Rheumatoid arthritis (RA) is a chronic inflammatory disease that damages and eventually destroys joints. What many people don't realize is that this disease may affect children... not just adults!

Though inflammation is a normal response of the body's immune system, in arthritis, the inflammation is excessive and targets normal tissue leading to damage and destruction. The inflammation in the joints causes pain, stiffness, and swelling as well as many other symptoms. The inflammation often affects other organs and systems of the body as well. Juvenile rheumatoid arthritis (JRA) is not one disease, but a group of diseases. What they all have in common is chronic joint inflammation. Besides this common feature, these diseases are very different in their symptoms, their treatments, and their outcomes.

" Pauciarticular disease affects only a few joints, fewer than 5. The large joints, such as the shoulder, elbow, hip, and knee, are most likely to be affected. This type of JRA is most common in children younger than 8 years of age. Children who develop this disease have a 20-30% chance of developing inflammatory eye problems and need frequent eye examinations. Children who develop this disease when older than 8 years have a higher-than-normal risk of developing an adult form of arthritis. About 50% of all children with JRA have this type.

" Polyarticular disease affects 5 joints or more, sometimes many more. The small joints such as those in the hands and feet are most likely to be affected. This type can begin at any age. In some cases, the disease is identical to adult-type RA. This type accounts for about 30% of cases of JRA.

" Systemic disease affects many systems of the body. Children may have high fevers, skin rashes, and problems caused by inflammation of the internal organs such as the heart, spleen, liver, and other parts of the digestive tract. It usually, but not always, begins in early childhood. Physicians sometime call this Still's disease. This type accounts for about 20% of cases of JRA.

Children with JRA may experience complications specific to their type of JRA.

The most common complications in children with JRA relate to adverse effects of medications taken to treat the disease, particularly non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin). When taken chronically, these drugs can cause irritation, pain, and bleeding in the stomach and upper intestine. They also can cause problems in the liver and kidneys that often produce no symptoms until they are very severe. In some cases, the child must undergo frequent blood tests to screen for these problems.

Eye inflammation- iritis- occurs in about 30 per cent of children. It must be treated aggressively in order to prevent blindness.

Some children with JRA have emotional or psychological problems. Bouts of depression and problems functioning in school are the most common.

The mortality (death) rate in children with JRA is somewhat higher than in healthy children. The highest death rate in children with JRA occurs among patients with systemic JRA who develop systemic symptoms (eg, pleural and pericardial disease- disease affecting the lining of the lungs and heart). JRA can also evolve into other diseases, such as systemic lupus erythematosus (SLE) or scleroderma, which have higher death rates than pauciarticular or polyarticular JRA.

Treatment for JRA, like that for adult-type rheumatoid arthritis, has improved dramatically in the last 30 years, thanks mainly to the development of new medications.

These include the use of sulfasalazine, methotrexate, and biologic medications such as etanercept (Enbrel).