Fibromyalgia: State-of-the-Art Overview

Ernest H. Choy
CREATE Centre, Section of Rheumatology, Division of Infection and Immunity, Cardiff University, United Kingdom

Fibromyalgia (FM) as a clinical diagnosis was brought about by the 1990 American College of Rheumatology (ACR) classification criteria [1]. Although these were developed initially to facilitate research, it gained widespread acceptance as a diagnostic tool. However, pain is a subjective symptom. The lack of specific pathology or diagnostic test, as well as the association with depression or anxiety, led many to question the legitimacy of FM as a medical illness. Over the last decade, there is a significant shift in the increasing acceptance of FM among Rheumatology community, driven by the recognition that improving the diagnosis and management of chronic pain in musculoskeletal diseases is a major unmet medical need.

First, FM is common. Prevalence of fibromyalgia in the general population is 2% [2]. A UK study found that the incidence of FM increased from 33.3 in 2001 to 38.2 per 100,000 people in 2013 [3]. The healthcare and societal burden associated with FM is high [4]. Delay in diagnosis led to inappropriate investigations and referrals to multiple specialties [5].

With functional neuroimaging, objective evidence of abnormal pain processing has been consistently demonstrated [6] removing the stigma of pain in FM being psychogenic. Furthermore, whilst FM cannot be cured, systematic reviews based national and international guidelines such as European League Against Rheumatism (2016), Canadian Pain Society and Canadian Rheumatology Association (2012), as well as the Association of the Scientific Medical Societies in Germany (2012),  agreed on the overall approach to FM should be multi-modal approach using non-pharmacological and with necessary pharmacological treatments to reduce pain and improve function [7-9]. Exercise and psychological/mind-body therapies are recommended by guidelines. If the response to non-pharmacological treatments is inadequate, low dose amitriptyline, serotonin-noradrenalin reuptake inhibitors (duloxetine, milnacipran) and the anti-convulsant, pregabalin may be added.  The approval of duloxetine, milnacipran, and pregabalin by the Food and Drug Administration for the treatment of FM further emphasized FM being a treatable condition.

The ACR 2010 provisional criteria for FM [10], which has been updated in 2011 and 2016, allowed FM to be diagnosed by using questionnaire. One of the major advantages of these provisional criteria is that the diagnosis of FM can be made by primary care physician and the first-line treatment be initiated without referral to secondary care. Such an approach was recommended by the Canadian guidelines [8]. This may avoid delay in diagnosis and reduce unnecessary investigations and referral to secondary care.

More recently, comorbid FM is increasingly recognized in many chronic musculoskeletal diseases. Patients with comorbid FM have higher diseases activity score and more severe pain. Disease activity scores used in "treat-to-target" guidelines are higher in these patients. The management of these patients with comorbid FM poses an important challenge for Rheumatologists. 

References

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