained more than 50% of fibromyalgia severity variance57 and that the main determinants of global severity and health-related quality of life in fibromyalgia are pain, function, and fatigue. On the basis of the ACR 2010 preliminary diagnostic criteria, criteria and survey assessments have been developed.14 The Symptom Intensity Scale, which combines the Widespread Pain Index and a VAS fatigue scale, is another self-report measure of fibromyalgia severity that is suitable for clinical and survey research.43 Physical Measures With the exception of the performance of the tender point examination, the physical examination of a patient suspected to have fibromyalgia does not differ from the examination of any other rheumatic disease patient or pain patient. Measurement of pain threshold by the tender point examination is the only routinely useful physical measurement. Although helpful for diagnosis using the ACR 1990 classification criteria (see Table 52-2), the tender point count is poorly correlated with other fibromyalgia symptoms and with change in symptom severity among fibromyalgia patients.58 Patients may improve or worsen substantially without important differences in the tender point count. How to Perform the Tender Point Examination Fibromyalgia patients have a lower threshold for pain than do subjects without fibromyalgia.59 In the clinic, two methods exist by which tenderness can be elicited and measured60—digital palpation and dolorimetry.61 Tender point sites represent specific areas of muscle, tendon, and fat pads that are much more tender to palpation than surrounding sites. Sites selected as part of ACR 1990 criteria4 represent tender point sites that best discriminate between patients with and without fibromyalgia. To test for pain with digital palpation, the ACR 1990 criteria indicate that the examiner should press the tender point site with an approximate force of 4 kg. Usually the second and third fingers or the thumb is used for palpation, and a rolling motion is helpful in eliciting tenderness. The amount of force that the examiner uses is important because a large force would elicit pain in a subject without fibromyalgia, whereas a small force may miss tenderness. The amount of force that does not elicit tenderness in an individual without fibromyalgia (just below the pressure pain threshold) is the correct force to use. In practice, less force is required in smaller, thinner, less-muscled individuals. The pressure used by the examiner and the examiner’s interpretation of the patient’s response can influence results of palpation. The best and most appropriate way to perform the tender point count is to ask the patient if the palpation is painful, accepting only a “yes” as a positive reply, regardless of facial expression or body CHAPTER 52 movement. Specifically, the frequently heard comment of patients to the digital examiner’s question regarding pain, “It’s tender,” is a negative rather than a positive response and should be followed by another question such as, “Yes, but is it painful?” Limitations to the Tender Point Examination Although the tender point examination can provide clinically useful information when properly performed, it can be influenced by external factors. Physicians who believe the patient does or does not have fibromyalgia can influence the results by the amount of pressure applied. The meaning and use of the examination are widely known among physicians, patients, and patient support groups; in some circumstances where a positive or negative examination would seem to be desirable (e.g., in a disability or medicolegal examination), results might differ from those obtained during a routine examination. In addition, the tender point examination is inherently inaccurate around the “diagnostic” tender point count of 11. Epidemiology Most of the information about fibromyalgia is based on sampling using the ACR 1990 criteria. Fibromyalgia is diagnosed more frequently in women (9 : 1 ratio) in clinical studies. However, in population-based studies the femaleto-male ratio is lower. A recent five-country European study noted the female-to-male ratio to be about 1.7 : 1,62 though a U.S. study found a ratio of 6.8 : 163 and the ratio varies from high to low in other countries.62 Using ACR criteria, the prevalence of fibromyalgia in the adult general population is generally similar across the world. The prevalence of fibromyalgia in Wichita, Kansas, was 3.4% among women, 0.5% among men, and 2% overall63; among women in New York City, it was 3.7%.64 In Ontario, Canada, the estimated prevalence was 4.9% among women, 1.6% among men,65 and 3.3% overall. The prevalence of fibromyalgia in these studies increased with age until about age 70, after which it decreased slightly. Outside of North America, reports indicate the prevalence in five European countries was 4.7% and 2.9% according to different screening methods62; in studies in Bangladesh it was 5.3% to 7.5% in women and 0.2% to 1.4% in men66; in North Pakistan, it was 2.1% overall67; in Italy, it was 2.2%68; in Turkey, it was 3.6% for ages 20 to 6469; in Brazil, it was 2.5%70; and in Southwest Sweden, it was 1.3%.71 The prevalence of fibromyalgia in children in three studies was 1.2%,72 1.4%,73 and 6.2%.74 At a follow-up time of 1 year, approximately 25% of individuals meeting ACR criteria initially still satisfied the criteria.73,74 These data should not be interpreted as evidence of prognosis because some individuals not meeting criteria initially meet them at the 1-year follow-up. Instead, the data suggest that the concept of fibromyalgia in children may be dubious, particularly when dependent on tender point assessment. The prevalence of fibromyalgia is generally greater in clinical settings than in epidemiologic studies. It was noted to be 5.7% in general medical clinics75 and 2.1% in family practice settings.76 In rheumatology clinics, fibromyalgia | Fibromyalgia 741 prevalence was expectedly higher: 12%77 to 20%30 of new patients. The ACR 2010 criteria should result in changes in the sex ratio because men have higher pain thresholds and are therefore less likely to be diagnosed as having fibromyalgia than women when the 1990 criteria are used. The proportion of men with fibromyalgia in the community in a large German population study was 40.3%.78 This study included criteria79 that used the Regional Pain Scale80 and measurement of fatigue. Diagnosis by this method yields results that are similar to survey modifications on the ACR 2010 preliminary criteria.14 The overall prevalence in the German study was 3.8%.78 Additional studies are necessary to determine the prevalence of fibromyalgia when the 2010 criteria are used. ETIOLOGY AND PATHOPHYSIOLOGY In the 30-year period following the establishment of the fibromyalgia case definition and criteria, there have been substantial advances in understanding mechanisms associated with fibromyalgia pain and other symptoms.81 Although most of the recent study data are robust, the interpretation of the data is often questionable and misleading. Because these research data form the basis of “scientific” support for fibromyalgia, the objections should be considered carefully and seriously. We outline some of the objection before providing the research data themselves. 