Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder that causes the immune system to attack the joints, where it causes inflammation (arthritis) and destruction. It can also damage some organs, such as the lungs and skin. It can be a disabling and painful condition, which can lead to substantial loss of functioning and mobility. It is diagnosed with blood tests (especially a test called rheumatoid factor) and X-rays. Diagnosis and long-term management are typically performed by a rheumatologist, an expert in the diseases of joints and connective tissues.

Various treatments are available. Non-pharmacological treatment includes physical therapy and occupational therapy. Analgesia (painkillers) and anti-inflammatory drugs, as well as steroids, are used to suppress the symptoms, while disease-modifying antirheumatic drugs (DMARDs) are often required to reverse the disease process and prevent long-term damage. In recent times, the newer group of biologics has increased treatment options.

The name is based on the term "rheumatic fever", an illness which includes joint pain and is derived from the Greek word rheumatos ("flowing"). The suffix -oid ("resembling") gives the translation as joint inflammation that resembles rheumatic fever. The first recognized description of rheumatoid arthritis was made in 1800 by Dr Augustin Jacob Landré-Beauvais (1772-1840) of Paris.

Signs and symptoms

While rheumatoid arthritis primarily affects joints, problems involving all other organs of the body are known to occur. Extra-articular ("outside the joints") manifestations occur in about 15% of individuals with rheumatoid arthritis. It can be difficult to determine whether disease manifestations are directly caused by the rheumatoid process itself, or from side effects of the medications commonly used to treat it - for example, lung fibrosis from methotrexate, or osteoporosis from corticosteroids.

Joints

The arthritis of rheumatoid arthritis is due to synovitis, which is inflammation of the synovial membrane that covers the joint. Joints become red, swollen, tender and warm, and stiffness prevents their use. By definition, RA affects multiple joints (it is a polyarthritis). Most commonly, small joints of the hands, feet and cervical spine are affected, but larger joints like the shoulder and knee can also be involved, differing per individual. Eventually, synovitis leads to erosion of the joint surface, causing deformity and loss of function.

Inflammation in the joints manifests itself as a soft, "doughy" swelling, causing pain and tenderness to palpation and movement, a sensation of localized warmth, and restricted movement. Increased stiffness upon waking is often a prominent feature and may last for more than an hour. These signs help distinguish rheumatoid from non-inflammatory diseases of the joints such as osteoarthritis (sometimes referred to as the "wear-and-tear" of the joints). In RA, the joints are usually affected in a fairly symmetrical fashion although the initial presentation may be asymmetrical.