Challenges of Pain in Fibromyalgia

Fibromyalgia (FM) is a common pain disorder predominantly affecting women, with onset at any age.¹ In addition to widespread pain, people with FM report sleep and mood disturbances, suggesting a central etiology. Many conceptualize FM as a disorder resulting from central sensitization of the nociceptive sensory nervous system. FM is a clinical diagnosis, based solely on a pattern of clinical symptoms and signs not better explained by another disorder. As such, FM is diagnosed after other disorders—with specific mechanisms and, consequently, testing—are excluded, including other rheumatologic and neurologic disorders. As a diagnosis of exclusion, other treatable causes of the symptoms (eg, systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, hypothyroidism, and diabetic peripheral neuropathy [DPN] must be ruled out. On the other hand, a diagnosis of FM should be made in its own right. based on widespread pain and tenderness, with associated psychologic comorbidities. A further challenge is that FM is frequently a comorbid condition in individuals with another rheumatologic or neurologic condition.

Diagnosis

A major challenge in FM diagnosis is the broad range of complex symptoms. Psychologic symptoms frequently escape the attention of busy clinicians. The evolution of the diagnostic criteria of the American College of Rheumatology illustrate this challenge well. The most recent consensus requires physician physical examination, a Widespread Pain Index (WPI), and a Symptom Severity Scale (SSS). The WPI is a self-reported list of 19 distinct and diffuse areas described as painful during the past 7 day period with 1 point for each area.^2-4 As shown in the Box, the SSS entails rating severity of fatigue, waking unrefreshed, and cognitive symptoms on a scale of 0 (never) to 3 (severe/continuous).³ The WPI also requires accompanying symptoms in the past 6 months, including headaches, lower abdominal pain or cramps, and depression (1 point each). A score of 7 or more on the WPI and 9 or more on SSS is considered diagnostic. Patients are given a final symptom severity score (FS) of 0 to 12, combining the WPI and SSS scores.² Misdiagnosis is a frequent challenge.⁵

Despite improvements to diagnostic criteria developed in 1990 and further refined by in 2010,² consensus is yet to be achieved. The lack of quantitative disease measures and an incomplete understanding of the pathophysiology of FM continue to challenge clinicians, who struggle to diagnose FM because there is no clear, objective way to do so. A corollary is that clinicians struggle to identify new acute pain conditions in people who have FM. For example, in our case study, a person with FM had evidence of a radiculopathy that had been misdiagnosed as simply an extension of her FM.

FM is more common in early adulthood and in women, who may appear physically healthy compared with people with other chronic pain disorders. The severity of symptoms, however, is debilitating. The incongruence between presentation and reality, coupled with the lack of diagnostic criteria, biomarkers, and radiologic findings can cause misunderstanding in the patient-clinician relationship.^6,7 This invalidation, only recently being addressed in clinical medicine, refers to individuals with invisible symptoms perceived by a clinician or others to be inflated or psychologic. Such invalidation can lead to dismissal and disregard by society and healthcare providers, and this may negatively affect symptom severity.^7,8 Having medical health professionals discount a person’s subjective symptoms has been correlated inversely with mental health.⁷

In addition, symptoms that overlap with may other conditions contribute to inaccurate diagnoses. For example, persons with FM share comparable sensory phenomenon to those with DPN.⁹ In a multisite study across 450 outpatient centers in Germany, 1,623 people with DPN and 1,434 with FM completed the painDETECT questionnaire to assess somatosensory symptoms, pain perception, and comorbidities. Cluster analysis was used to further stratify participants.⁹ Of those with FM, 40% experienced “severe painful attacks” vs 29% with DPN. Numbness, in contrast, was noted in 19% with FM vs 30% with DPN. Burning pain and radiating pain were noted in 30% vs 33% and 72% vs 55% in people with FM and DPN, respectively. These findings may represent an underlying common etiology.

In a survey of 189 general clinicians and 139 specialists (rheumatologists, psychiatrists, anesthesiologists and neurologists) 36% of general clinicians and 25% of specialists indicated insufficient knowledge to diagnose FM. Two-thirds (63% of generalists and 66% of specialists) noted the abstract definition, disease complexity, and subjective nature of symptoms as barriers to diagnosis.⁸ This uncertainty was perceived by some patients as inability to prescribe effective pharmacologic treatment, leading to feeling they could no longer be helped.¹⁰

Treatment

An additional challenge of FM is that best-practice care requires multimodal, multidisciplinary treatment, often not practiced or fully reimbursed. For physicians who do not have opportunity to work with the multidisciplinary pain team, this can be partly overcome by referring patients to physical education therapists, psychologists experienced in counseling patients with pain, and other health care providers who have experience in the treatment of chronic pain.

Multimodal treatment requires input from all the members of the multidisciplinary team including physicians, nursing staff, physical therapists, and psychologists, all of whom participate in care of patients with FM. Patient engagement in regular exercise—activities like regular walking, warm water therapy, yoga, and tai chi—are an important starting point and the basis of successful therapy for FM.^1,11

Pregabalin, duloxetine, and milnacipran are the 3 pharmacologic agents that are approved for treatment of FM. Although duloxetine and pregabalin are available as generic medications they remain underused. Ineffective treatments, such as nonsteroidal anti-inflammatory drugs (NSAIDs) can lead to excessive health care costs that are a burden to both patients and society via direct and indirect costs.^6,7,11 People with FM have 2.6 times more medical claims for coexisting conditions annually compared with the general population. Common prescriptions are higher than for an average beneficiary (84% vs 52%; P<.001).^11,12 Other indirect costs are related to lost productivity of presenteeism, time off work, and disability claims.^7,12-14

Summary

In summary, there are many opportunities to improve the assessment, diagnosis, and treatment of FM and the lives of people living with this condition. Although standardized diagnostic criteria are a useful step in this direction, development of quantitative measures for diagnosis and treatment will likely prove to further improve outcomes in treatment of FM pain and associated disability.