Rheumatoid arthritis is an inflammatory disease that causes pain, swelling, stiffness, and loss of function in the joints. It has several special features that make it different from other kinds of arthritis. For example, rheumatoid arthritis generally occurs in a symmetrical pattern, meaning that if one knee or hand is involved, the other one also is. The disease often affects the wrist joints and the finger joints closest to the hand. It can also affect other parts of the body besides the joints. In addition, people with rheumatoid arthritis may have fatigue, occasional fevers, and a general sense of not feeling well.
 

Rheumatoid arthritis affects people differently. For some people, it lasts only a few months or a year or two and goes away without causing any noticeable damage. Other people have mild or moderate forms of the disease, with periods of worsening symptoms, called flares, and periods in which they feel better, called remissions. Still others have a severe form of the disease that is active most of the time, lasts for many years or a lifetime, and leads to serious joint damage and disability.

Features of Rheumatoid Arthritis

Tender, warm, swollen joints 
Symmetrical pattern of affected joints 
Joint inflammation often affecting the wrist and finger joints closest to the hand
Joint inflammation can affect other joints, including the shoulders,elbow,neck, hips, knees, ankles, and feet
Fatigue, occasional fevers, a general sense of not feeling well 
Pain and stiffness lasting for more than 30 minutes in the morning or after a long rest
Symptoms that last for many years

Variability of symptoms among people with the disease

Although rheumatoid arthritis can have serious effects on a person's life and well-being, current treatment strategies--including pain-relieving drugs and medications that slow joint damage, a balance between rest and exercise, and patient education and support programs--allow most people with the disease to lead active and productive lives. In recent years, research has led to a new understanding of rheumatoid arthritis and has increased the likelihood that, in time, researchers will find even better ways to treat the disease. Unlike osteoarthritis, rheumatoid arthritis affects a broader range of people.

How Rheumatoid Arthritis Develops and Progresses

The Joints
A joint is a place where two bones meet. The ends of the bones are covered by cartilage, which allows for easy movement of the two bones. The joint is surrounded by a capsule that protects and supports it. The joint capsule is lined with a type of tissue called synovium, which produces synovial fluid, a clear substance that lubricates and nourishes the cartilage and bones inside the joint capsule.

Like many other rheumatic diseases, rheumatoid arthritis is an autoimmune disease (auto means self), so-called because a person's immune system, which normally helps protect the body from infection and disease, attacks joint tissues for unknown reasons. White blood cells, the agents of the immune system, travel to the synovium and cause inflammation (synovitis), characterized by warmth, redness, swelling, and pain--typical symptoms of rheumatoid arthritis. During the inflammation process, the normally thin synovium becomes thick and makes the joint swollen and puffy to the touch.

A joint (the place where two bones meet) is surrounded by a capsule that protects and supports it. The joint capsule is lined with a type of tissue called synovium, which produces synovial fluid that lubricates and nourishes joint tissues. In rheumatoid arthritis, the synovium becomes inflamed, causing warmth, redness, swelling, and pain. As the disease progresses, the inflamed synovium invades and damages the cartilage and bone of the joint. Surrounding muscles, ligaments, and tendons become weakened. Rheumatoid arthritis also can cause more generalized bone loss that may lead to osteoporosis (fragile bones that are prone to fracture).

As rheumatoid arthritis progresses, the inflamed synovium invades and destroys the cartilage and bone within the joint. The surrounding muscles, ligaments, and tendons that support and stabilize the joint become weak and unable to work normally. These effects lead to the pain and joint damage often seen in rheumatoid arthritis. Researchers studying rheumatoid arthritis now believe that it begins to damage bones during the first year or two that a person has the disease, one reason why early diagnosis and treatment are so important.

Other Parts of the Body

Some people with rheumatoid arthritis also have symptoms in places other than their joints. Many people with rheumatoid arthritis develop anemia, or a decrease in the production of red blood cells. Other effects that occur less often include neck pain and dry eyes and mouth. Very rarely, people may have inflammation of the blood vessels, the lining of the lungs, or the sac enclosing the heart.