What Causes Joint Damage in Rheumatoid Arthritis?
In rheumatoid arthritis (RA) your immune system attacks your joints and other tissue in your body causing pain and inflammation. Researchers aren't sure why your immune system attacks itself. But scientists are starting to better understand the processes that cause joint damage in RA.
A Faulty Immune System
Understanding what happens during the RA disease process requires some explanation of your immune system. Your immune system is a complex group of cells and substances. It is designed to fight off foreign invaders, such as viruses and bacteria, and protect your body. For various reasons, your immune system sometimes goes haywire and attacks healthy tissue. This is what happens in RA and other autoimmune diseases.
Immune cells called T cells (short for T lymphocytes) are some of the main players in your immune system. T cells react to possible threats and begin making substances called cytokines (pronounced “sīto-kīns”). Cytokines are messengers that tell other parts of your immune system to start working. It’s like sounding a red alert. This is a good when you have an infection because you want your body to get rid of the infection. However, in RA, your T cells are reacting to your own joint tissue. The rest of your immune system starts attacking and inflames your joints.
Scientists believe that some people are more prone to RA due to genetic and environmental factors. They think that something, such as an infection, triggers your immune system to start the disease. Once your immune system is activated, it won't stop fighting the perceived invader.
Understanding Joint Destruction
As your immune system gets going, its cells start invading the tissue surrounding your joints, called the synovium. Synovial tissue provides nutrients to your cartilage and makes a lubricating fluid to keep your joint operating smoothly. It’s normally a very thin membrane that contains small blood vessels. However, once immune cells invade, it thickens and starts growing extra blood vessels. These extra vessels leak fluid and more cells into your joint.
As your synovial tissue grows thicker, it causes problems inside your joint. It can invade your bone and wear away your bone tissue. Your abnormal synovial tissue also causes your cartilage to break down. All of this causes the symptoms of RA, including joint pain, stiffness, swelling, and decreased range-of-motion.
Your doctor can see some of these changes on X-rays. He or she may notice thinned cartilage, bone erosions, and enlarged synovial tissue.
Rheumatoid Arthritis Treatments
RA treatments are able to trick the immune system process so that it no longer receives the message to attack. Some of the treatments for RA block cytokines. Others block T cells. These types of treatments are called biologic response modifiers (BRMs), or RA biologics. Other treatments called disease-modifying anti-rheumatic drugs (DMARDs) target other parts of your immune system response. Often prescribed together, these treatments can stop or slow joint damage and prevent disability from RA.
There are also RA treatments aimed at the processes going on inside your joints. Corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and some DMARDs target the overgrowth of synovial tissue, joint swelling, and pain.
RA is a complex disease. There is currently no cure. But scientists are working hard to better understand the processes involved in RA in order to develop even better therapeutics and perhaps prevent the disease altogether.
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