It will not be surprising to hear that chronic pain is a major source of disability, suffering, and health care utilization affecting approximately 100 million US adults or more than one-third of the adult population (1).
Just one of the many causes of chronic pain is fibromyalgia (FM), a potentially disabling and poorly understood rheumatic condition. Fibromyalgia is characterized by chronic widespread pain and tenderness, fatigue, cognitive difficulties, and overall functional impairment. There is no widely accepted etiology of fibromyalgia.
The prevalence of fibromyalgia in the U.S. has been estimated to range from 2% to 8%, affecting 5 to 10 million adults (2,3). What I want to call your attention to is that fibromyalgia is most prevalent among middle-aged women, encompassing 75% to 90% of those diagnosed (4,5,6).
For many years, the diagnosis of fibromyalgia has been reliant on an evaluation of “tender points,” or areas of tenderness around joints, assessed by palpation or algometer. Women tend to report more tender points than men (7), and have also been reported to feel more intense pain at these designated tender point sites (8). One of the thoughts about the greater frequency of fibromyalgia among women has been largely attributed to this diagnostic criterion.
In 2016, the American College of Rheumatology revised their diagnostic criteria which now includes:
- Widespread Pain Index (WPI) ≥7 AND Symptom Severity Scale (SSS) score ≥5 OR WPI between 4–6 and SSS score ≥9.
- Generalized pain, in at least 4 of 5 regions, is present.
- Symptoms present at a similar level for at least 3 months.
- A diagnosis of FM is valid irrespective of other diagnoses.
– A diagnosis of FM does NOT exclude the presence of other illnesses.
It is possible that with this new diagnostic criterion, the gender difference is smaller than previously estimated. Another problem with determining the magnitude of gender difference is that there are very few men in most of the studies.
Despite efforts to develop diagnostic efforts and consistency in diagnosing fibromyalgia, not all clinicians and clinical settings apply these guidelines and at this point, there seems to be no “gold standard” for a clinical diagnosis of fibromyalgia. What makes it especially challenging, is that there is no lab or imaging test to make such a diagnosis.
Fibromyalgia is commonly associated with psychiatric disorders (3) and international research has shown high rates of depression, anxiety disorders, bipolar disorder, obsessive-compulsive disorder, personality disorders, and posttraumatic stress disorder (PTSD) in patients with fibromyalgia.
As I mentioned earlier, the underlying cause/causes of fibromyalgia remains/remain unknown, although there is evolving insight with findings that it is associated with dysregulated dopamine in the brain (9,10). Without the tender point criteria, the diagnosis now relies exclusively on self-report data. That makes things more ambiguous and highlights the influence of anxiety and/or depression on the experience of the pain. While I’m not comfortable with it, as a result of this diagnostic ambiguity and substantial psychiatric comorbidity, fibromyalgia is frequently, and controversially, viewed as a somatoform psychiatric disorder (11,12).
A somatoform disorder also known as somatic symptom disorder (SDD) or psychosomatic disorder, is a mental health condition that causes an individual to experience physical bodily symptoms in response to psychological distress. I am concerned that characterizing fibromyalgia as a psychosomatic disorder is just too reminiscent of the disregard, disrespect and discounting of women and their health issues that have existed in medicine and our culture for decades and that still exist today.
Another comment on gender differences in fibromyalgia brings to mind a recent study that examined gender differences in the demographics and clinical correlates of musculoskeletal disorders among Veterans. Fibromyalgia was included among 14 groups of musculoskeletal disorders and was not examined separately (13). As of the writing of my column today, I’m not aware of any study that has systematically compared sociodemographic characteristics, patterns of comorbidity, health care utilization and psychotropic medication prescriptions use among patients with fibromyalgia in comparison to patients with other pain syndrome diagnoses, or between males and females diagnosed with fibromyalgia.
A new diagnostic proposal has been proposed by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks (ACTTION), a public–private partnership with the U.S. Food and Drug Administration (FDA) and the American Pain Society (APS). Their goal is to try to develop a clinically useful and consistent diagnostic system for chronic pain disorders, including FM.
