Fibromyalgia: What It Is and How to Treat It

Psychiatric Times, Vol 38, Issue 8,

This CME covers the ins and outs of fibromyalgia, and everything a mental health professional needs to know when dealing with it.

CATEGORY 1 CME

ACTIVITY GOAL

After reading this article, clinicians should be able to identify the symptoms of fibromyalgia and have several options for distinguishing fibromyalgia from conditions with similar symptoms.

Learning Objectives

1. Recognize the difficulties in diagnosing fibromyalgia in the presence of mental disorders

2. Learn about the current recommendations for treating fibromyalgia

TARGET AUDIENCE

This accredited continuing education (CE) activity is intended for psychiatrists, psychologists, primary care physicians, physician assistants, nurse practitioners, and other health care professionals who seek to improve their care for patients with mental health disorders.

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Physicians’ Education Resource®, LLC designates this enduring material for a maximum of 1.5 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

This activity is funded entirely by Physicians’ Education Resource®, LLC. No commercial support was received.

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This accredited CE activity may or may not discuss investigational, unapproved, or off-label use of drugs. Participants are advised to consult prescribing information for any products discussed. The information provided in this accredited CE activity is for continuing medical education purposes only and is not meant to substitute for the independent clinical judgment of a physician relative to diagnostic or treatment options for a specific patient’s medical condition.

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Fibromyalgia (FM) is one of the most controversial diagnoses in the field of pain management. Some experts believe that it does not exist and actually represents an accidental or purposeful misdiagnosis of other conditions, while others believe that it is badly underdiagnosed.1

The truth likely falls somewhere between these 2 extremes. FM is certainly a real syndrome, but it is also perhaps overdiagnosed, both because many physicians are unaware of the actual diagnostic criteria, and because there may be a desire to avoid diagnosing patients with other conditions that could explain the symptoms of FM—most notably mental disorders.

Fibromyalgia Diagnosis Through the Years

Over the years, the medical understanding of FM has evolved. It has gone from being viewed as a pain disorder to being considered a multisymptom syndrome that falls on a continuum, depending on the number and severity of the symptoms.2

There are no universally agreed-upon definition diagnostic criteria for FM. At minimum, it is generally agreed that there is chronic pain spread throughout the body. However, even here there is some ambiguity. For example, the current International Statistical Classification of Diseases and Related Health Problems (ICD-10) diagnosis for FM says it can be “an acute, subacute, orchronic” painful state, although it also describes FM as “a chronic disorder.”3

What appears to have been the first attempt to develop formal diagnostic criteria was presented by Smythe and Moldofsky in 1977.4 Because of the many competing definitions of FM that emerged over time, the American College of Rheumatology (ACR) sought to develop a clear set of diagnostic criteria, which it issued in 1990.5 The most significant criteria were that 1) generalized pain was present for at least 3 months; 2) the pain was present in at least 3 of 4 body quadrants; and 3) the patient had pain to pressure of up to 4 kg/cm2 as measured by an algometer at more than 11 of 18 points throughout the body.

The establishment of formal criteria resulted in FM being included as a diagnosis in the ICD in 1992. However, over the years, concerns grew about using these criteria, especially the identification of tender points, because it appeared that many physicians did not know how to accurately determine their presence or how much pressure to apply to elicit pain.

To address these concerns, the ACR revised its criteria in 2010.6 The requirement for tender points was eliminated, and the ACR instead based the diagnosis primarily on 2 scales: The Widespread Pain Index (WPI) and the Symptom Severity scale (SS).

The WPI asks whether pain has been present during the previous week in 1 of 19 locations in the body (Table 1).6 The SS scale consists of 2 parts: 1) asking about the presence and severity offatigue, waking feeling unrefreshed, and cognitive symptoms during the past week and scoring them on a 0 to 3 scale; and 2) asking about the presence of any of 41 potential symptoms, including depression, fatigue, constipation, diarrhea, rash, chest pain, and headaches during the previous week and adding the total number of symptoms to obtain a score.

A diagnosis of FM requires either a WPI score ≥ 7 and SS ≥ 5 or a WPI between 3 and 6 and SS ≥ 7.

Since the development of the 2010 ACR criteria, the work group has published 2 revisions. The 2011 revision recommended modifying the SS scale so that it could be self-administered by patients and not require physicians to determine the presence or extent of the severity of the pain.7 The 41-item checklist was replaced with a score representing the sum of scores for 3 items:headaches; pain or cramps in the lower abdomen; and depression symptoms. The authors created a fibromyalgia symptom scale that combined elements of the WPI and SS. It inquired about the locations of pain, the presence and severity of fatigue, the presence of pain or cramps in the lower abdomen, and the presence of depression and headaches.

The most recent suggested revisions were published in 2016.8 The major recommended changes were that although FM could still be diagnosed with a WPI less than 7 and SS greater than 5 (the 2010 criterion), it could also be diagnosed with a WPI between 4 and 6 and an SS greater than 9. It also recommended adding criteria of generalized pain in at least 4 of 5 regions (leftupper, right upper, left lower, right lower, axial) with jaw, chest, and abdominal pain not included, and symptoms being present at a similar level for at least 3 months.

