Fibromyalgia — which affects an estimated 4% to 10% of the US population, with a 7-time higher prevalence in women vs men — has remained a clinically nebulous entity, and one that is very difficult to manage effectively.1
A diagnosis of fibromyalgia is often given to people who have widespread pain with no known physiologic cause. The original American College of Rheumatology (ACR) criteria for fibromyalgia published in 1990 stipulate that, to establish a diagnosis of fibromyalgia, chronic widespread pain should be present for 3 months in at least 11 of the 18 designated tender points and in the absence of any other causes.2 “Approximately 25% of [patients with] fibromyalgia did not satisfy the ACR 1990 classification criteria at the time of the study,” reported a new guidelines committee, which in 2010 updated the criteria to include fatigue and sleep and cognitive dysfunction.3
These new guidelines no longer relied on assessment of tender points, but instead used the combined symptom severity (SS) scale and the widespread pain index (WPI), requiring the following values for a fibromyalgia diagnosis: WPI ≥7 and SS ≥5, or WPI between 3 and 6 and SS ≥9.3
Etiology of Fibromyalgia
It is thought that fibromyalgia results from a central afferent processing disorder that involves a blunting of inhibitory pain pathways and altered neurotransmission. Pain signals may be disrupted, leading to their amplification and to lower pain thresholds, phenomena which result in random pain sensations of varying intensities.4
In a review of the genetics of fibromyalgia, researchers stated that fibromyalgia involves “the interaction of several factors, including abnormalities in the neurobiological and autonomic nervous systems, genetic factors, psychological variables, and environmental factors.”4 They noted genetic factors that were common to multiple pain syndromes in general, as well as familial aggregates in fibromyalgia and comorbid psychological traits.4 Genetic studies of patients with fibromyalgia indicated the presence of polymorphisms in genes involved in serotonergic, dopaminergic, and catecholaminergic pathways that may each play a role in the development of the disease.
Pain and Fatigue in Fibromyalgia
Although defined primarily by pain, fibromyalgia remains a confusing entity for clinicians to diagnose. Recent evidence suggests that fibromyalgia is a multifactorial disorder affecting multiple systems.
The common symptom of fatigue — present in up to 80% of cases of fibromyalgia — varies with the severity of pain and other symptoms, including joint stiffness, sleep disturbances, anxiety, depression, and cognitive difficulties (often called “brain fog”), symptoms which overlap with a variety of other disorders categorized as central sensitivity syndromes.5 These include chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorder, restless leg syndrome, primary dysmenorrhea, idiopathic low back pain, multiple chemical sensitivity, tension and migraine headache, interstitial cystitis, chronic pelvic pain and endometriosis, and myofascial pain syndrome.5
Although the widespread, nonspecific tenderness often reported in fibromyalgia was thought to indicate a psychosomatic origin, brain imaging studies indicate the amplification of pain signals in several central sensitivity syndromes, including low back pain, irritable bowel syndrome, and fibromyalgia.5
Additional Fibromyalgia Symptoms
Patients with fibromyalgia often report difficulty in performing simple daily tasks such as folding laundry, getting dressed, or preparing meals as a result of their symptoms, and are particularly limited by fatigue.1 According to results of a 2015 study, patients with fibromyalgia vs healthy individuals may experience higher levels of physical fatigue after exertion and when performing cognitive tasks (eg, the Controlled Oral Word Association Test and the Valpar peg test), thus affecting the quality of life in this population.6
Few treatments are available for fibromyalgia. Fibromyalgia medications include the antiepileptic agent pregabalin and the selective serotonin norepinephrine reuptake inhibitors duloxetine and milnacipran, all of which have been approved by the US Food and Drug Administration for this indication. Other drugs used to treat specific symptoms include pain medications, antidepressants, muscle relaxants, and sleep medications.
Nonpharmacologic therapies, including weight management and regular exercise (eg, low-impact aerobics combined with weight training), are essential for the adequate management of fibromyalgia and have been shown to alleviate disease-associated symptoms and increase function. Flexibility training such as yoga and movement-based exercises such as tai chi and qi gong have shown some benefits. In a review of therapies for fibromyalgia, exercise was found to be most beneficial when combined with education on the pathophysiology of fibromyalgia to help patients dispel the notion that the associated pain is solely of a psychogenic nature.5
Other therapies include managing sleep disorders, teaching relaxation techniques, and providing behavioral interventions that primarily target pain catastrophizing often associated with chronic pain.
The most effective approach to the treatment of patients with fibromyalgia requires a careful assessment of all complaints and validation of the patient’s concerns. Such an approach allows the development of an individualized therapeutic plan that targets the patient’s most distressing and limiting symptoms.
- Dailey DL, Frey Law LA, Vance CGT, et al. Perceived function and physical performance are associated with pain and fatigue in women with fibromyalgia. Arthritis Res Ther. 2016;18:68.
- Wolfe F. Fibromyalgia. Rheum Dis Clin North Am 1990;16:681-698.
- Wolfe F, Clauw DJ, Fitzcharles MA, et al. The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity. Arthritis Care Res (Hoboken). 2010;62:600-610.
- Park D-J, Lee S-S. New insights into the genetics of fibromyalgia. Korean J Intern Med. 2017;32:984-995.
- Harris R, Smith HS, Clauw D. Fibromyalgia: an afferent processing disorder leading to a complex pain generalized syndrome. Pain Phys. 2011;14:E217-245.
- Dailey DL, Keffala VJ, Sluka KA. Do cognitive and physical fatigue tasks enhance pain, cognitive fatigue, and physical fatigue in people with fibromyalgia. Arthritis Care Res (Hoboken). 2015;67:288-296.