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.
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.
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.
As the pathology progresses the inflammatory activity leads to erosion and destruction of the joint surface, which impairs their range of movement and leads to deformity. The fingers are typically deviated towards the little finger (ulnar deviation) and can assume unnatural shapes. Common deformities in rheumatoid arthritis are the Boutonniere deformity (Hyperflexion at the proximal interphalangeal joint with hyperextension at the distal interphalangeal joint), swan neck deformity (Hyperextension at the proximal interphalangeal joint, hyperflexion at the distal interphalangeal joint). The thumb may develop a "Z-thumb" deformity with fixed flexion and subluxation at the metacarpophalangeal joint, and hyperextension at the IP joint.
The rheumatoid nodule is the cutaneous (strictly speaking subcutaneous) feature most characteristic of rheumatoid arthritis. The initial pathologic process in nodule formation is unknown but is thought to be related to small-vessel inflammation. The mature lesion(a part of an organ or tissue which has been damaged) is defined by an area of central necrosis surrounded by palisading macrophages and fibroblasts and a cuff of cellular connective tissue and chronic inflammatory cells. 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 olecranon, the calcaneal tuberosity, the metacarpophalangeal joints, or other areas that sustain repeated mechanical stress. Nodules are associated with a positive RF titer and severe erosive arthritis. Rarely, they can occur in internal organs.
Several forms of vasculitis are also cutaneous manifestations associated with rheumatoid arthritis. 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 due to the presence of an obliterative cutaneous capillaropathy.
Other, rather rare, skin associated symtoms include:
Fibrosis of the lungs is a recognised response to rheumatoid disease. It is also a rare but well recognised consequence of therapy (for example with methotrexate and leflunomide). Caplan's syndrome describes lung nodules in individuals with rheumatoid arthritis and additional exposure to coal dust. Pleural effusions are also associated with rheumatoid arthritis.
Renal amyloidosis can occur as a consequence of chronic inflammation. Rheumatoid vasculitis is a rare cause of glomerular disease in the kidney. Treatment with Penicillamine and gold salts are recognized causes of membranous nephropathy.
People with rheumatoid arthritis are more prone to atherosclerosis, and risk of myocardial infarction (heart attack) and stroke is markedly increased. Other possible complications that may arise include: pericarditis, endocarditis, left ventricular failure, valvulitis and fibrosis.
Ocular
keratoconjunctivitis sicca (dry eyes), scleritis, episcleritis and scleromalacia.
Gastrointestinal and hematological
Felty syndrome, anemia, thrombocytosis.
Neurological
peripheral neuropathy and mononeuritis multiplex may occur. The most common problem is carpal tunnel syndrome due to compression of the median nerve by swelling around the wrist. Atlanto-axial subluxation can occur, owing to erosion of the odontoid process and or/transverse ligaments in the cervical spine's connection to the skull. Such an erosion (>3mm) can give rise to vertebrae slipping over one another and compressing the spinal cord. Clumsiness is initially experienced, but without due care this can progress to quadriplegia.
Constitutional symptoms
Constitutional symptoms including fatigue, low grade fever, malaise, morning stiffness, loss of appetite and loss of weight are common systemic manifestations seen in patients with active rheumatoid arthritis.
Vasculitis
Vasculitis in rheumatoid arthritis is common. It typically presents as vasculitic nailfold infarcts.
Osteoporosis
Osteoporosis classically occurs in RA around inflamed joints. It is postulated to be partially caused by inflammatory cytokines.
Lymphoma
The incidence of lymphoma is increased in RA as it is in most autoimmune conditions.
The American College of Rheumatology has defined (1987) the following criteria for the classification of rheumatoid arthritis:
At least four criteria have to be met for classification as RA. These criteria are not intended for the diagnosis for routine clinical care; they were primarily intended to categorize research. For example: one of the criteria is the presence of bone erosion on X-Ray. Prevention of bone erosion is one of the main aims of treatment because it is generally irreversible. To wait until all of the ACR criteria for rheumatoid arthritis are met may sometimes result in a worse outcome. Most sufferers and rheumatologists would agree that it would be better to treat the condition as early as possible and prevent bone erosion from occurring, even if this means treating people who don't fulfill the ACR criteria. The ACR criteria are, however, very useful for categorising established rheumatoid arthritis, for example for epidemiological purposes.
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