Rheumatoid arthritis (RA) is an autoimmune disease in which the body’s immune system – which normally protects its health by attacking foreign substances like bacteria and viruses – mistakenly attacks the joints. This creates inflammation that causes the tissue that lines the inside of joints (the synovium) to thicken, resulting in swelling and pain in and around the joints. The synovium makes a fluid that lubricates joints and helps them move smoothly.
Rheumatoid arthritis most commonly affects the joints of the hands, feet, wrists, elbows, knees and ankles. The joint effect is usually symmetrical. That means if one knee or hand if affected, usually the other one is, too. Because RA also can affect body systems, such as the cardiovascular or respiratory systems, it is called a systemic disease. Systemic means “entire body.
Rheumatoid arthritis occurs when your immune system attacks the synovium — the lining of the membranes that surround your joints.
The resulting inflammation thickens the synovium, which can eventually destroy the cartilage and bone within the joint.
The tendons and ligaments that hold the joint together weaken and stretch. Gradually, the joint loses its shape and alignment.
Doctors don't know what starts this process, although a genetic component appears likely. While your genes don't actually cause rheumatoid arthritis, they can make you more susceptible to environmental factors — such as infection with certain viruses and bacteria — that may trigger the disease.
- Your sex. Women are more likely than men to develop rheumatoid arthritis.
- Age. Rheumatoid arthritis can occur at any age, but it most commonly begins in middle age.
- Family history. If a member of your family has rheumatoid arthritis, you may have an increased risk of the disease.
- Smoking. Cigarette smoking increases your risk of developing rheumatoid arthritis, particularly if you have a genetic predisposition for developing the disease. Smoking also appears to be associated with greater disease severity.
- Environmental exposures. Although poorly understood, some exposures such as asbestos or silica may increase the risk of developing rheumatoid arthritis. Emergency workers exposed to dust from the collapse of the World Trade Center are at higher risk of autoimmune diseases such as rheumatoid arthritis.
- Obesity. People — especially women age 55 and younger — who are overweight or obese appear to be at a somewhat higher risk of developing rheumatoid arthritis.
- Tender, warm, swollen joints
- Age. Rheumatoid arthritis can occur at any age, but it most commonly begins in middle age.
- Fatigue, fever and loss of appetite
Early rheumatoid arthritis tends to affect your smaller joints first — particularly the joints that attach your fingers to your hands and your toes to your feet.
As the disease progresses, symptoms often spread to the wrists, knees, ankles, elbows, hips and shoulders. In most cases, symptoms occur in the same joints on both sides of your body.
About 40 percent of the people who have rheumatoid arthritis also experience signs and symptoms that don't involve the joints. Rheumatoid arthritis can affect many nonjoint structures, including:
- Skin
- Eyes
- Lungs
- Heart
- Kidneys
- Salivary glands
- Nerve tissue
- Bone marrow
- Blood vessels
Rheumatoid arthritis signs and symptoms may vary in severity and may even come and go. Periods of increased disease activity, called flares, alternate with periods of relative remission — when the swelling and pain fade or disappear. Over time, rheumatoid arthritis can cause joints to deform and shift out of place.