Juvenile rheumatoid arthritis (JRA), often referred to by doctors today as juvenile idiopathic arthritis (JIA); is a type of arthritis that causes joint inflammation and stiffness for more than six weeks in a child aged 16 or younger. It affects approximately 50,000 children in the United States. Inflammation causes redness, swelling, warmth, and soreness in the joints, although many children with JRA do not complain of joint pain. Any joint can be affected, and inflammation may limit the mobility of affected joints.
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JRA is an autoimmune disorder, which means that the body mistakenly identifies some of its own cells and tissues as foreign. The immune system, which normally helps to fight off harmful, foreign substances such as bacteria or viruses, begins to attack healthy cells and tissues. The result is inflammation — marked by redness, heat, pain, and swelling.
Researchers still don’t know exactly why the immune system goes awry in children who develop JRA, although they suspect that it’s a two-step process. First, something in a child’s genetic makeup gives them a tendency to develop JRA. Then an environmental factor, such as a virus, triggers the development of JRA.
Symptoms/Effects
JRA may cause fever and anemia, and can also affect the heart, lungs, eyes, and nervous system. Arthritic episodes can last for several weeks and may recur; although the symptoms tend to be less severe during later recurrent attacks. Treatment is similar to that for adults; with an additional heavy emphasis on physical therapy and exercise to keep growing bodies active. Many of the strong medicines used for adults, though, aren’t usually needed for JRA. Permanent damage from juvenile rheumatoid arthritis is now rare; and most affected children recover from the disease fully without experiencing any lasting disabilities.
Differences Between Juvenile and Adult Arthritis
The main difference between juvenile and adult arthritis is that some children with JRA outgrow the illness; while adults usually have lifelong symptoms. Studies estimate that by adulthood, JRA symptoms disappear in more than half of all affected children. Additionally, unlike adult rheumatoid arthritis, JRA may affect bone development as well as the child’s growth.
Another difference between JRA and adult rheumatoid arthritis is the percentage of people who are positive for rheumatoid factor in their blood. About 70% to 80% of all adults with rheumatoid arthritis have rheumatoid factor, but fewer than half of all children with rheumatoid arthritis are rheumatoid factor positive. The presence of rheumatoid factor indicates an increased chance that JRA will continue into adulthood.