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13 Articles in Volume 11, Issue #7
Fibromyalgia: Practical Approaches To Diagnosis and Treatment
Juvenile Fibromyalgia: Diagnostic Challenges and Treatment Options
Aqua Therapy Helpful in Treatment Of Systemic Lupus Erythematosus
Axial Neck Pain, Radiculopathy, and Myelopathy: Recognition and Treatment
Early Treatment of TMD May Prevent Chronic Pain and Disability
Identifying Psychological Factors That Influence Surgical Outcomes
Managing Morton’s Entrapment
Premedicated Mask May Hold Promise for Migraine Patients
Mother With Low Back Pain
The Hip Replacement Patient
Evidence-based Medicine: Losing the Patient’s Voice?
What Is Going Wrong With Research?
Risk for Sedation and Car Accidents

Fibromyalgia: Practical Approaches To Diagnosis and Treatment

In part 1 of this two-part series on the presentation, diagnosis, and treatment of fibromyalgia, the author reviews the epidemiology of fibromyalgia and discusses new diagnostic criteria.

Fibromyalgia (FM) syndrome is a common clinical disorder that is characterized by chronic widespread pain. Although pain is the most prominent symptom, there are many other manifestations that mix and match as they contribute importantly to the morbidity of FM.

Gone are the days when FM was considered a psychological disorder. Growing objective evidence shows that FM is a disorder of the central nervous system. Much is known about its clinical presentation, diagnosis, pathogenesis, epidemiology, natural history, and treatment. Thus far, the FDA has approved three mechanism-based medications to treat FM.

The challenge for the future is to identify symptomatic patients earlier in their clinical course in hopes of reducing the potential for development of long-term disability.

The goal of this two-part series is to provide a practical, quick, and easy summary of FM. This installment focuses on the epidemiology of FM and discusses new diagnostic criteria endorsed by the American College of Rheumatology (ACR). In Part 2, we review treatment strategies for managing patients with this disease.

Epidemiology of Fibromyalgia
It has been estimated that FM affects approximately 2% of the general population, or about 5 million Americans.1 The disorder is found in all ethnic groups and is not limited to developed or industrialized countries. Adult women are up to seven times more likely than adult men to have FM, and the prevalence of the disorder increases with age, most dramatically in women with a peak in the fifth to seventh decade (7.4%-10%).1 The risk for having or developing FM in a family with one affected member is about 8.5-fold greater than in a family without any affected members.2 Although seen most commonly in middle-aged women, FM also is seen in children and teenagers.3-5 (For a review of juvenile FM, please see related article on page 81.)

Researchers have identified a number of risk factors for the development of FM, including the following:

  • Familial/genetic predisposition3,6
  • Physical trauma.7 (People with whiplash are more likely to develop systematic FM than industrial accidents limited to lower extremity fracture; 22% vs. 2% for all subjects, >30% for female accident victims.)8 Narrowed cervical canal may be an important risk factor for the development of chronic pain and cord pathology following a whiplash injury.9,10
  • Major febrile illness

Classification of Soft Tissue Pain Syndromes
Fibromyalgia is just one of more than 200 musculoskeletal conditions that can cause body pain and interfere with mechanical function. It is logical to divide these into two nearly equal categories of those that actively involve the joints (eg, arthritis) and those that do not.

There has been much confusion in terminology surrounding the arthritis group where joint involvement is not the focus. Some of the confusion results from misunderstanding about the myofascial pain syndrome (MPS). Clinicians who have heard of MPS but are not skilled in its diagnosis often use the term myofascial pain generically. A better umbrella term is soft tissue pain (STP).11 It can be used in clinical charts as both a historical and an examination category.

Table 1 provides a useful classification of STP with three main subheadings:

1.  Local conditions: Most are believed to result from repetitive mechanical injury to inadequately conditioned tissues. They are named anatomically and can be disclosed by a typical history of localized pain plus exquisite tenderness of the affected structure elicited by firm digital palpation. Examples include biceps tendinitis and trochanteric bursitis.

2.  Regional syndromes are limited in anatomic scope to a region or quadrant of the body, as seen with MPS and complex regional pain syndrome (CRPS).

3. The generalized category implies a systemic process like that of FM, which affects the musculoskeletal system in a more global manner. There is no clear evidence to suggest that a localized STP condition can evolve into a regional STP condition or that any of the regional STP disorders can morph into a generalized category condition. Examples include FM and chronic fatigue syndrome when it is painful, hypermobility syndrome.

Making the Diagnosis

The 1990 ACR Criteria
Early in the course of FM studies, the condition was called fibrositis and each investigator had developed diagnostic criteria that seemed to apply. That situation changed when a collaborative research study led to the 1990 ACR Research Classification Criteria (ACR RCC) for fibromyalgia.12 It is emphasized that these criteria were intended to identify subjects for research study but not for medical care.

