Rheumatic pain

Abstract

Rheumatic pain describes pain of the joints and their connective tissues which is commonly associated with osteoarthritis (OA), which is a degenerative disorder of the joints and rheumatoid arthritis (RA), which is a systemic inflammatory disease. Until relatively recently it was assumed that the patient's pain was solely derived from peripheral mechanisms in affected joints. However, evidence now shows that a poor relationship exists between radiographic evidence of joint damage and pain (Bedson and Croft in BMC Musculoskelet Disord 9:116, [12]) with many patients reporting pain that does not correspond with the extent of joint pathology and pain that occurs adjacent to or at sites without tissue damage (Kean et al. in Inflammopharmacology 12(1):3-31, [94]; Gwilym et al. in J Bone Joint Surg Br 90(3):280-287, [66]). Treating the problem surgically by replacing the damaged joint does not always alleviate pain (Wylde et al. in Pain 152(3):566-572, [186]) whilst in some patients sham surgery (placebo) does (Moseley et al. in N Engl J Med 347(2):81-88, [121]). The extent of the pain experienced by rheumatic pain patients can be highly variable and in some cases there may be pain and tenderness present over much of the body [chronic widespread pain or fibromyalgia (FM)] in association with other somatic symptom pain disorders. Before non-invasive neuroimaging was available neuroscientists had to rely on studies of patients with brain or spinal cord lesions, or patients responses during neurosurgical procedures to understand the neural basis of human pain perception. Functional brain neuroimaging comprises a number of non-invasive brain imaging techniques which have improved our understanding of the underlying mechanisms involved in acute and chronic pain and pain therapy. These techniques are now beginning to influence the development of future treatments for pain.