The synovium also forms a sheath for certain tendons of the hands and feet.
The membrane secretes synovial fluid, which lubricates the joint or tendon.
The synovium can become inflamed; in a joint this is known as synovitis, in a tendon sheath it is known as tenosynovitis.
Causes There is a major immunogenetic predisposition to rheumatoid arthritis in people carrying the HLA-DR4 antigen (see HLA SYSTEM). Other minor immunogenetic factors have also been implicated. In addition, there is a degree of familial clustering which suggests other unidenti?ed genetic factors. Genetic factors cannot alone explain aetiology, and environmental and chance factors must be important, but these have yet to be identi?ed.
Epidemiology Rheumatoid arthritis more commonly occurs in women from the age of 30 onwards, the sex ratio being approximately 4:1. Typical rheumatoid arthritis may occur in adolescence, but in childhood chronic SYNOVITIS usually takes one of a number of di?erent patterns, classi?ed under juvenile chronic arthritis.
Pathology The primary lesion is an in?ammation of the synovial membrane of joints. The synovial ?uid becomes diluted with in?ammatory exudate: if this persists for months it leads to progressive destruction of articular CARTILAGE and BONE. Cartilage is replaced by in?ammatory tissue known as pannus; a similar tissue invades bone to form erosions. Synovitis also affects tendon sheaths, and may lead to adhesion ?brosis or attrition and rupture of tendons. Subcutaneous and other bursae may be involved. Necrobiotic nodules also occur at sites outside synovium, including the subcutaneous tissues, the lungs, the pericardium and the pleura.
Clinical features Rheumatoid arthritis varies from the very mild to the severely disabling. Many mild cases probably go undiagnosed. At least 50 per cent of patients continue to lead a reasonably normal life; around 25 per cent are signi?cantly disabled in terms of work and leisure activities; and a minority become markedly disabled and are limited in their independence. There is often an early acute phase, followed by substantial remission, but in other patients gradual step-wise deterioration may occur, with progressive involvement of an increasing number of joints.
The diagnosis of rheumatoid arthritis is largely based on clinical symptoms and signs. Approximately 70 per cent of patients have rheumatoid factor ANTIBODIES in the SERUM but, because of the large number of false positives and false negatives, this test has very little value in clinical practice. It may be a useful pointer to a worse prognosis in early cases if the level is high. X-RAYS may help in diagnosing early cases and are particularly helpful when considering surgery or possible complications such as pathological fracture. Patients commonly develop ANAEMIA, which may be partly due to gastrointestinal blood loss from antiin?ammatory drug treatment (see below).
Treatment involves physical, pharmacological, and surgical measures, together with psychological and social support tailored to the individual patient’s needs. Regular activity should be maintained. Resting of certain joints such as the wrist with splints may be helpful at night or to assist prolonged manual activities. Sound footwear is important. Early use of antirheumatic drugs reduces long-term disability. Drug treatment includes simple ANALGESICS, NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS), and slow-acting drugs including GOLD SALTS (in the form of SODIUM AUROTHIOMALATE), PENICILLAMINE, SULFASALAZINE, METHOTREXATE and AZATHIOPRINE.
The non-steroidal agents are largely e?ective in reducing pain and early-morning sti?ness, and have no e?ect on the chronic in?ammatory process. It is important, especially in the elderly, to explain to patients the adverse effects of NSAIDs, the dosage of which can be cut by prescribing paracetamol at the same time. Combinations of anti-rheumatic drugs seem better than single agents. The slow-acting drugs take approximately three months to act but have a more global e?ect on chronic in?ammation, with a greater reduction in swelling and an associated fall in erythrocyte sedimentation rate (ESR) and rise in the level of HAEMOGLOBIN. Local CORTICOSTEROIDS are useful, given into individual joints. Systemic corticosteroids carry serious problems if continued long term, but may be useful under special circumstances. Much research is currently going on into the use of tumour necrosis factor antagonists such as INFLIXIMAB and etanercept, but their precise role remains uncertain.... rheumatoid arthritis
(See also lumbosacral spasm.)... lumbago
Pain and inflammation may be relieved by analgesic drugs, nonsteroidal anti-inflammatory drugs, and injections of corticosteroid drugs.
Swelling usually reduces with rest, firm bandaging, icepacks, and keeping the affected joint raised.
In some cases, the fluid is drawn out with a needle and syringe.... effusion, joint
joint The junction between 2 or more bones. Many joints are highly mobile, while others are fixed or allow only a small amount of movement.
Joints in the skull are fixed joints firmly secured by fibrous tissue. The bone surfaces of mobile joints are coated with smooth cartilage to reduce friction. The joint is sealed within a tough fibrous capsule lined with synovial membrane (see synovium), which produces a lubricating fluid. Each joint is surrounded by strong ligaments that support it and prevent excessive movement. Movement is controlled by muscles that are attached to bone by tendons on either side of the joint. Most mobile joints have at least one bursa nearby, which cushions a pressure point.
There are several types of mobile joint. The hinge joint is the simplest, allowing bending and straightening, as in the fingers. The knee and elbow joints are modified hinge joints that allow some rotation as well. Pivot joints, such as the joint between the 1st and 2nd vertebrae (see vertebra), allow rotation only. Ellipsoidal joints, such as the wrist, allow all types of movement except pivotal. Ball-and-socket joints include the hip and shoulder joints. These allow the widest range of movement (backwards or forwards, sideways, and rotation).
Common joint injuries include sprains, damage to the cartilage, torn ligaments, and tearing of the joint capsule.
Joint dislocation is usually caused by injury but is occasionally congenital.
A less severe injury may cause subluxation (partial dislocation).
Rarely, the bone ends are fractured, which may cause bleeding into the joint (haemarthrosis) or effusion (build-up of fluid in a joint) due to synovitis (inflammation of the joint lining).
Joints are commonly affected by arthritis.
Bursitis may occur as a result of local irritation or strain.... jogger’s nipple
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