1. Research data treat fibromyalgia as a disease associated with at least 11 tender points (ACR 1990 criteria definition), but it is exceedingly unlikely that the observed pathophysiologic abnormalities are confined to greater than or equal to 11 tender points because the body of clinical and epidemiologic evidence does not support a dichotomous condition. It seems likely that observed abnormalities are also found in nonfibromyalgia patients. Studies need to be performed to determine the distribution of the observed abnormalities in pain patients not satisfying the fibromyalgia classification criteria definition. 2.Almost all of the data linking the observed abnormalities to fibromyalgia are correlational, but they are often interpreted causally—a direction of causality that may be wrong. The causal path in fibromyalgia may be complex. All human processes and sensations are expressed biologically. It would be surprising not to find associations. 3.Even assuming causal associations, the explanatory power of these associations have not been described and may be weak. The noted associations do not necessarily predict development of fibromyalgia. 4.The pathogenetic associations attributed to fibromyalgia are noted in other disorders.82,83 5.The literature of fibromyalgia pathogenesis is filled with inadequate proofs because authors have drawn strong conclusions from limited correlative data. 6.Selection of patients and controls can be a problem. Specifically, patients may be too “good” and control subjects represent “healthy controls” rather than other pain patients. Healthy controls will always be different from patients with illnesses. 742 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN Muscles and Microtrauma Originally thought to be important in pathogenesis, muscle and tendon disorders have fallen out of favor because they do not explain adequately the systemic symptoms of fibromyalgia. In addition, changes found in muscle biopsy specimens are nonspecific, consistent with many types of muscle damage, ranging from ischemia to simple deconditioning, and are not different from changes found in individuals without fibromyalgia. Genetic and Familial Factors Compared with patients with rheumatoid arthritis, fibromyalgia aggregated strongly in families: the odds ratio measuring the odds of fibromyalgia in a relative of a proband with fibromyalgia versus the odds of fibromyalgia in a relative of a proband with rheumatoid arthritis was 8.5.84 Genetic factors may predispose individuals to fibromyalgia.81 Patients with chronic widespread pain and fibromyalgia have been found to have low gene expression for the proinflammatory cytokines interleukin-4 and interleukin-10 and reduced levels of serum concentrations compared with controls. These findings might indicate a role for cytokines in the pathophysiology of fibromyalgia or as a sequel of chronic pain and its treatment.85 However, a study of 31,318 twins in the Swedish Twin Registry suggested that the co-occurrence of FSS in women can be best explained by affective and sensory components in common to all these syndromes, as well as by unique influences specific to each of them, suggesting a complex view of the multifactorial pathogenesis of these illnesses.83 Psychosocial Factors Psychosocial factors, which include reduced education, nonmarried status, lower household income, smoking, and obesity, have been identified in many studies. The chicken or egg question remains.82 There has been disagreement as to whether psychiatric abnormalities represent reactions to chronic pain or whether the symptoms of fibromyalgia are a reflection of psychiatric disturbance. Psychiatric disorders may interact with the neuroendocrine system as part of a stress reaction.44 The most common psychiatric conditions observed in patients with fibromyalgia include depression, dysthymia, panic disorder, and simple phobia.86 In the National Data Bank for Rheumatic Diseases 64% of patients report prior depression, and 8% report mental illness. Fibromyalgia also occurs in patients without significant psychiatric problems, however. Some individuals with fibromyalgia satisfy the American Psychiatric Association criteria for somatoform disorders (DSM 307.80 and 307.89).87 Sleep Disturbance Fibromyalgia patients often report unrefreshing and nonrestorative sleep.88 Electroencephalographic abnormalities initially were thought to play a major role in the pathogenesis of fibromyalgia, but it is now clear that such abnormalities are nonspecific findings. Sleep electroencephalographic studies show abnormalities of delta wave or stage 4 sleep by repeated alpha wave intrusion. Similar abnormalities are found in healthy individuals and in individuals with emotional stress, fever, osteoarthritis, rheumatoid arthritis, and Sjögren’s syndrome. Stress-Related Neuroendocrine Dysfunction Stress responses and endocrine axes are disturbed in fibromyalgia, but many of these changes are commonly seen in patients who have known external sources of chronic pain. It is unclear whether these endocrine disturbances in fibromyalgia are primary to the disorder or are secondary to the pain or distress associated with fibromyalgia. Patients with fibromyalgia report more past stressful life events and more daily stressful hassles than patients with rheumatoid arthritis or pain-free healthy controls. Similarly, fibromyalgia is associated with increased reports of virus and other infections (Epstein-Barr virus, parvovirus, Lyme disease); hormonal alterations such as hypothyroidism; and catastrophic events where the patient is the victim of actions of others (e.g., war, car accidents) but not natural disaster58 preceding fibromyalgia; and a higher frequency of sexual abuse in childhood. Work-related psychologic factors such as work demands and factors such as job control, social support, and psychologic distress are associated with reporting of musculoskeletal pain, particularly when pain is reported at multiple sites.89 Primary Neuroendocrine Dysregulation Primary neuroendocrine dysregulation found in fibro myalgia can be divided into changes in the two major stress systems: the hypothalamic-pituitary-adrenal axis and the autonomous nervous system. In fibromyalgia, almost all hormonal feedback mechanisms controlled by the hypothalamus are disrupted. After stimulation of the hypothalamic-pituitary-adrenal axis with exogenous corticotropin-releasing hormone or by insulin-induced hypoglycemia, an exaggerated pituitary adrenocorticotropic hormone release has been observed with relative adrenal hyporesponsiveness.90 Serum thyroid hormone levels are normal, but after intravenous injection of thyrotropin-releasing hormone, patients with primary fibromyalgia responded with a significantly reduced secretion of