Two components were required: one from the patient’s medical history (chronic widespread pain for at least 3 months) and one from the physical examination (11 of 18 painfully tender soft tissue sites) (Table 2).

2010 ACR Diagnostic Criteria
Both components of the 1990 ACR RCC were based on the domain of pain in FM but they completely ignored the comorbid domains, that are so troublesome to many patients with FM (Table 3).

There clearly was a need for validated clinical criteria that would also focus on FM comorbid manifestations such as sleep dysfunction, headache, cognitive dysfunction, affective manifestations, fatigue, chest pain, irritable bowel syndrome, and bladder irritability. On the basis of that need, a new approach to clinical diagnosis of FM was developed.12,13

As with the 1990 ACR RCC, the new criteria, called the 2010 ACR Fibromyalgia Diagnostic Criteria (2010 ACR FDC), were established from the results of a clinical study. The 2010 ACR FDC viewed the 1990 ACR RCC as the gold standard but did not require tender-point examination. Critically, the 2010 ACR FDC was validated for the setting of clinical medical care.

As with the 1990 ACR RCC, the 2010 ACR FDC has two components: the Widespread Pain Index (WPI) and the Symptom Severity Scale (SSS).

  • The WPI represents an attempt to quantify how large a proportion of the patient’s anatomy was experiencing pain. Table 4 provides a listing of discrete areas of the body where the existence of pain would contribute to the WPI. Each affected area increased the WPI by 1 point, with a range of possible scores from 0 to 19.
  • The SSS quantified the severity of comorbid involvement with
    a possible range of values from 0 to 12. Three comorbid domains characteristic of FM (morning tiredness, daytime fatigue, cognitive dysfunction) are quantified: absent = 0, mild = 1, moderate = 2, or severe = 3. Additionally, a list of 41 potential comorbid symptoms or signs is provided to represent an FM-related review of symptoms. The magnitude of their contributions to the patient’s behavior were categorically quantified from 0 = none, 1 = few (1-10), 2 = many (11-30), to 3 = very many (31-40).

The 2010 ACR FDC total score was dependent on a floating combination of scores for the WPI and the SSS. For example, the diagnosis of fibromyalgia could be made with WPI of 7 or greater and SSS of 5 or greater or with WPI of 3 to 6 and SSS of at least 9. These criteria were 93% accurate, with 97% sensitivity and 92% specificity, which meant that they identified essentially the same individuals who were diagnosed as having FM through the 1990 ACR RCC (Table 5).

Self-administered Questionnaire
A self-administered questionnaire was developed as an extension of this methodology.14 Using that format, when the simple sum of the WPI and the SSS was equal to or greater than 13, the diagnosis of FM was confirmed. Thus, a clinical subject entering a doctor’s office can complete a questionnaire and have it easily scored by a trained paramedical staff member.

There is acknowledged risk with a questionnaire format that an occasional patient might attempt to manipulate the outcome for personal gain. In most countries, it is the physician who conducts the medical history, performs the examination and makes the diagnoses, so it is still possible for the physician to reject the findings of the self-report instrument and deny the suggested diagnosis.

If that happens, the patient may be no more likely to receive sophisticated care for his or her FM symptoms based on the 2010 ACR FDC than that same clinician would have offered in the era of the 1990 ACR RCC. Alternatively, if the physician blindly accepts a diagnosis made by a questionnaire, the prevalence of FM could gradually expand from the 2% of the general population found to have FM according to the 1990 ACR RCC, until that diagnosis applies to the entire 10% of the general population with chronic widespread pain.4

The point is that the diagnostic approach used is not the key to good medical care for patients with FM. It is merely an important component of the process that should be done well, with a view to providing effective care once the diagnosis has been made.

Differential Diagnosis
Although many physicians believe FM is a diagnosis made by exclusion, this should not be the case. Fibromyalgia is a diagnosis made on the basis of clinical criteria. Thus, when the 2010 ACR FDC criteria are met, it is appropriate to classify the affected patient as having FM—irrespective of, or in addition to, any other legitimate medical diagnoses. This rule applies even if the concomitant illness is one that typically exhibits pain as a symptom.

Because the most prominent complaint of patients with FM is body pain, the differential diagnosis should consider a wide variety of other painful conditions, as well as several types of clinical consequences of chronic widespread body pain.

The other critical role of the clinician is to consider comorbid conditions. Inflammatory diseases and endocrine disorders can develop insidiously. Chronic pain conditions can be associated with psychosocial complications. Clues that suggest an overlap with major depression, panic, or other anxiety-related disorders must be carefully considered. At the first and every subsequent visit, it is incumbent on the clinician to remain alert to detect concomitant conditions that may accompany FM symptoms.

When FM occurs alone, it’s called “primary FM.” Conversely, patients with other chronic diseases can develop FM at any time in the course of their symptoms. For want of better terminology, in the setting of another painful condition or inflammatory condition, the FM component has been referred to as “secondary FM.”

