Osteoarthritis is the result of the wear and tear on joints. Rheumatoid arthritis, on the other hand, occurs when the immune system goes haywire and begins attacking joint linings. Rheumatoid arthritis is a chronic inflammatory condition that also affects other tissue, but the joints are usually the most severely affected.
Here is what we know about the causes of rheumatoid arthritis.
Although doctors aren't sure of the exact cause of rheumatoid arthritis, it's thought that it may result from a combination of genetics and environmental triggers. Some researchers believe an infection with a bacteria or virus can trigger the development of rheumatoid arthritis in someone who's genetically susceptible. However, to date, no infection or organism has been found that could be said to be the cause.
As rheumatoid arthritis develops, some of the body's immune cells recognize one type of the person's own protein as a foreign intruder. The exact protein is unknown and may be one of any number of potential candidates. Some of them are produced in response to infection, such as a viral, bacterial, or fungal infection. Other possible proteins may have a genetic connection or stem from other causes.
Whatever the source, cells called lymphocytes react to this protein. The reaction then causes the release of cytokines, which are chemical messengers that trigger more inflammation and destruction. With rheumatoid arthritis, the main target of inflammation is the synovium, the thin membrane that lines the joints. The inflammation also spreads to other areas in the body ultimately causing not only joint damage, but also inflammation, chronic pain, fatigue, and loss of function.
There are many cytokines or inflammatory mediators, but the most important in rheumatoid arthritis are tumor necrosis factor (TNF) and interleukin-1. These cytokines are thought to trigger the process of joint damage in rheumatoid arthritis. Some treatments for rheumatoid arthritis block these cytokines, reducing inflammation and joint damage.
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