Appendix A: Medical Aspects of Fibromyalgia


Fibromyalgia is a chronic disorder that presents with diffuse musculoskeletal pain. It frequently presents with tender points, fatigue, non-restorative sleep, and disturbed cognitive function. Mood disorders such as depressive disorders, functional GI conditions such as irritable bowel syndrome, and multiple somatic complaints such as paresthesia, headaches, and interstitial cystitis present as comorbidities with fibromyalgia. The etiology of this condition is not clear, but research suggests that this condition may be caused by pain dysregulation and may be a form of pain centralization.

The prevalence of fibromyalgia in the United States and other countries ranges between 2-3% with a significantly higher prevalence in women and an increased prevalence in older individuals. The condition is 6 times more common in women evaluated in specialty clinics but the prevalence difference between males and females is lower when using survey criteria that do not consist of examinations for tender points.

Initial treatment of fibromyalgia is to address the main symptoms of this condition: pain, fatigue, insomnia and non-restorative sleep, and cognitive dysfunction. Some patients may only require non-pharmacologic treatments especially if no comorbid mood or sleep disorder exists. Patient education should be used as the initial step in treatment of fibromyalgia.1 Non-pharmacologic treatment includes patient education and an exercise program.2

According to Goldenberg et al.,3 patient education should include:

  • Fibromyalgia is a real and recognized condition and not imagined1,3;
  • Explanation that fibromyalgia is a centralized pain disorder with no organic or peripheral cause and no structural or visceral pathology1-3;
  • Explanation that there is no evidence that fibromyalgia is related to any persistent infection3;
  • Discussion on how stress and mood disturbances factor into the condition of fibromyalgia and what can be done to mitigate the stress and mood disturbances2-3;
  • Education about sleep disorders and sleep hygiene2-3;
  • Discussion on the importance of exercise for maintaining functional capacity and that excessive sedentary activity is a major risk factor for fibromyalgia3;
  • Discussion that even though the symptoms will wax and wane, and persist, most fibromyalgia patients live normal and active lives1,3; and
  • Education about maladaptive chronic illness behavior.3

Exercise can improve both pain and function and may help with sleep quality. The 2017 revised European League Against Rheumatism (EULAR) report considers exercise to have a high efficacy such that it is the only “strong” therapy recommendation for fibromyalgia.4 Exercise programs should consist of low-impact cardiovascular aerobic activities such as fast walking, cycling, swimming and water aerobics (land or aquatic are equally effective),5 and resistance exercise training.6

For patients who do not acquire adequate control of their fibromyalgia with patient education and exercise, the next step would be pharmacologic treatments. First-line medications consist of low-dose tricyclic antidepressants, or cyclobenzaprine as an alternative to tricyclic antidepressants. If the patient has severe fatigue or depression, a serotonin-norepinephrine reuptake inhibitor (SNRI) can be used instead of a tricyclic antidepressant. For patients with severe sleep disturbances, an alpha2-ligand anticonvulsant including pregabalin and gabapentin can also be used as initial pharmacotherapy instead of a tricyclic antidepressant. FDA has approved pregabalin, duloxetine, and milnacipran for the treatment of fibromyalgia.2 Analgesics such as acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids have not been shown to be of benefit in the treatment of fibromyalgia. Furthermore, opioid use might be associated with increased harm to include increased impairment.7,8 Comorbid conditions such as irritable bowel syndrome may also require medications.

Many fibromyalgia patients have persistent symptoms despite initial non-pharmacologic treatment and single drug therapy at maximum doses. Depending on the symptoms, combination drug therapy might be indicated. Subspecialty consultation such as rheumatology, physiatry, psychiatry, psychology, or pain management might also be indicated for further management of the fibromyalgia.

Fibromyalgia patients have a higher prevalence of disability compared to the general population. In North America, fibromyalgia patients under the age of 65 years were on average ten times more likely to state they were unable to work due to health conditions compared to those without fibromyalgia, filed for Social Security disability 9 to 10 times more often than those without fibromyalgia, and received disability payments ten times more often compared to those without fibromyalgia.9

Various diagnostic and classification criteria have been developed for fibromyalgia. However, most criteria have been useful for clinical research and epidemiologic studies and have not been validated for individual patient diagnosis. The clinician’s clinical experience and the clinical encounter especially the history and physical are key in getting an accurate diagnosis. The two criteria commonly used in the diagnosis of fibromyalgia are the 2010 American College of Rheumatology preliminary diagnostic criteria,10 and the 2019 Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks (ACTTION) American Pain Society (APS) Pain Taxonomy (AAPT) Diagnostic Criteria.11 See the table below comparing and contrasting the criteria from the two professional societies.

Comparisons between ACR and AAPT Diagnostic Criteria

Criteria ACR 2010 AAPT
Pain Widespread pain index (WPI) >7 and symptom severity (SS) scale score >5 or WPI 3-6 and SS scale score >9. WPI score is between 0 and 19. There are 19 possible areas that the patient can have pain over the past week. Multisite Pain (MSP) at 6 or more pain from total of 9 possible body sites.^^
Presence of other disorders SS scale score^ for fatigue, waking unrefreshed, cognitive symptoms, somatic symptoms.* See Pain Criterion for scoring cutoffs. Moderate to severe sleep problems OR fatigue.
Duration of symptoms Symptoms have been present at a similar level for at least 3 months. MSP plus fatigue or sleep problems present for at least 3 months.
Presence of other disorders Does not have a disorder that would otherwise explain the pain. Presence of another pain disorder or related symptoms does not rule out a diagnosis of FM. A clinical assessment should be done to evaluate for any condition that could fully explain the patient’s symptoms or contribute to the severity of the symptoms.
*Somatic symptoms may consist of muscle pain, irritable bowel syndrome, fatigue/tiredness, thinking or remembering problem, muscle weakness, headache, abdominal pain/cramps, numbness/tingling, dizziness, insomnia, depression, constipation, upper abdominal pain, nausea, nervousness, chest pain, blurred vision, fever, diarrhea, dry mouth, itching, wheezing, Raynaud’s phenomenon, hives/welts, tinnitus, vomiting, heartburn, oral ulcers, loss of/change in taste, seizures, dry eyes, shortness of breath, loss of appetite, rash, sun sensitivity, hearing difficulties, easy bruising, hair loss, frequent urination, painful urination, and bladder spasms.
^SS scale score – for each of the first 3 symptoms listed above (fatigue, waking unrefreshed, and cognitive symptoms), use the following scale:
0 = no problem; 1 = slight or mild problems generally mild or intermittent; 2 = moderate, considerable problems, often present and/or at a moderate level; 3 = severe, pervasive, continuous life-disturbing problems. For somatic symptoms in general, score as follows: 0 = no symptoms; 1 = few symptoms; 2 = moderate number of symptoms; 3 = great deal of symptoms.
The SS scale score is the sum of the severity of the three symptoms (fatigue, waking unrefreshed, cognitive symptoms) plus the extent (severity of somatic symptoms in general. Final score is between 0 and 12.10
^^The body sites consist of the following areas: head, left arm, right arm, chest, abdomen, upper back and spine, lower back and spine including buttocks, left leg, and right leg.11