Both osteoarthritis (OA) and rheumatoid arthritis (RA) involve pain and swelling in the joints, but there the similarity ends. The inflammation or swelling of rheumatoid arthritis is much more severe than the swelling that can occur in osteoarthritis.
With osteoarthritis, the basic problem is the breakdown of cartilage and sometimes bone. It can be so uncomfortable that the pain keeps you from moving your joint. The nearby muscles become weak because you aren’t exercising them enough, and the joint can “freeze up.” While osteoarthritis, unlike rheumatoid arthritis, won’t shorten your life, without proper care it may drastically limit your activity and change your lifestyle which of course can be pretty depressing. Fortunately, treatment can make an enormous difference.
Rheumatoid arthritis is a much more serious disease that must be treated promptly to avoid permanent damage. Untreated, it can damage your joints and lead to serious complications, even in other parts of your body. With this disease, your immune system, which normally protects your body and helps you recover from illnesses goes awry, attacking your joints and causing the membrane that lines them to swell and thicken.
Cartilage and bone may be destroyed, and in severe cases, the inflammation can affect the covering of the heart, small blood vessels, lungs, eyes, mouth, lymph glands, or spleen. As if this isn’t bad enough, the disease also can make you feel rotten. You may lose your appetite, hurt all over, run a fever, and feel tired all the time.
What exactly happens in rheumatoid arthritis? For reasons no one understands completely, your immune system causes your body to attack itself. Think about allergies: For some reason your body sees the allergen-mold or pollen or peanuts or whatever as a threat to the body. It kicks into full-scale battle mode, fighting an enemy that doesn’t exist.
Something similar happens in rheumatoid arthritis. Some researchers believe a virus or bacterium gets into your joint and triggers the process. Whatever the cause, your immune system, normally a well-tuned and helpful setup, kicks into attack mode. Special white blood cells band together to fight the infections or invaders such as bacteria.
These cells produce healing and infection fighting substances, which also happen to cause inflammation during the battle. When the battle is won and the wound is healed or the infection cured, normally your white blood cells calm down and the inflammation gradually goes away.
Unfortunately, in rheumatoid arthritis and other inflammatory diseases, there’s no “off” switch to tell your body the war is over. The protective cells are in battle mode with nothing to sound the all clear, so you end up with inflamed, swollen, painful joints.
In some people, not much happens besides the swelling that makes joints uncomfortable. In others, however, the disease gets worse. The membrane that lines the joint-the synovium-gets thick and rough. White blood cells gather and release enzymes that inflame the membrane and cause it to accumulate fluid. Sometimes the synovium starts to grow, even over the cartilage of the joint, and this growth in turn produces enzymes that erode the cartilage and bone.
For some people, without careful treatment rheumatoid arthritis can be crippling. Hands, feet, and arms may become not only stiff and painful, but also deformed. And rheumatoid arthritis can damage the lungs, heart, or eyes as well. Again, however, good medical treatment can forestall the worst damage in most cases.