Fibromyalgia (2012 Canadian Guidelines)

Rational

Fibromyalgia was first identified as a clinical syndrome in 1990 by the American College of Rheumatology.  Neurophysiologic evidence of pain dysregulation may be one of the central issues, though the syndrome is complex and diverse in presentation.

Epidemiology

Affects 2-3% of the population with a predominance of women in their 3rd to 5th decades.  Women affected 6-9 times more frequency than men.

Screening

Not done.

Diagnostic Criteria

Clinical diagnosis, not one of exclusion, does not require specialist confirmation, and requires very little laboratory testing.  Tender point examination is no longer recommended for diagnosis.

Pivotal Sx is pain, but non-restorative sleep, cognitive decline, mood disorder, and variable somatic Sx may also be present.

Pain: must be present for at least 3 months, usually beginning in one location and then generalizing.  The pain can vary in intensity and location from day-to-day, and is affected by factors such as stress or weather.

Risk Factors

Sexual abuse, depression/mood disorders, female 30-50 years old, disability/unemployment

Investigations

PEx with palpation of the soft tissues.  Tenderness in the soft tissues with no object findings to explain the tenderness is consistent with a diagnosis of fibromyalgia.  The physical exam involving the old 18 tender points, with a requisite 11 or more for the diagnosis of fibromyalgia has been eliminated in the 2010 guidelines because it has no practical utility.

Recommended screening BW to R/O other disorders: CBC, ESR, CRP, TSH, CK

Consider sleep study and psych referral where appropriate.

Management

Patients suffering from fibromyalgia are often frustrated by the lack of tangible physical finding to correlate with their Sx.  The empathy and understanding of their suffering by a primary care physician can be instrumental in forming a therapeutic alliance.

Follow patient change with the PGIC score.  There are other scoring systems for fibromyalgia such as the Fibromyalgia Impact Questionnaire (FIG) and the revised score (FIGR), but the clinical utility of these time-consuming questionnaires is unclear.

Encourage patient to remain in the workforce, as it tends to be associated with better outcomes.

Treatment

Non-pharmacologic: education, exercise therapy, CBT, and multidisciplinary therapy.

Focus on coping skills and self management

Pharmacologic Rx: initially start with tylenol and/or NSAIDs prn.  Tramadol can be considered.  Other opioids must be utlized only in the appropriate setting and monitored very carefully; avoiding these medications is ideal, as they can exacerbate other Sx of fibromyalgia.  Nabilone can be used, and may be particularly helpful if a sleep disturbance is present.  If this is not sufficient, TCAs, SSRIs, or SNRIs can be tried.  It should be explained to the patient that these medications have a pain modulation effect, and thus the therapy is not directed towards mood.  In a similar way, anticonvulsant medications can also be tried, such as gabapentin or pregabalin.

Note: currently only pregabalin and duloxetine have Health Canada approval for fibromyalgia, and all other medications are off-label use.

Prognosis

Difficult to predict.  Shorter course of disease increases the chance of resolution, whereas chronic Sx tend to resolve less well.

References

2012 Canadian Guidelines for the diagnosis and management of fibromyalgia syndrome. Fitzcharles et al. Guidelines from the Canadian Pain Society and the Canadian Rheumatology Association. 2012.