Secondary Fibromyalgia
In secondary FM, it is not necessarily perceived that the FM component is caused by the other condition, but the terminology has become entrenched, and now serves a communication need. Secondary FM may not be clinically distinguishable from primary FM12 but increasingly laboratory and clinical findings do distinguish these FM subgroups.15-19

Rheumatic Disease
As examples of secondary FM, nearly 30% of patients with rheumatoid arthritis, 40% of patients with systemic lupus erythematosus, and 50% of patients with Sjögren’s syndrome also have FM.20-23 Patients with a rheumatic disease and FM seem to experience articular pain out of proportion to the otherwise apparent severity of their rheumatic disease.

This must be considered in treating the rheumatic condition because increasing the dosage of antirheumatic medications in the absence of active inflammation may have little effect on the pain amplified by FM. Conventional wisdom says that the best results are obtained by treating each of the conditions separately.

Patients with a rheumatic disease and fibromyalgia who are treated with glucocorticoids (GCs; eg, prednisone) for the rheumatic disease should be warned that a transient increase in FM symptoms may occur with each decrease in GC dosage (steroid-withdrawal FM). Thus, the stable FM therapy may need to be increased transiently.

This is a surprising phenomenon because GC is not helpful in treating primary FM.24 To avoid interference with a steroid taper, it is best to decrease the dosage gradually—approximately 2-week intervals. The rate of the taper depends on the current dosage. For patients on a GC dosage that is equivalent to 60 mg per day of prednisone, step down should be directly to 30 mg per day; then by 5 mg-dose steps from 30 mg per day to 15 mg per day; then by 2.5 mg-dose steps to 5 mg per day; then by 1 mg-dose steps until the patient is off the medication.

Infectious/Inflammatory Conditions
Infectious/inflammatory conditions that seem to be associated with FM include hepatitis C, tuberculosis (TB), syphilis, and Lyme disease. The prevalence of each overlap will depend on the prevalence of the infectious disease in the community.

An academic practice in a Lyme-endemic area evaluated 788 patients with an apparent spirochete infection for a mean of 2.5 years.25 Twenty percent of patients infected with Lyme disease met criteria for FM. This is clearly higher than the 2% prevalence of FM in the general community.

The symptoms of FM developed within 1 to 4 months after infection—often in association with Lyme arthritis. The signs of Lyme disease generally have resolved with antibiotic therapy, but the FM symptoms often have persisted. The largest subgroup of the 788 patients did not have Lyme disease but met criteria for FM or chronic fatigue syndrome.

An association between subacute bacterial endocarditis and FM has not been formally explored, but the characteristic somatic symptoms associated with endocarditis (arthralgias, myalgias) suggest that diagnostic confusion could occur.26

Testing
Although the diagnosis of FM is established by diagnostic criteria rather than by exclusion, it is still important to maintain a wide differential. A common mistake in this setting assumes that every symptom and sign presenting in an FM patient is due to the disorder. Another mistake is “shotgun medicine,” which includes almost blindly ordering tests—especially expensive imaging tests—when clinical recognition of FM would likely suffice.

Table 6 provides a two-level approach to testing patients with FM. The first level of inexpensive tests is considered routine and applicable to any patient on the occasion of the initial diagnostic assessment. Some requisites apply here, however. For example, some of the infection-related tests may be more appropriate in one region of the country than in others; for example, TB is endemic in southern Texas, whereas Lyme disease is more prevalent in Connecticut.

The TB skin test, known as the PPD (purified protein derivative), is gradually being replaced by an in vitro test called QuantiFERON Gold. Many people with FM complain of “bone pain,” and vitamin D deficiency is more common in people whose chronic illness prompts them to avoid sun exposure. 25-Hydroxy vitamin D should be measured in all new patients diagnosed with FM. If the result is low, bone pain could result from osteomalacia. Dual-energy x-ray absorptiometry (DXA) should be reserved for those patients with documented low vitamin D levels.

Patients may have reason not to fully disclose all of the substances being used to treat their pain. A urine screen for drugs and medications is indicated at baseline to help the clinician design a comprehensive treatment strategy.

The second level of diagnostic evaluation is much more expensive and should be viewed as discretionary. Those tests should be invoked only when the findings from a careful medical history and examination indicate a need for more extensive evaluation—not for the FM, but for coexistent medical disorders.

Summary
Fibromyalgia is a common clinical disorder that exhibits pain and many comorbidities. There is objective physiologic, imaging, and biochemical evidence to support the concept that the patients with FM actually experience the pain that they describe.

Part 2 of this educational review will discuss treatment options. Multimodal therapy, involving pharmacologic and nonpharmacologic interventions, is the contemporary optimal approach to managing FM. Pharmacologic therapy of FM has become increasingly focused on the correction of documented molecular-level abnormalities. Rational strategic polypharmacy with two or more agents directed at different molecular mechanisms will likely represent the important clinical therapeutic innovations of the next decade.

Last updated on: February 20, 2015
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