thyrotropin and thyroid hormones.91 Growth hormone is secreted during stage 4 sleep and is important for muscle repair and strength. Low levels might explain extended periods of muscle pain after exertion in fibromyalgia patients. Serum growth hormone levels and levels of somatomedin C (insulin-like growth factor-I) have often been reported to be low, but results are inconsistent.92 It is possible that physical deconditioning, related to avoidance of physical activities because of pain, could lead to more fatigue, stiffness, and, via altered growth hormone metabolism, sleep disturbance. Autonomous Nervous System Sympathetic function in fibromyalgia patients has been reported as low, normal, or functionally high. There is a derangement of sympathetic tone and reaction in some patients, being high or low, depending on the situation. One CHAPTER 52 explanation for this finding may be that most studies did not control for physical activity levels of participants.93 It has also been suggested that fibromyalgia is a generalized form of complex regional pain syndromes such as reflex sympathetic dystrophy.94 Abnormal Pain Processing There are major differences between the sexes with respect to analgesic responses, across all animal species. This may explain the decreased pain tolerance in women with fibromyalgia compared with men. Patients with fibromyalgia have reduced pain tolerance to stimuli that are normally not painful such as pressure, heat, and electric pulse, at the classic tender points and control points (allodynia). They also perceive pain as being more intense and extending for a longer time (hyperalgesia). This abnormal sensory pain processing could be explained by increased pain facilitation and reduced pain-inhibiting mechanisms on the spinal and cerebral levels. Fibromyalgia patients also displayed abnormal temporal summation of pain after a series of thermal stimulations, called “wind-up.”95 The concentration of substance P, a neuromodulator of pain, in the cerebrospinal fluid was threefold greater in fibromyalgia patients than in controls. Substance P may play a role in spreading of muscle pain. This elevation of substance P is not specific to fibromyalgia, however, and has been shown in patients with pain due to other causes. Measures of pain intensity in fibromyalgia patients are correlated with levels of metabolites of the excitatory amino acid neurotransmitters glutamate and aspartate. Sensitization of nociceptive neurons in the spinal dorsal horn by hyperexcitable receptors such as the glutamate receptor N-methyl-daspartate could be one of the mechanisms responsible for pain in fibromyalgia.96 Decreased Pain Inhibition Pain inhibitory pathways, descending from the cortex, limbic system, hypothalamus, thalamus, and brain stem, modulate the activity of spinal nociceptive neurons. In fibromyalgia patients, regional blood flow seems to be reduced in the most important pain processing areas in the brain, the thalamus and caudatum, compared with controls.97 Serotonin is a neurotransmitter in the descending inhibitory pathways that inhibits release of substance P and excitatory amino acids from the terminals of primary afferent neurons. Serotonin also regulates nonrapid eye movement sleep. Low levels of serotonin metabolites have been reported in the cerebrospinal fluid and serum of patients with fibromyalgia and low back pain.96 Serotonin antibodies are found in fibromyalgia patients four times as frequently as in controls. Although serotonin antibodies have no diagnostic relevance, they could potentially play a role in pathogenesis.98 The role of serotonin in the pathophysiology of fibromyalgia is unclear. Drugs that affect serotonin metabolism or action do not have a dramatic effect. Concentrations of enkephalins in the cerebrospinal fluid are roughly twice as high in fibromyalgia and idiopathic low back pain patients, consistent (but not pathognomonic) with the hypothesis that there is increased release of endogenous mu opioid ligands in fibromyalgia, leading to | Fibromyalgia 743 high baseline occupancy of the receptors. This is consistent with the anecdotal clinical experience that opioids are generally ineffective analgesics in patients with fibromyalgia.58 CENTRAL NERVOUS SYSTEM (CNS) INVOLVEMENT IN FIBROMYALGIA SYNDROME Proton Magnetic Resonance Spectroscopy and Functional Brain Imaging in Assessment of CNS Involvement in Fibromyalgia Why Search in the Brain For an Explanation of the Riddle of Fibromyalgia? Fibromyalgia is complex and variably expressed but almost always features some degree of pain amplification. Interestingly, this hyperalgesia is not confined to pressure stimuli but also involves heightened responses to heat, noise, and smell, suggesting an important role for central pain processing abnormalities.99 Although the pathology of fibromyalgia is poorly understood, a growing body of evidence suggests involvement of the CNS. The hippocampus is a brain center that is sensitive to the effects of stress exposure and has been demonstrated to be affected in a variety of disorders that, like fibromyalgia, began with a stressful experience.100 Ultimately, there is central sensitization to pain in which low-intensity stimuli in peripheral tissues such as skin and muscle generate an exaggerated nociceptive response that is interpreted centrally as pain. The central mechanisms underlying this amplified pain perception have been explored using a number of advanced imaging techniques that aim to localize and characterize abnormalities in specific areas of the brain called the pain “matrix.”101 ADVANCED IMAGING TECHNIQUES Studies with single photon emission computed tomography, using injected radioactive compounds in the bloodstream that decay over time, have reported an abnormal reduction of regional cerebral blood flow in thalamic and caudate nuclei of patients with fibromyalgia during rest.97,102 In two other studies that used functional magnetic resonance imaging, fibromyalgia patients exhibited enhanced responses to painful and nonpainful stimulation in multiple areas of the brain such as the somatosensory cortices, insula, putamen, anterior cingulate cortex, and cerebellum, as compared with healthy control subjects.103,104 These findings were consistent with a left shift in the stimulus-response function, which is characteristic of centrally mediated hyperalgesia and reduced noxious threshold to sensory stimuli.81 Hippocampus Dysfunction in Fibromyalgia and Neurometabolic Assessment by Proton Magnetic Resonance Spectroscopy The hippocampus plays crucial roles in maintenance of cognitive functions, sleep regulation, and pain perception, and in studies using single-voxel magnetic resonance 744 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN spectroscopy, metabolic dysfunction of the hippocampus was found in fibromyalgia patients.105,106 Others found proton magnetic resonance spectroscopy abnormalities at the basal ganglia and the supraventricular white matter and right dorsolateral prefrontal cortex.107 Gray matter