Assessment of fibromyalgia

Wolfe, 2016Wolfe, 2011Wolfe, 2010

Pain in fibromyalgia is typically widespread and may be experienced in soft tissues and joints. While pain severity often fluctuates, it rarely follows the consistent diurnal pattern seen in inflammatory disorders. Patients may present with regionalised pain related to a recent event, but detailed questioning often reveals a more extensive pain history. Some individuals may be genetically predisposed to widespread pain, and a history of ‘growing pains’ or other painful disorders in childhood is not uncommon.

In addition to pain patients typically experience other symptoms, including cognitive clouding and impaired concentration (known as ‘fibrofog’), fatigue, sleep dysfunction, depression, and gastrointestinal and urogenital dysfunction and discomfort (irritable bowel and irritable bladder). Sleep dysfunction may be both a consequence of widespread pain and a perpetuating factor. Practitioner time and patience are required to evaluate symptoms in the context of the patient’s life-course and sociocultural setting.

A thorough physical and musculoskeletal examination should be performed. Although there are no physical examination findings specific to fibromyalgia, soft-tissue tenderness to pressure is typically diffuse. While the location and severity of tenderness varies between patients, some anatomical locations are tender in most patients with fibromyalgia (eg lateral epicondyles, trapezius muscles, anserine bursae). The presence of allodynia (pain induced by normal touch) should be sought in both history and examination; pain induced by inflation of a sphygmomanometer cuff is a useful screening tool. Dermographism is seen in some patients. Joint hypermobility is also common and may contribute to the overall disease experience, but is rarely an indicator of a serious heritable collagen disorder.

The diagnosis can be supported by diagnostic criteria that incorporate widespread pain and other symptoms typical of fibromyalgia, such as the American College of Rheumatology (ACR) diagnostic criteria. Importantly, a formal tender point count is not required. However, these criteria do not replace clinical judgement in the diagnosis of fibromyalgia. When considering the diagnosis, practitioners should recognise that fibromyalgia symptoms exist on a spectrum and may vary within an individual over time.

Since fibromyalgia frequently coexists with other rheumatological diseases, a complete clinical evaluation of a patient with musculoskeletal pain should seek evidence of joint inflammation and other signs of inflammatory rheumatic diseases.

Laboratory or imaging investigations are often not required in patients who present with a typical clinical picture of fibromyalgia without symptoms or signs suggesting an alternative or coexistent diagnosis. Undertaking investigations for alternative diagnoses that are unlikely risks overdiagnosis or false-positive findings, which can cause the patient distress.

Any change in the nature or pattern of symptoms needs another thorough clinical assessment to avoid missing the onset of a comorbid illness.

Consider referral to a rheumatologist if the diagnosis is uncertain or the patient’s presentation is atypical (see When to refer a patient with fibromyalgia to a specialist).