The greatest change in the 2016 revision was the recommendation that a diagnosis of FM should not require the exclusion of other illnesses that could present with similar symptoms.

These recommendations have yet to be formally adopted, and I have great concerns about allowing FM to be diagnosed along with other disorders that can cause widespread pain and other similar symptoms—most notably mental health disorders. I believe that FM is already overdiagnosed, and if it is diagnosed despite the presence of other conditions, then it could become the focus of clinical attention while other conditions that need to be treated may be largely ignored.

A more recent proposal for diagnostic criteria was developed by ACTTION (an acronym for a public-private partnership of a study network for analgesic, anesthetic, and addiction and the US Food and Drug Administration [FDA]) and the American Pain Society (APS). It was published in 2019.9

The ACTTION APS Pain Taxonomy criteria include (1) multisite pain defined as pain at 6 or more of a possible total 9 sites (head, left arm, right arm, chest, abdomen, upper back and spine, lower back and spine including buttocks, left leg, right leg); (2) moderate to severe sleep problems or fatigue; and (3) the pain and fatigue or sleep problems must have been present for at least 3months. Although the criteria note that the presence of another pain disorder does not rule out the diagnosis of FM, it does recommend a clinical assessment to evaluate for any condition that could account for the symptoms or contribute to their severity.

The ICD-10 criteria for FM are largely descriptive, calling it “a chronic disorder of unknown etiology characterized by pain, stiffness and tenderness in the muscles of neck, shoulders, back,hips, arms, and leg. Other signs and symptoms include headaches, fatigue, sleep disturbances, and painful menstruation.” It also notes that it is characterized by “multiple points of focal muscle tenderness to palpation (trigger points)” and that “Fibromyalgia makes you feel tired and causes muscle pain and ‘tenderpoints.’”3

Which set of criteria is the correct or best one remains an open question. When examining patients who I believe may suffer from FM, I have continued to examine for tender points in addition to using the WPI and SS scales. Mental disorders are possible etiologies for widespread pain but are commonly overlooked. With this in mind, I make sure to evaluate for their presence and donot, as is commonly done, simply write off depression and anxiety as only being due to the pain. Unfortunately, as most pain specialists in this country are anesthesiologists and FM has, for the most part, been considered the province of rheumatologists, careful evaluation for mental health disorders is likely to be rare.

Etiology

The etiology of FM remains unclear. For decades, it was viewed as a musculoskeletal or rheumatologic disorder. More recently, it is being considered a neurologic disorder, in large part because the medications that were found to be most efficacious for treating FM were those that were also most effective for neuropathic pain syndromes.

The present thinking is that FM is most due to some form of central nervous system dysfunction, resulting in increased sensitization to pain.10-12 However, why it develops in certain individuals but not others largely remains a mystery.

Demographics

Measurements of the prevalence of FM have varied because of the different diagnostic criteria used to diagnosis it. Estimates have varied from 1.2% to 5.4%.13 Another major problem is that only about 25% of patients who report having FM have actually been diagnosed by a physician, and many of those who are diagnosed do not actually meet any formal diagnostic criteria for it.

Although FM is considered to occur more frequently in women, there is debate about the degree to which this is true.14 There is some concern that because women appear to be more likely than men to complain of pain to their health care providers, they are therefore more likely to receive the diagnosis.15 There is also an ongoing debate about whether pain is taken less seriously in women than in men and whether women are more likely to be simply given the diagnosis of FM, rather than receiving a full work-up to determine the presence of any underlying conditions that might be causing the pain.15 Furthermore, the female-to-male ratio has varied widely depending upon which diagnostic classification has been employed.2

Being middle-aged or older appears to increase risk. However, FM can occur at any age, and some reports suggest that a juvenile form of FM might exist.16

The presence of musculoskeletal disorders has also been reported to be a risk factor. However, there is the question of whether in at least some cases the symptoms of musculoskeletal disorders might be confused with those of FM. Other possible risk factors include high body mass index (BMI), cigarette smoking, and performing heavy or repetitive work (Table 2).13

What have been described as bidirectional relationships (ie, each appears to be a risk factor for the other) between FM and migraine headaches, irritable bowel syndrome, gastroesophageal reflux disorder, and diabetes have been reported.13

Disorders With Similar Symptoms

There are no objective tests to make the diagnosis of FM, so it is essentially a diagnosis of elimination, where other possible explanations for widespread pain are considered and ruled out. Because pain is such a common symptom, disorders of virtually every organ system can result in the symptoms of FM (Table 3).17

Many of these other conditions include symptoms that are not a part of FM and there are usually abnormalities on diagnostic tests. Notably, these include systemic inflammatory rheumatic diseases that, in addition to widespread pain, can present with other physical symptoms including skin rashes, vasculitis, and adenopathy, as well as with abnormal erythrocyte sedimentation rate and C-reactive protein, and joint abnormalities on radiographic imaging.17

Endocrine and infectious disorders, including thyroid abnormalities and hepatitis C, also present with additional symptoms and can be diagnosed with laboratory tests.

