Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder that primarily affects joints.[1] It may result in deformed and painful joints, which can lead to loss of function. The disease may also have signs and symptoms in organs other than joints.

The cause of rheumatoid arthritis is not completely understood. The process involves inflammation and fibrosis of the capsule around the joints. It also affects the underlying bone and cartilage.[1] RA can produce diffuse inflammation in the lungs, the membrane around the heart, the membranes of the lung, and whites of the eye. It can also produce nodular lesions, most common within the skin. It is a clinical diagnosis made mostly on the basis of symptoms and physical examination. X-rays, laboratory testing, and synovial fluid analysis might help support a diagnosis or exclude other diseases with similar symptoms.[2]

Treatments include both medication and non-pharmacological measures - the goal being to control joint inflammation and prevent joint damage and disability. Non-pharmacological treatment includes physical therapy, splints and braces, occupational therapy and dietary changes but these do not stop the progression of joint destruction. Painkillers and anti-inflammatory drugs, including steroids, suppress symptoms, but do not stop the progression either. Disease-modifying antirheumatic drugs (DMARDs) may slow or halt the progress of the disease.[2] Biological DMARDS like anti-TNF agents are effective but usually avoided in persons with active disease or hypersensitivity to these agents.[3] They have been shown to decrease the number of tender or swollen joints and the pain and disability due to the disease but there is little data about side effects.[4]Alternative medicine is not supported by evidence.[5][6][7]

RA affects between 0.5 and 1% of adults in the developed world with between 5 and 50 per 100,000 people newly developing the condition each year.[8] Onset is most frequent during middle age, but people of any age can be affected.[9] In 2013 it resulted in 38,000 deaths up from 28,000 deaths in 1990.[10] The name is based on the term "rheumatic fever", an illness which includes joint pain and is derived from the Greek word -rheuma (nom.), -rheumatos (gen.) ("flow, current"). The suffix -oid ("resembling") gives the translation as joint inflammation that resembles rheumatic fever. The first recognized description of RA was made in 1800 by Dr. Augustin Jacob Landr-Beauvais (17721840) of Paris.[11]

RA primarily affects joints, however it also affects other organs in more than 1525% of individuals.[12]

Arthritis of joints involves inflammation of the synovial membrane. Joints become swollen, tender and warm, and stiffness limits their movement. With time, multiple joints are affected (it is a polyarthritis). Most commonly involved are the small joints of the hands, feet and cervical spine, but larger joints like the shoulder and knee can also be involved.[13]:1089 Synovitis can lead to tethering of tissue with loss of movement and erosion of the joint surface causing deformity and loss of function.[2]

RA typically manifests with signs of inflammation, with the affected joints being swollen, warm, painful and stiff, particularly early in the morning on waking or following prolonged inactivity. Increased stiffness early in the morning is often a prominent feature of the disease and typically lasts for more than an hour. Gentle movements may relieve symptoms in early stages of the disease. These signs help distinguish rheumatoid from non-inflammatory problems of the joints, often referred to as osteoarthritis or "wear-and-tear" arthritis. In arthritis of non-inflammatory causes, signs of inflammation and early morning stiffness are less prominent with stiffness typically less than one hour, and movements induce pain caused by mechanical arthritis.[14] The pain associated with RA is induced at the site of inflammation and classified as nociceptive as opposed to neuropathic.[15] The joints are often affected in a fairly symmetrical fashion, although this is not specific, and the initial presentation may be asymmetrical.[13]:1089

As the pathology progresses the inflammatory activity leads to tendon tethering and erosion and destruction of the joint surface, which impairs range of movement and leads to deformity. The fingers may suffer from almost any deformity depending on which joints are most involved. Specific deformities, which also occur in osteoarthritis, include ulnar deviation, boutonniere deformity, swan neck deformity and "Z-thumb." "Z-thumb" or "Z-deformity" consists of hyperextension of the interphalangeal joint, fixed flexion and subluxation of the metacarpophalangeal joint and gives a "Z" appearance to the thumb.[13]:1089 The hammer toe deformity may be seen. In the worst case, joints are known as arthritis mutilans due to the mutilating nature of the deformities.[1]

The rheumatoid nodule, which is sometimes cutaneous, is the feature most characteristic of RA. It is a type of inflammatory reaction known to pathologists as a "necrotizing granuloma". The initial pathologic process in nodule formation is unknown but may be essentially the same as the synovitis, since similar structural features occur in both. The nodule has a central area of fibrinoid necrosis that may be fissured and which corresponds to the fibrin-rich necrotic material found in and around an affected synovial space. Surrounding the necrosis is a layer of palisading macrophages and fibroblasts, corresponding to the intimal layer in synovium and a cuff of connective tissue containing clusters of lymphocytes and plasma cells, corresponding to the subintimal zone in synovitis. The typical rheumatoid nodule may be a few millimetres to a few centimetres in diameter and is usually found over bony prominences, such as the elbow, the heel, the knuckles, or other areas that sustain repeated mechanical stress. Nodules are associated with a positive RF (rheumatoid factor) titer and severe erosive arthritis. Rarely, these can occur in internal organs or at diverse sites on the body.[citation needed].

Several forms of vasculitis occur in RA. A benign form occurs as microinfarcts around the nailfolds. More severe forms include livedo reticularis, which is a network (reticulum) of erythematous to purplish discoloration of the skin caused by the presence of an obliterative cutaneous capillaropathy.[citation needed].

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Rheumatoid arthritis - Wikipedia, the free encyclopedia