Pain reported in multiple body sites is common. The term ‘widespread pain’ (which includes fibromyalgia) is used to describe pain that is present in left and right sides of the body and above and below the waist. The syndrome fibromyalgia is a more severe form of chronic widespread pain, in which patients also have additional somatic symptoms that have an impact on their functioning. In this chapter, we refer to widespread pain, but all points are applicable to fibromyalgia.

Widespread pain and fibromyalgia are not discrete disorders that can be easily separated from normal experience. Widespread pain is common: approximately 11% of the general population have symptoms whereas 2% have fibromyalgia. Symptoms are more frequently reported by women. Both widespread pain and fibromyalgia are more common with increasing age (until approximately the sixth decade) and at all ages symptoms are associated with poor mental health and reduced health-related quality of life. It is unclear why the prevalence of widespread pain decreases in the oldest old, however, changes in risk factors (psychological symptoms and work factors) and altered pain processing are possible explanations.

Several causal mechanisms have been identified in patients with widespread pain. These include, central pain processing, stress response, and genetic, psychosocial and work factors; however, the extent to which widespread pain symptoms can be attributed to a specific organic cause is limited.

Widespread pain is defined as pain in the axial skeleton and at least two quadrants of the body with pain on both right and left sides and above and below the waist. Chronic widespread pain requires symptoms to have been present for at least 3 months.

Most patients with widespread pain also experience other physical symptoms. They frequently present with other symptoms indicative of IBS and fatigue. Some patients with widespread pain are recognisable as frequent attenders and individuals with widespread pain have a poorer outcome than those with regional pain, which indicates the usefulness of asking about pain elsewhere in the body when a patient consults with regional pain. Body manikins or the Widespread Pain Index can be used to assess how widespread an individual’s pain is. Patients commonly have some degree of cognitive, mood and sleep problems; all of which should be taken into consideration when making decisions about clinical care, see Box 11.1.

A structured history should include current symptom, previous musculoskeletal pain and other somatic symptoms, the evolution of the problem (is it acute or chronic?) and any involvement of other systems. Consider getting the patient to complete the Widespread Pain Index or the Fibromyalgia Symptom Scale in order to get a standardised measure of severity.

The examination has two roles: to exclude other disorders and to demonstrate empathy to the patient and give them confidence that their problem is being taken seriously. A tender point examination and count is no longer required for a fibromyalgia diagnosis. A structured musculoskeletal examination, such as the GALS (gait, arms, legs, spine) screening examination, which is taught by UK undergraduate medical schools, and is published in detail in Arthritis Research UK’s student handbook (and accompanying DVD) on ‘Clinical Assessment of the Musculoskeletal System’, is a quick and useful way to assess the musculoskeletal system and exclude red flags. Further site-specific examinations should be carried out for any abnormalities observed. In addition to musculoskeletal examinations, a patient should be examined for other factors that may relate to a differential diagnosis, including those of concern that arose in the patient’s history and examining for skin rashes, psoriasis and signs of neurological problems.

A complete medical history and examination will help to determine what further investigations may be required. Box 11.2 lists recommended investigations for excluding other potential diagnostic explanations for the presenting pain.

Unless there is good clinical suspicion, vitamin D levels, rheumatoid factor and antinuclear antibody levels need not be tested. A small minority of patients may require referral for further investigations, as the clinician deems appropriate.

Explanations of a widespread pain disorder should acknowledge the patient’s pain, empathise with the impact that it has on their daily life and should be both realistic and reassure the patient that their symptoms are manageable.