Rheumatoid arthritis causes pain and swelling in the joints, including the hands, feet and wrists.
As well as the joints, rheumatoid arthritis, sometimes called RA, can affect the skin, eyes, lungs, heart, blood, or nerves.
More women are affected by rheumatoid arthritis than men, with the condition being most common between 40 and 70. More than 400,000 people in the UK have rheumatoid arthritis.
What are the symptoms of rheumatoid arthritis?
Symptoms of rheumatoid arthritis include:
- Joint pain and swelling
- Stiffness, especially in the morning or after sitting for long periods
- Joint deformity
Rheumatoid arthritis affects everyone differently. For some, joint symptoms develop gradually over several years. In others, rheumatoid arthritis may progress rapidly, while other people may have rheumatoid arthritis for a limited period of time and then enter a period of remission.
What causes rheumatoid arthritis?
Rheumatoid arthritis is an autoimmune disease. With rheumatoid arthritis, something seems to trigger the immune system to attack the joints and sometimes other organs of the body. The exact cause of rheumatoid arthritis is unknown, but it is thought to be due to a combination of genetic, environmental, and hormonal factors. Some theories suggest that a virus or bacteria may alter the immune system, causing it to attack the joints. Other theories suggest that smoking may lead to the development of rheumatoid arthritis.
Research hasn't completely determined exactly what role genetics plays in rheumatoid arthritis. However, some people do seem to have a genetic, or inherited factor, that increases their chance of developing rheumatoid arthritis.
How does rheumatoid arthritis affect the body?
Once the immune system is triggered, immune cells migrate from the blood into the joints and joint-lining tissue, called synovium. There the immune cells produce inflammatory substances. The increased number of cells and inflammatory substances within the joint cause irritation, wearing down of cartilage (the cushioning material at the end of bones), and swelling and inflammation of the joint lining. Inflammation of the joint lining stimulates it to produce excessive joint fluid within the joint.
As the joint lining expands, it may invade into, or erode, the adjacent bone, resulting in bone damage that is referred to as erosions. All of these factors cause the joint to become very painful, swollen, and warm to the touch.
How is rheumatoid arthritis diagnosed?
The diagnosis of rheumatoid arthritis is based on a combination of factors, including:
- The specific location and symmetry of painful joints, especially the hand joints
- The presence of joint stiffness in the morning
- Presence of bumps and nodules under the skin ( rheumatoid nodules)
- Results of x-ray tests that suggest rheumatoid arthritis
- Positive results of a blood test called the rheumatoid factor
Most, but not all, people with rheumatoid arthritis have the rheumatoid-factor antibody in their blood. Rheumatoid factors are actually antibodies that bind other antibodies. Rheumatoid factor may sometimes be present in people who do not have rheumatoid arthritis. Other diseases can also cause the rheumatoid factor to be produced in the blood. Therefore, the diagnosis of rheumatoid arthritis is based on a combination of joint abnormalities as well as laboratory information and not just the presence of the rheumatoid factor in the blood.