Although scientists don't know the exact causes of JRA yet, much research is being done on JRA and other forms of arthritis. They do know that JRA involves abnormalities of the immune system, which defends our bodies against germs, such as bacteria and viruses. When the immune system isn't working properly - as in a condition like JRA, for example - it has difficulty telling the difference between germs and the body's own tissues. This confusion causes the immune system to mount an attack and release chemicals that actually damage the body's own healthy tissues. This results in the type of inflammation that causes the symptoms of JRA.

It is also known that JRA is not contagious. You can't catch it from someone else or pass it along to another person the way you might a cold or other infection.

What Do Doctors Do?

JRA can be difficult to diagnose. All of the forms of this type of arthritis involve inflammation, but they also involve a variety of symptoms and require different kinds of treatment. No single test can diagnose all the forms of JRA and other types of arthritis. The doctor will take a thorough medical history and do a complete physical examination to detect joint swelling, eye problems, and rashes. He or she may do blood tests, X-rays, and, in some cases, may use a needle to take a sample of synovial (joint) fluid for examination. The doctor may need to follow the course and symptoms of a person with JRA for several months to determine the particular form of the condition the person has.

Certain infections, such as parvovirus infection and Lyme disease, have similar symptoms and may be mistaken for JRA. These possibilities must be ruled out before a diagnosis of JRA can be confirmed.

Reviewed by: John Bohnsack, MD
Date reviewed: May 2003
Originally reviewed by: Gail McIlvain-Simpson, MSN, RN