loss in fibromyalgia patients was suggested by magnetic resonance voxel-based morphometric analysis.108 In this study fibromyalgia patients had significantly less total gray matter volume and showed a 3.3 times greater age-associated decrease in gray matter than healthy controls. The longer the individuals had had fibromyalgia, the greater the gray matter loss, with each year of fibromyalgia being equivalent to 9.5 times the loss in normal aging. In addition, fibromyalgia patients demonstrated significantly less gray matter density than healthy controls in several brain regions including the cingulate, insular, and medial frontal cortices and parahippocampal gyri.108 In particular, fibromyalgia appears to be associated with an acceleration of age-related changes in the very substance of the brain. Moreover, the regions in which objective changes are demonstrated may be functionally linked to core features of the disorder including affective disturbances and chronic widespread pain. Sensory Gating and Reduced Brain Habituation to Somatosensory Stimulation in Patients with Fibromyalgia The attenuation effect of the event-related brain responses following stimulus repetition in healthy subjects is a wellknown psychophysiologic phenomenon called sensory gating.109,110 Montoya and colleagues examined brain activity elicited by repetitive nonpainful stimulation in patients with fibromyalgia in order to determine possible psychophysiologic abnormalities in their ability to inhibit irrelevant sensory information. Their findings suggest that in fibromyalgia patients, there is abnormal information processing, which may be characterized by a lack of inhibitory control to repetitive nonpainful somatosensory information during stimulus coding and cognitive evaluation. These data further extend previous findings111-113 of an abnormal brain processing of nonpainful somatosensory information, rather than a generalized information processing dysfunction, in patients with fibromyalgia.110 Deficits of Nociceptive Information Processing In this regard, findings of Montoya and colleagues114 add to a growing literature in which fibromyalgia patients have been shown to have some deficits of nociceptive information processing relative to healthy controls such as enhanced sensitivity to repetitive pain pressure, abnormal maintenance of pain sensations after repetitive thermal stimulation,115,116 or deficits in the endogenous pain inhibitory system,117 In another work Wood and colleagues118 investigated presynaptic dopaminergic function in six female fibromyalgia patients in comparison with eight age- and sex-matched controls as assessed by positron emission tomography (PET) with 6-fluoro-l-DOPA as a tracer. Their findings indicate a disruption of presynaptic dopamine activity wherein dopamine plays a putative role in natural analgesia. Harris and colleagues119 demonstrated by PET decreased mu opioid receptor availability in fibromyalgia. Further, it has been suggested that hyperalgesia and allodynia in fibromyalgia, as well as in other chronic pain states, are the behavioral consequences of central sensitization. Thus it would be possible that the observed disruption of the inhibitory brain mechanism involved in the early processing of non-nociceptive repetitive stimulation might be a further consequence of those neuroplastic changes due to central sensitization associated with chronic pain.110 These findings indicate that central factors are important in the processing of pain in people with fibromyalgia. The neuroimaging findings are highly consistent with studies done in pain more generally.120 These findings suggest that individuals with fibromyalgia have a narrow range of tolerance for pain and perhaps other sensory stimuli, before it becomes noxious.58 MANAGEMENT OF FIBROMYALGIA: RESEARCH STUDIES AND RECOMMENDATIONS The value of contemporary treatment can be gauged by review of outcome studies. Fibromyalgia outcome has been the subject of a number of reports, usually in small studies encompassing short periods of time. In general, results of these studies tend to suggest little change in symptoms, suggesting a limited effect of treatment. Most long-term observational studies do not show improvement in fibromyalgia symptoms and outcomes, even when patients are followed in centers with special interest and knowledge of fibromyalgia.121,122 In a recent longitudinal study, 1555 patients displayed continuous high levels of self-reported symptoms and distress despite treatment over a mean of 4 years of follow-up. Service utilization (a measure of symptom activity) does not lessen after diagnosis.123 Benefit of treatment is generally not sustained in long-term randomized clinical trials.124,125 These data should be kept in mind when evaluating the results of treatment clinical trials. The null hypothesis for a chronic, painful disorder should not be no short-term treatment effect, but instead no longterm treatment effect. Short-term studies should be regarded with suspicion, and most fibromyalgia studies are short term. Compliance with treatment is an important problem in fibromyalgia, and in fibromyalgia clinical trials the dropout rate is high. Even when intention-to-treat analyses are performed, the effectiveness of treatment is overestimated. Patients who follow exercise recommendations have better outcomes than patients who do not; however, most patients in clinical practice do not or will not perform aerobic exercises. It is fair to conclude that exercise prescription is often an ineffective recommendation, rather than concluding that it is an effective treatment. Treatment trials without a true, contemporaneous control group cannot provide meaningful estimates of efficacy because they often exaggerate efficacy. In evaluating study results, the degree of improvement must be examined and the degree of improvement must be clinically meaningful. Even when improvement is clinically meaningful, the CHAPTER 52 baseline and final outcome values such as values of pain and fatigue must be considered. If the patients are selected for trials in relative (temporary) flare conditions, they may improve “significantly” but still have high levels of the outcome variables at the conclusion of the trial. Numerous useful reviews of the short-term treatment in fibromyalgia are available.126-134 Most such reviews rely on the concept of efficacy and rank evidence as a function of study quality. One review indicates that “evidence for treatment efficacy was ranked as strong (positive results from a meta-analysis or consistently positive results from more than one randomized controlled trial [RCT]), moderate (positive results from one RCT or largely positive results from multiple RCTs or consistently positive results from multiple non-RCT studies), and weak (positive results from descriptive and case studies, inconsistent results from RCTs, or both).”126 As noted by these authors, studies are necessary “… to determine whether the improvement is maintained over months or years.” Recent