What I appreciate of this new diagnostic proposal is that they conceptualize FM as a dimensional syndrome which includes five dimensions: 1- Core Diagnostic Criteria, defined as the presence of pain in six or more body sites from a total of nine possible localizations, sleep disturbance, and fatigue; 2- Common Features, like tenderness, dyscognition (e.g., trouble concentrating, forgetfulness, and disorganized or slow thinking), musculoskeletal stiffness, and environmental sensitivity or hypervigilance; 3- Common Medical and Psychiatric Comorbidities like chronic fatigue syndrome, irritable bowel syndrome, chronic pelvic pain, interstitial cystitis, orofacial conditions, chronic headaches, depression, anxiety disorders, central sleep apnea, restless leg syndrome, etc.; 4- Neurobiological, Psychosocial and Functional Consequences, which includes general outcome, functional disability, social and medical cost of FM, morbidity, and mortality; and 5- Putative Neurobiological and Psychosocial Mechanisms, Risk Factors, and Protective Factors that focus on risk factors, comorbidities, and pathophysiology aspects. This proposal is much more inclusive of the risk factors, course, prognosis, and pathophysiology of FM. We need to wait for validation of this criteria with data about accuracy of diagnosis.
If we end up using this criteria, it is likely that the diagnosis of FM would significantly increase, but also likely the false positives.
In conversations with rheumatology experts that think that FM is not a distinct rheumatological diagnosis, instead, they assert the correct rheumatological diagnosis has just not been made. While I cannot yet agree with this assertion, I do use that perspective to motivate me to be more studious and diligent in the ability to diagnosis disorders that I might have missed including rheumatoid arthritis, ankylosing spondylitis and systemic lupus but might include more challenging diagnostic situations such as small fiber neuropathy and Ehlers-Danlos Syndrome.
Many other articles and presentations have brought attention to strategies in treating FM that include: addressing and reducing stress triggers, lifestyle factors such as sleep habits and sleep quality, regulating cortisol, identifying and addressing co existing and/or underlying disorders or influences such as vitamin D insufficiency/deficiency, low iron stores, hormonal factors, toxin exposures and other chronic viruses and/or bacteria. In addition, tools of the trade might include magnesium, tryptophan, L-tyrosine, vitamin D, omega-3 fatty acids, saffron, palmitoylethanolamide (PEA), malic acid, ribose, SAMe, curcumin, low dose naltrexone, California poppy and other traditional plants.
I look forward to reading other articles that continue to gain insight and consider other ideas and knowledge about addressing this very complex and challenging disorder.
References
- Gaskin DJ, Richard P. The economic costs of pain in the United States. J Pain 2012;13:715–724
- Wolfe F, Ross K, Anderson J, Russell IJ, Hebert L. The prevalence and characteristics of fibromyalgia in the general population. Arthritis Rheum 1995;38:19–28
- Clauw DJ. Fibromyalgia: A clinical review. JAMA 2014;311:1547–1555
- Bennett RM, Jones J, Turk DC, Russell IJ, Matallana L. An internet survey of 2,596 people with fibromyalgia. BMC Musculoskelet Disord 2007;8:27.
- Robinson RL, Kroenke K, Williams DA, et al.. Longitudinal Observation of Treatment Patterns and Outcomes for Patients with Fibromyalgia: 12-Month Findings from the REFLECTIONS Study. Pain Med 2013;14:1400–1415
- Wolfe F, Hassett AL, Walitt B, Michaud K. Mortality in fibromyalgia: A study of 8,186 patients over thirty-five years. Arthritis Care Res 2011;63:94–101
- Wolfe F, Cathey M. The epidemiology of tender points: A prospective study of 1520 patients. J Rheumatol 1985;12:1164–1168
- Buskila D, Neumann L, Alhoashle A, Abu-Shakra M. Fibromyalgia syndrome in men. Semin Arthritis Rheum 2000;30:47–51
- Wood PB, Schweinhardt P, Jaeger E, et al.. Fibromyalgia patients show an abnormal dopamine response to pain. Eur J Neurosci 2007;25:3576–3582
- Albrecht DS, MacKie PJ, Kareken DA, et al.. Differential dopamine function in fibromyalgia. Brain Imaging Behav 2016;10:829–8394
- Häuser W, Ablin J, Fitzcharles M, et al.. Fibromyalgia. Nat Rev Dis Primers 2014;1:15022
- Häuser W, Henningsen P. Fibromyalgia syndrome: A somatoform disorder? Eur J Pain 2014;18:1052–1059
- Higgins DM, Fenton BT, Driscoll MA, et al.. Gender differences in demographic and clinical correlates among Veterans with musculoskeletal disorders. Women’s Health Issues 2017;27:463–470
