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rheumatoid arthritis Definition
Rheumatoid arthritis is an inflammation that can affect many joints, and even other systems of the body.
What is going on in the body?
Rheumatoid arthritis belongs to a group of diseases called "autoimmune" diseases. These diseases are characterised by an immune system that goes "out of control" and begins to attack the body itself.
The body's immune system produces antibodies, which are protein molecules that the body uses to fight infection. These antibodies are produced by the immune system in response to a trigger called an antigen. This trigger is normally a substance that the body recognises as "foreign". These foreign substances include things like bacteria and viruses.
In rheumatoid arthritis, for reasons unknown, the body's immune system malfunctions and begins producing antibodies against its own tissues. This causes the body's own immune system to attack it's own joints, causing inflammation, swelling and pain.
Chronic inflammation of the lining of joints, or synovitis, causes certain tissue called pannus to form at the edge of the joint. This erodes the joint surface and leads to progressive arthritis. Rheumatoid arthritis usually begins between 30 and 40 years of age. It is three times more common in women than in men. Sometimes this form of arthritis is mild, but 70% of people who have it develop chronic problems, and 15% have severe crippling disease. Young children can have a form called juvenile rheumatoid arthritis.
What are the signs and symptoms of the disease?
Joint pain, swelling, and stiffness, especially severe and prolonged in the morning, are the most common symptoms. The problems may migrate from one joint to another. The most common presentation is symmetrical chronic polyarthritis, that is if one side of the body is involved, the corresponding joint on the other side will become involved too. Multiple joints are usually affected at the same time. Deformities can result, such as misshapen fingers, bunion or hammer toes, and knock-knees. The affected joints are swollen and warm. Bumps called rheumatoid nodules can occur on the back of the elbow under the skin. The rheumatoid process can also involve the eye, known as episcleritis, and the lungs, known as interstitial disease.
What are the causes and risks of the disease?
Many factors contribute to the disease, which is not yet fully understood. It is speculated that some type of infection or injury may so alter the immune system that the body begins to react against its own organs and tissues, notably the joints.
What can be done to prevent the disease?
Rheumatoid arthritis cannot be prevented.
How is the disease diagnosed?
The diagnosis is made by observing the person and the pattern of the disease. A blood test for the rheumatoid factor is positive in 75% to 90 % of cases but is not diagnostic. Rheumatoid arthritis with a normal rheumatoid factor is called seronegative. X-rays can show osteopenia, or thin bones, around the affected joints, and narrowing of the joint space. Erosions that look on x-ray like bites out of the bone are common, even with in a few months of the disease onset. The bone spurs or osteophytes characteristic of osteoarthritis are not seen. It is important to rule out other diseases, such as systemic lupus erythematosus.
What are the long-term effects of the disease?
The arthritis may be progressive and affect many joints. This can make walking very difficult and interfere greatly with the function of the hands. Disability may be severe. Foot deformities may require special shoes. Other organs can be affected by this multi-system disease. The inflammation of blood vessels or the lining around the heart, known as vasculitis or pericarditis, can result.
What are the treatments for the disease?
There are several approaches to treatment. Usually the first is medical, and the last is surgical. Aspirin or non-steroidal anti-inflammatory drugs, or NSAIDs, such as ibuprofen and naproxen are usually used. The newer COX-2 specific inhibitor NSAIDs such as celecoxib and rofecoxib are safer on the gastrointestinal tract for those patients who are at risk to develop NSAID-induced peptic ulcers.
Corticosteroids, such as prednisone, can be taken in pill or by injection into the joint. Medications such as hydroxychloroquine, methotrexate, sulphasalazine, and gold such as aurothioglucose or auranofin are used to modify the disease. Low doses of methotrexate, a drug which is also used in much higher doses to treat certain cancers, is still the cornerstone of therapy of rheumatoid arthritis.
Other therapies used sometimes include azathioprine, cyclosporin, and cyclophosphamide, which may be effective but have potentially dangerous side effects. A new agent has recently been made available through the Pharmaceutical Benefits Scheme (PBS). Leflunomide, given once as a daily tablet.
Splints can help to rest a joint that is acutely inflamed. Exercise is important to maintain joint flexibility, strengthen weakened muscles, and promote conditioning. Rheumatoid patients who exercise feel better than those who do not.
Rehabilitation is critical for patients who have difficulty with a manual function and walking. Surgery may be needed to remove chronically inflamed joint linings, which is called synovectomy, or to replace the destroyed joint surfaces, known as total joint replacement.
Physicians who care for patients with rheumatoid arthritis are sensitive to their patient's psychological needs and respond by listening, reassurance, touching, and empowering patients to take control of their disease as best as possible. Patients with painful or advanced rheumatoid arthritis often need help in home, workplace, and social situations.
What are the side effects of the treatments?
NSAIDs may cause problems in the stomach, liver, blood, or kidneys. The use of corticosteroids may contribute to thinning of the bones, called osteoporosis, or death of the bone, called osteonecrosis, which especially may affect the head of the femur in the hip joint. Other drugs may cause other side effects so patients must be monitored closely.
Injection and surgery both carry a risk of infection, however small. If the neck is weak, intubation during anaesthesia for surgery of any kind may lead to spinal cord injury.
How is the disease monitored?
The amount of pain, swelling, and stiffness in joints is noted to gauge the response to treatment. Outcomes such as the ability to function in desired activities of daily living are observed. Regular eye examinations are important for patients taking hydroxychloroquine. Most of the drugs used require blood test monitoring.
Author: John A.K. Davies, MD
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Contributors
Potential conflict of interest information for reviewers available on request |
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