meta-analyses have included measurements of standardized mean differences (effect sizes)127-134 but still do not assess long-term benefit. Still another problem with the interpretation of fibromyalgia studies relates to study scales. Because patients diagnosed as having fibromyalgia have problems with pain, fatigue, cognition, and anxiety and depression, to name some issues in fibromyalgia, studies may select different scales and outcomes according to the interests of the investigators. This leads to problems in comparing study results. In addition, when multiple outcomes and study instruments are selected, frequently studies can show positive results for one outcome and negative results for another. Even when an outcome such as pain is being measured, if there is more than one pain scale, positive results may be found with one pain scale and not with another. Complex scales are also difficult to interpret, as is the case with the commonly used FIQ total scale. This composite summary scale has no simple interpretation: A reader may note an improvement but not have a clear idea of what such improvement means. From 6750 fibromyalgia patients screened in the National Data Bank for Rheumatic Diseases, the mean (standard deviation) VAS pain and fatigue scores were 6.3 (2.5) and 7.0 (2.5). As an aid in interpreting effect sizes, the following data are presented; assuming a baseline score of 7.0 on a 0 to 10 VAS scale, the following are the effect size, change score, post-treatment score, and percent improvement at the last assessment: 0.3, 0.75, 6.25, 10.7%; 0.4, 1.25, 6.0, 14.3%; 0.5, 1.25, 5.75, 17.9%; 0.6, 1.5, 5.5, 21.4%. Finally, the main limitations of results and inferences from fibromyalgia clinical trials is that they cannot be extrapolated to patients in practice because of the artificial nature of clinical trials, issues of compliance, and absence of long-term results. Häuser and colleagues135 have provided a detailed compendium of the full range of fibromyalgia therapy, citing research evidence and committee recommendations. In making recommendations for therapy, these reviewers also considered costs and adverse effects. Readers should find this review particularly helpful, although they should keep in mind the degree of observed benefit, its persistence, and other issues mentioned earlier. | Fibromyalgia 745 Diagnosis Diagnosis may be an important aspect of treatment. Diagnosing fibromyalgia in individuals with short-term stressrelated illnesses is harmful and leads to prolonged illness and medicalization. No valid evidence supports the assertion that diagnosis of fibromyalgia in patients with longterm symptoms has a salutary effect. A study of primary care patients in the United Kingdom reported that “ … patients who had been diagnosed as having [fibromyalgia] reported higher rates of illness and health care resource use for at least 10 years prior to their diagnosis, which suggests that illness behavior may play a role. … Diagnosis has a limited impact on health care resource use in the longer term, possibly because there is little effective treatment.”136 At the patient level, there is no evidence that diagnosis is harmful. Using the diagnostic term in the presence of severe symptoms often makes it easier for physicians and patients to discuss the condition; when fibromyalgia is not diagnosed, patients sometimes ask directly, “Do I have fibromyalgia?” In considering making the diagnosis of fibromyalgia, the physician should consider the following comment by Barsky and Borus6: “The hyperbole, litigation, compensation, and self-interested advocacy surrounding the FSS can exacerbate and perpetuate symptoms, heighten fears and concerns, prolong disability, and reinforce the sick role. Excessive medical testing and treatment expose patients to iatrogenic harm and amplify symptoms.” But if fibromyalgia is “diagnosed,” it is important to be clear to the patient that fibromyalgia is a name given to the symptoms, not a cause of the symptoms. When a fibromyalgia diagnosis is applied to the larger community, rather than at the level of the individual patient, it has been suggested that a virulent idea and a maladaptive social construction of disease such as fibromyalgia can induce and sustain illness in susceptible persons: a psychosomatic meme, acting as a transmissible template.137 Direct-to-patient advertising and disease mongering by drug companies expand the definition of fibromyalgia and recruit patients to the diagnosis, offering support to this idea. Education Education in some reports may have a modest effect on fibromyalgia symptoms such as fatigue, anxiety, and depression but has limited to no effect on pain.138,139 What is called education is actually composed of two components— education and rapport or engagement—and it is impossible to distinguish the two components. Most education studies are derived from formal university-based treatment programs; only one study was applicable to clinical practice,139 and the sample size was too small to evaluate the effect of the intervention in fibromyalgia. All studies had deficiencies in the validity of the control groups; there are no longterm data on the effect of education. Although it is sensible that education should always be part of any treatment program and is part of establishing rapport, its content should depend on the patient, the duration of illness, and the diagnostic label already present. The goal of education is to help the patient understand and manage his or her 746 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN symptoms optimally, reduce dependence on the medical system, and work effectively within that system when necessary. There are no data, however, as to whether, within the clinical setting, extensive education is more or less effective than limited education. In a group of 100 consecutive enrollees in a 1.5-day multidisciplinary group outpatient fibromyalgia treatment program, after 30 days a 12.8% improvement was noted in the 78 who completed the study.140 Exercise Aerobic exercise increases cardiovascular fitness and reduces pain and other fibromyalgia symptoms. In a short-term RCT, exercise improved aerobic performance by 16% and pain by 13%.141 A carefully done, well-powered RCT of a 12-week community-based exercise program compared with relaxation controls showed a 4% difference in FIQ scores at 1 year but nonsignificant changes in McGill pain scores and SF-36 scores.142 At the 12-month follow-up, 38% of subjects in the exercise arm and 22% in the control arm rated themselves much better or very much better. Only 53% of patients attended more than half of the intervention sessions. A follow-up report at 12 months on patients who participated in a 23-week, three-times-per-week exercise program indicated general improvement compared with baseline values.143 The degree of improvement as measured by the FIQ was 5%. The Cochrane collaboration evaluated 34 studies that included exercise, noting that there is moderate-quality evidence that aerobic-only