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by EO Mag Staff

About Arthritis

Rheumatoid Arthritis

This is the most common type of inflammatory arthritis affecting about one in 100 people.

What Causes it?

Rheumatoid arthritis occurs when the body's defence mechanisms go into action when there's no threat and start attacking the joints and sometimes other parts of the body. It's not yet known why the immune system acts in this way in some people.

Who Gets it?

Rheumatoid arthritis is a common disease affecting about one in 100 people. People of all ages have the condition, but it most commonly starts between the ages of 30 and 50. Three times as many women are affected as men.

What Happens?

The joints become inflamed, particularly:

• the synovial membrane
• the tendon sheaths
• the bags of fluid that allow muscles and tendons to move smoothly over one another (bursae)

Inflammation sometimes becomes far worse - known as a 'flare-up' - when the joints become warm and red as blood flow to the area increases. The synovial membrane produces extra fluid, causing swelling and a stretching of the ligaments around the joint. The result is a stiff, swollen and painful joint.

In one in five cases, rheumatoid arthritis develops very rapidly but more often the symptoms develop over several months. The cycles of inflammation cause severe damage in many joints for about one in 20 people with the disease, but some have little or no damage. Treating inflammation as quickly as possible is vital because once joint damage has occurred, it can't be reversed.

What does it feel like?

Most people with rheumatoid arthritis get fluctuating pain and stiffness that gets worse during flare-ups. Whereas in osteoarthritis morning stiffness wears off quickly, it usually lasts more than 45 minutes in rheumatoid and other forms of inflammatory arthritis. Many people find that the condition gives them flu-like symptoms and makes them tired, irritable or depressed.

Does Arthritis run in families?

Arthritis doesn't run in families in the same way as, for example, blue eyes. In some forms of arthritis there's no genetic link at all. In others, genes may be one of several factors (such as hormones and environmental factors) that together cause the disease. For example, all people with a type of arthritis called ankylosing spondylitis (AS) have an inherited gene known as HLA B27 that makes them susceptible to the disease. But most people who have HLA B27 are free of AS. The gene alone isn't enough to cause the condition.

There is no single gene to blame for rheumatoid arthritis, and when one family member develops the disease the risk to others in the family is small. However, although about 0.5-1.0% of people in most populations will develop rheumatoid arthritis, it is much more common among the Pima Indians (5.3%) and the Chippewa Indians (6.8%) and far less common in China and Japan. This shows that genetics do play some part in predisposing to rheumatoid arthritis. The main risk comes from a group of genes known as the HLA DRB1 alleles, but several genes appear to be involved, each of which exerts only small effects to different degrees in different people.