Rheumatoid arthritis (RA) causes joint inflammation and pain. It happens when the immune system doesn’t work properly and attacks the lining of the joints (called the synovium). The disease commonly affects the hands, knees or ankles, and usually the same joint on both sides of the body. But sometimes, RA causes problems in other parts of the body as well, such as the eyes, heart and circulatory system and/or lungs. For unknown reasons, more women than men get RA, and it usually develops in middle age. Having a family member with RA increases the odds of developing RA.
In a healthy person, the immune system fights invaders, such as bacteria and viruses. With an autoimmune disease like RA, the immune system mistakes the body’s cells for foreign invaders and releases inflammatory chemicals that attack, in the case of RA, the synovium. The synovium is the tissue lining around a joint that produces a fluid to help the joint move smoothly. The inflamed synovium gets thicker and makes the joint area feel painful and tender, look red and swollen and moving the joint may be difficult.
Researchers aren’t sure why some people develop RA. They think that these individuals have certain genes that are activated by a trigger in the environment, like a virus or bacteria, or physical or emotional stress or some other external factor.
In the early stages, people with RA may not see redness or swelling in the joints, but they may experience tenderness and pain.
These symptoms are clues to RA:
- Joint pain, tenderness, swelling or stiffness that lasts for six weeks or longer.
- Morning stiffness that lasts for 30 minutes or longer.
- More than one joint is affected.
- Small joints (wrists, certain joints in the hands and feet) are typically affected first.
- The same joints on both sides of the body are affected.
- Many people with RA get very tired (fatigue) and some may have a low-grade fever. RA symptoms may come and go. Having a lot of inflammation and other symptoms is called a flare. A flare can last for days or months.