exercise training at recommended intensity levels has positive effects on global well-being (standard mean difference [SMD], 0.49) and physical function (SMD, 0.66) and possibly on pain. The researchers concluded that “supervised aerobic exercise training has beneficial effects on physical capacity and fibromyalgia symptoms.”144 A noncontrolled study comparing waterbased exercise with land-based exercise showed an average 36% reduction in pain.145 Exclusions in this study included 67 for work schedule incompatibility and 32 for nonspecified refusals; 60 patients were randomly assigned, and 52 completed the study. Practically, the problem with exercise prescription is that it is difficult to get fibromyalgia patients to participate. Exercise may produce “short-term increases in pain and fatigue that should abate within the first few weeks of exercising,”146 but this may be unacceptable to patients in ordinary clinical settings. Even in formal programs, adherence to exercise is poor.147,148 In a 4.5-year follow-up of a randomized trial of exercise, only 20% of patients maintained an adequate physical activity level.149 In the National Data Bank for Rheumatic Diseases from 1999 to 2010, 16% of 3115 fibromyalgia patients reported performing some aerobic exercise weekly, but only 5% performed at levels substantial enough to result in increasing or maintaining aerobic fitness. Pharmacotherapy Analgesics and Nonsteroidal Anti-inflammatory Drugs Many drugs frequently used by patients diagnosed as having fibromyalgia have not been formally evaluated for efficacy or effectiveness.126 With respect to analgesics and non steroidal anti-inflammatory drugs (NSAIDs), a 1998 multicenter study of 538 fibromyalgia patients noted the following usage in a 6-month period: aspirin, 20.6%; NSAIDs, 55.9%; acetaminophen, 27.6%; strong opioid analgesics, 6.4%; and nonopioid analgesics, 21.5%.160 Tramadol use was 15%. Tramadol use remained at 15% in 2010 in the National Data Bank for Rheumatic Diseases. These data, showing the substantial use of NSAIDs, are important because it is often suggested that NSAIDs are ineffective.126 A few analgesic and NSAID treatments have been formally evaluated. Naproxen, 500 mg twice daily (n = approximately 15), which is the only NSAID that has been studied, was indistinguishable from placebo (n = approximately 15) in a controlled clinical trial of relatively young subjects (age 48 years).161 The combination of tramadol and acetaminophen reduced pain 18.5% more than did the use of placebo.162 In this trial, 48% in the active treatment group and 62% of placebo users were noncompleters in this 3-month trial. Psychotropic Agents Many drugs that have antidepressant and other psychotropic attributes have been used in fibromyalgia treatment. Such drugs reduce pain centrally, even in the absence of depression, and may be employed at doses that are insufficient to treat depression. Because of the many different trials and classes of drugs studied, meta-analyses have provided a useful overall overview.129,163,164 We summarize the results of Häuser and colleagues.129 In their meta-analysis of 18 RCTs (1427 participants), there was strong evidence for an association of antidepressants with reduction in pain (SMD, 0.43); fatigue (SMD, 0.13); depressed mood (SMD, .26); and sleep disturbances (SMD, 0.32). The major classes of drugs included tricyclic and tetracyclic antidepressants (TCAs): amitriptyline and nortriptyline; selective serotonin reuptake inhibitors (SSRIs): paroxetine, fluoxetine, and citalopram; serotonin and noradrenaline reuptake inhibitors (SNRIs): duloxetine, milnacipran; and monoamine oxidase inhibitors (MAOIs): moclobemide and pirlindole. In subanalysis by class, effect sizes for pain reduction were large for TCAs (SMD, 1.64); medium for MAOIs (SMD, 0.54); and small for SSRIs (SMD, 0.39) and SNRIs (SMD, 0.36). Similar, although slightly weaker, results are noted with cyclobenzaprine. Compared with clinical trial results, results in longitudinal studies and clinical practice show marginal effectiveness of tricyclic antidepressants and similar treatments. A highquality RCT found no difference in the response to amitriptyline and cyclobenzaprine.165 Cognitive Behavioral Therapy Cognitive behavioral therapy is a form of short-term, goaloriented psychotherapy. It has been the subject of some positive reports,150-154 some less positive reports,124,155,156 and some completely negative studies.157-159 Other Pharmacologic Treatments On the basis of clinical trial criterion for efficacy, there is no evidence for efficacy of NSAIDs, corticosteroids, benzodiazepine and nonbenzodiazepene hypnotics, guaifenesin, CHAPTER 52 melatonin, calcitonin, opioids, thyroid hormone, dehydroepiandrosterone and magnesium, or anti–tumor necrosis factor therapy.126 Nonpharmacologic Treatments There is some evidence for efficacy of numerous nonmainstream treatments including strength training127,149,166 and hypnosis.167 There is weak evidence for chiropractic, manual, and massage therapy and no evidence of efficacy for tender or trigger point injections or flexibility exercise. Evidence for acupuncture is contradictory,168,169 as is evidence for the efficacy of biofeedback170-172 and balneotherapy.173-175 Local injections in muscular areas of pain are also commonly employed by rheumatologists. The authors surveyed rheumatologists regarding the use of injections and found them to be used frequently, in agreement with others.126 Rheumatologists reported that patients “like injections,” but also that the rheumatologists did not know what else to do. A comprehensive review of nonpharmacologic therapies is available.176 Combination Therapy Although most studies reported earlier concern monotherapy, in practice most fibromyalgia treatments combine multiple therapies. Ordinarily these treatment regimens use analgesics, antidepressants, education, and exercise (at least, exercise recommendations). The extent to which several or many therapies is superior to one or few therapies is not clear. But the effect seems small. So one cannot simply add effect sizes of individual therapies to gauge the multitherapy effect. A meta-analysis of multicomponent treatment in RCTs (at least one educational or other psychologic therapy with at least one exercise therapy) included nine RCTs with 1119 patients.128 The authors reported: “There was strong evidence that multicomponent treatment reduces pain (SMD, 0.37;); fatigue (WMD, 0.85); depressive symptoms (SMD, 0.67); and limitations to health-related quality of life (HRQOL) (SMD, 0.59) and improves self-efficacy pain (SMD, 0.54) and physical fitness (SMD, 0.30) at posttreatment. There was no evidence of its efficacy on pain, fatigue, sleep disturbances, depressive symptoms, HRQOL, or self-efficacy pain in the long term. There was strong evidence that positive effects on physical fitness (SMD, 0.30) can be maintained in the long term (median follow-up 7 months).” Overall, these data indicated increased benefits of multicomponent treatment