Many medications have widespread pain as an adverse event. These include statins, opioids, chemotherapeutic agents, and bisphosphonates.17 If patients are taking any of these, the pain would be considered likely to be secondary and, depending on the severity of the pain, alternative medications would be considered if available for the primary condition.

The most difficult disorders to differentiate from FM are mental disorders that also cause widespread pain. Obviously, there are no objective tests to make these diagnoses, which means that clinicians must consider and weigh which diagnosis is the most likely.

Widespread pain is a common symptom of both depressive and anxiety disorders. Also, both are often accompanied by disordered sleep, which itself can result in the symptoms of FM in healthy individuals. Because many patients with chronic pain suffer depression as a result of the pain, FM can be a primary disorder with depression secondary to it.

The best way to differentiate FM from a mental disorder is to determine whether the mental disorder preceded the onset of the pain, or whether the patient has a family history of mental disorders that might make them more prone to developing these conditions.

One of the many as-yet-unanswered questions about FM is whether certain mental disorders might predispose patients to developing it. Of recent interest is an association between posttraumatic stress disorder (PTSD) and FM with underlying childhood abuse.18,19 As with depressive and anxiety disorders, pain itself can be a symptom of PTSD. It is unclear whether patients with symptoms of this disorder and pain only are suffering from this or also have comorbid FM.

Psychosocial stresses are possible contributing factors in the development of FM or in the exacerbation of its symptoms. These stressors are often overlooked and therefore not addressed.18

Treatment Options

As with most types of chronic pain, FM can be difficult to treat, but a number of therapies have been shown to provide benefit. A recent review of treatments for FM identified several that appear to be effective.20

Medication Management. With regard to medications, the classes of medications that seem to be most beneficial for FM are the serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressants and central nervous system depressants, primarily anticonvulsants.18 These medications have the highest level of support for their use based on controlled studies (Table 4).20

This fits with the medications currently approved by the FDA for the management of FM: the SNRIs venlafaxine and milnacipran and the anticonvulsant pregabalin. It should be noted that other medications in the same classes, most notably the tricyclic antidepressants (TCAs), especially amitriptyline, and other anticonvulsant medications, especially gabapentin (a gabapentinoid likepregabalin), have been found to be beneficial.

Whether the FDA-approved medications are more efficacious than others with similar modes of action is an open question, as there is scarce research comparing the various medications to oneanother. Most of the studies demonstrating the efficacy of these other medications were performed after the drugs were no longer under patent, so there was minimal financial benefit for manufacturers to formally seek approval of these for treatment of FM.

Whether amitriptyline is more effective for FM than other TCAs is also unknown. The strong sedative effect of this medication, which may be beneficial for sleep problems experienced by many with FM, may provide some advantage over less-sedating TCAs.

Nonsteroidal anti-inflammatory drugs may provide some benefit for FM but appear to less efficacious than the SNRIs and anticonvulsants. One class of medications that is frequently prescribed to patients with pain, opioids, appears to provide little benefit to FM patients. The risk for adverse events associated with the use of opioids, most notably opioid abuse, is considered to outweigh whatever benefit they might provide.

A limitation of virtually all the studies on medications is that most report short- or medium-term results, leaving open the question of long-term efficacy, which is an important issue, considering that FM is a chronic condition.

Nonpharmacologic Therapies. Of the nonpharmacologic therapies, 2 appear to be especially efficacious.17 The first is aerobic exercise, which can be beneficial for many chronic painconditions. Unfortunately, because patients may experience increased pain as they begin to exercise, they may take this as a sign that the exercise is exacerbating the pain and thus an indication to do less exercise. It can be helpful for patients to work with physical and occupational therapists, as these professional can instruct patients in proper ways to exercise and encourage them to continue (even if they initially experience increased pain) and in methods to perform daily activities that are less likely to exacerbate the pain.

The second nonpharmacologic therapy is cognitive behavioral therapy (CBT). Patients with FM can often benefit from CBT by focusing on the ways pain and other symptoms interfere with their lives and addressing this.

Patients may resist referral for CBT out of fear that benefiting from any form of psychotherapy indicates their health care providers believe they are suffering from a mental disorder and therefore their pain is not real. Providers need to explain that undergoing CBT in no way discounts the presence of the pain and other symptoms.

A major benefit of both exercise and CBT is that they are essentially free from adverse events and therefore unlikely to exacerbate FM and symptoms, something that can occur withmedications.

Concluding Thoughts

Fibromyalgia has gone from being viewed simply as a pain disorder to being considered a complex, multisystem disorder, with widespread pain being only one of its symptoms. It is important to be aware of the diagnostic criteria for FM because other disorders, especially mental disorders, are not uncommonly misdiagnosed as FM. Finally, despite the variety of therapeutic optionsavailable, FM remains very difficult to treat.

Dr King is in private practice in Philadelphia, Pennsylvania.

References

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