as defined here, compared with “other” therapies. But the benefit is still modest and cannot be clearly extrapolated to the long term. Practical Recommendations in the Approach to a Patient with Fibromyalgia The goal of fibromyalgia treatment is to improve the physical and mental health of patients and their quality of life. This goal implies helping patients manage distressing symptoms, but with decreased dependence on the medical care system. There are no studies as to how often the simple recommendations of education, exercise, and limited pharmacologic treatment provide results at an acceptable level | Fibromyalgia 747 of symptoms and functional ability. Data from the National Data Bank for Rheumatic Diseases show, however, that 61% of 3276 fibromyalgia patients observed from 1998 to 2010 were somewhat or very dissatisfied with their health compared with 35% of 24,891 patients with rheumatoid arthritis. These data indicate that contemporary treatment of fibromyalgia is generally unsatisfactory. This high level of dissatisfaction is reflected in physician and patient interactions. An unknown but probably small proportion of rheumatology experts refuse to accept referral of fibromyalgia patients. A larger proportion is unhappy seeing such patients or is uncomfortable providing care. Patients, sensing this attitude, are equally unhappy with physicians: Patient support groups provide specific advice on finding positive, sympathetic physicians including identifying them by name. Physician behavior results from a general uncomfortableness with illnesses that are often unresponsive to treatment and have strong psychologic and psychosocial components. There is no simple resolution to this problem. Physicians who are unable to provide helpful care to patients with fibromyalgia should make that known to the patients. Interest in fibromyalgia and drug company support has resulted in extensive studies of treatment,127 often with recommendations for treatment.127 The practical result of applying recommendations based on short-term clinical trials to an often poorly responsive chronic illness is uncertain because there is as yet no evidence of long-term effectiveness of treatment. In the face of ineffectiveness, treatment recommendations can lead to switching from one therapy to the next and increased medicalization. In considering fibromyalgia treatment, physicians should determine what resources are available in the community, and whether the resources are effective and helpful. The educational, exercise, and cognitive behavioral therapy programs described in the research studies earlier are often not available to U.S. community physicians. Available programs may or may not be competent, appropriate, or helpful. Pain management programs sometimes mean little more than spinal blocks and “trigger point” injections, and physical therapy referral often results in treatments that are ineffective for fibromyalgia. The referring physicians should investigate the quality and outcomes of referral resources. Although the common recommendations of education, exercise, and pharmacotherapy are often appropriate, particularly in newly diagnosed cases, patients with established fibromyalgia have often experienced these recommendations and treatments. Whether such treatments have strong evidence for effectiveness or not, as measured by clinical trials, they are often not clinically effective enough, and patients return to the physician for additional suggestions and care. The European League Against Rheumatism (EULAR) task force points out, on the basis of limited evidence127 and consensus recommendation, that full understanding of fibromyalgia requires comprehensive assessment of pain, function, and psychosocial context. Fibromyalgia should be recognized as a complex and heterogeneous condition where there is abnormal pain processing and other secondary features. Optimal treatment requires a multidisciplinary approach with a combination of nonpharmacologic and pharmacologic treatment modalities tailored according to 748 PART 6 | DIFFERENTIAL DIAGNOSIS OF REGIONAL AND DIFFUSE MUSCULOSKELETAL PAIN pain intensity; function; and associated features such as depression, fatigue, and sleep disturbance in discussion with the patient. The question arises as to how to approach a resistant patient with fibromyalgia, given the knowledge that after failure with several standard treatments, success with other medications is unlikely. Should the physician simply go from one (dubious) treatment to another? Should the physician use treatments of dubious or uncertain value? The adverse effects of inappropriate or unnecessary treatments are not inconsequential and include dependence, medicalization of common symptoms, overuse of medical care, increased costs, and side effects. One point of importance is that the physician should at least measure pain using a VAS scale. A similar simple measure is available for fatigue. One really cannot know how the patient is doing without such measurements. The physician must be friendly and interested—a resource the patient can rely on. Testing should be limited and reserved for times when it is truly necessary to investigate comorbid conditions. Comorbid conditions such as arthritis and obesity should be treated because they can contribute to increasing physical and mental symptoms. The worst problem should be identified. Sometimes identifying where the pain problem began can offer clues to appropriate treatment of the coexisting condition. If many fibromyalgia treatments have been tried and have been unsuccessful, it is generally not a good idea to try even more similar, and soon to be unsuccessful, therapies. We often ask patients, “Which treatment has been most helpful?” and suggest (assuming treatment is necessary and helped at all) that they return to that treatment. There is no blanket rule on the use of opioids. Experience has shown that they often do not truly help and often cause problems. Strong opioids are generally not recommended.127 There are exceptions to this recommendation, however, and physicians should exercise clinical judgment and use opioids when they think such therapy is necessary, provided that appropriate guidelines are followed.177 “Tender points” never need injection therapy. Painful areas in muscle may respond to local injections of local anesthetics; corticosteroids are never indicated. If injections relieve pain for more than short periods of time, they may represent a reasonable therapy. In illnesses with strong psychosocial components, medically ineffective therapies can result in overall benefit to patients. The circumstances where dubious therapies might be used are limited. The physician should understand clearly why he or she is administering such therapies and what results are anticipated. Physical Therapy and Spa Treatment Physical therapy is not recommended because the aerobic exercise required in fibromyalgia does not usually require formal physical therapy and increases medicalization. Because medical therapy is unsatisfactory, patients find their way to alternative therapies. Some of these therapies may be helpful to individual patients such as massage, water therapy, spa treatment, and acupuncture. These therapies tend to have high cost-effectiveness ratios, and the decision to use such therapies is often best left to the patients and the reimbursement authority. That is not to say that such treatments do not help—everything helps—but they do not help often enough and importantly enough, and some decision point is required. One important goal of therapy is to reduce medicalization and increase independence. In Europe and the Mediterranean a long-standing tradition of spa treatments exists and many U.S. patients, especially those whose parents came from Europe, fly over to be treated. It appears that fibromyalgia patients significantly improve after different spa treatments. In a controlled study in Tunis there was a significant improvement directly after 2 weeks of treatment and after 3 months regarding general well-being, function, pain, depression, and fatigue in 58 fibromyalgia patients compared with 76 controls.175,178 Comparable results were seen in Turkey179 and the Dead Sea in Israel.180 Reviews showed good results of spa treatment and hydrotherapy regarding pain, general well-being, and tender points continuing after 14 weeks,181,182 and a EULAR advisory committee concluded that treatment with hot baths with or without exercises had a good effect in fibromyalgia.127 Complementary or Alternative Treatments There is insufficient evidence on any complementary and alternative medicine or alternative treatment, taken orally or applied topically for fibromyalgia. The small number of positive studies lack replication. A frustrated physician may not know where to turn next in a nonresponsive patient. Should the patient be referred to a pain clinic? Sometimes such a referral is inevitable. The quality of pain clinics varies, however, and the results in fibromyalgia are often not good. The decision to refer should depend on the experience with the available clinics and the results that they have produced. In some countries, reimbursement authorities limit referrals, providing a costeffectiveness analysis that may be alien to the physicianpatient relationship. Treatment options sort themselves out over time. Decisions that are difficult resolve. In the end, the physician who provides support and interest is a strong resource and a guide for patients with fibromyalgia, even when medical therapies are limited. Medicolegal Issues and Fibromyalgia Frequently, fibromyalgia becomes a medicolegal issue when an individual with fibromyalgia asserts that he or she is unable to work because of fibromyalgia. Because fibromyalgia symptoms are felt only by the patient, there are no objective medical findings to help in the disability assessment. Gaining a disability award is complex, depending on the source of payment (e.g., government vs. private insurance), the physician’s belief and documentation, the availability of legal services, and the impact of the illness on the patient. Various guidelines have been suggested for evaluating disability as they apply to fibromyalgia. Determination of disability does not depend on proving the existence of fibromyalgia. The second medicolegal issue arises when an individual claims that trauma caused him or her to develop or exacerbate fibromyalgia and that the fibromyalgia is disabling. Although it is proposed that trauma can alter the CNS CHAPTER 52 (“neural plasticity”) and cause fibromyalgia, the relationship between the severity of trauma and the report of fibromyalgia is weak. There is no way to determine scientifically if trauma causes or caused fibromyalgia. In addition, it is often difficult to establish the severity of the fibromyalgia symptoms. In reality, the relationship between trauma and disability does not require a diagnosis of fibromyalgia because symptom severity and work impairment are important, not the presence or absence of fibromyalgia. OUTCOME OF FIBROMYALGIA The outcome of fibromyalgia can be studied in the context of change and level of symptoms, use of services, and work disability. Many studies have addressed the issue of outcome. Some have suggested that “ … knowledge of the potential reversibility of the syndrome [is] resulting in improved outcomes”183 and that “ … outcome is good with minimal intervention.”184 In a prospective study of fibromyalgia patients referred to a specialty clinic, 70 of 82 were reassessed after 3 years. The returnees were generally improved (pain reduced from 6.8 to 5.4 and fatigue reduced from 6.8 to 5.7). The authors concluded that the overall outcome was favorable.185 In 33 of 51 patients seen 6 to 8 years after initial participation in a fibromyalgia treatment study, pain was reduced from 6.7 to 5.3 and fatigue was reduced from 7.5 to 6.5. The authors concluded that the results of these returnees suggest a benign long-term outcome in patients with fibromyalgia.186A six-center, 7-year study of 538 patients noted that, “Although functional disability worsened slightly and health satisfaction improved slightly, measures of pain, global severity, fatigue, sleep disturbance, anxiety, depression, and health status were markedly abnormal at study initiation and were essentially unchanged over the study period. Half the patients are dissatisfied with their health, and 59% rate their health as fair or poor.”122 In one report of 45 of 70 patients who had participated in a 3-week trial 6 years earlier, symptoms of fibromyalgia persisted over 6 years.121 A study of prediagnosis and postdiagnosis use of services found that no changes in the high-use rates were seen over time.136 In a longitudinal study of 1555 fibromyalgia patients during 7448 semiannual observations for up to 11 years, there was minimal improvement in symptoms. The SMDs (improvement effect sizes) between start and study completion were patient global, 0.03; pain, 0.22; sleep problems, 0.20; SF-36 PCS, 0.11; SF-36 Mental Component Summary, 0.03; and EuroQoL (EQ-5D), 0.10. These data suggested that the course of fibromyalgia was one of continuous high levels of self-reported symptoms and distress despite available treatments.187 A study of 27 of 48 (56%) patients had a 2-year follow-up.188 In general, the patients showed no improvement in their symptoms over the observation period, regardless of the type of therapy they had received. General satisfaction with quality of life improved, as did satisfaction regarding health status and the family situation, although the degree of pain experienced remained unchanged. In comparison with the initial examination, there was no change in either work capacity or disability-pension status. Taken as a whole, although some patients improve, the data tend to suggest minimal improvement in most cases | Fibromyalgia 749 despite treatment. Even among the positive studies cited, the degree of improvement is small. 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