Juvenile Rheumatoid Arthritis (JRA)
Are There Different Types of Juvenile Rheumatoid Arthritis? continued...
Pauciarticular (paw-see-are-tick-you-lar) means that four or fewer joints are involved. This is the most common form of JRA; about half of all children with JRA have this type.
This type of JRA typically affects large joints, such as the knees. Girls under age 8 are most likely to develop this type of JRA. Some children with pauciarticular JRA have special proteins in the blood called antinuclear antibodies (ANAs).
Eye disease affects from 20% to 30% of children with pauciarticular JRA and is more common in children with ANAs. Regular exams by an ophthalmologist (a doctor specializing in eye diseases) are necessary with JRA.
The ophthalmologist treats serious eye problems such as iritis (inflammation of the iris, the colored part of the eye) or uveitis (inflammation of the inner eye). Many children with pauciarticular disease outgrow JRA by adulthood. Still, eye problems can continue and joint symptoms may recur in some people.
About 30% of all children with JRA have polyarticular disease, in which five or more joints are affected. The small joints, such as those in the hands and feet, are most commonly involved. However, the disease may also affect large joints.
Polyarticular JRA often is symmetrical. This means it affects the same joints on both sides of the body. Some children with polyarticular disease have rheumatoid factor in their blood. These children often have a more severe form of the disease. Doctors consider this to be the same as adult rheumatoid arthritis.
Along with joint swelling, the systemic form of JRA is characterized by fever and a light pink rash. This type of JRA may affect internal organs such as the heart, liver, spleen, and lymph nodes.
The systemic form (called Still's disease) affects 20% of children with JRA. Almost all children with this type of JRA test negative for both rheumatoid factor and ANA.
A small percentage of these children with systemic JRA develop arthritis in many joints. They may have severe arthritis that continues into adulthood.
How Is Juvenile Rheumatoid Arthritis Diagnosed?
JRA is often difficult to diagnose. Sometimes children with JRA do not complain of pain. In fact, parents may not be aware of symptoms such as swelling.
Some symptoms of JRA are similar to other serious conditions such as infection, cancer, bone disorders, Lyme disease, and lupus.
Doctors usually go through a series of exams and tests to see if the patient has JRA. During the exam, the doctor will review the family medical history to see if there's a possible genetic link. The doctor will also review the patient's medical history to see how long the child has had symptoms.
In addition, the doctor will do a physical exam to look for joint swelling, rashes, signs of internal organ inflammation, and/ or eye problems. A series of blood tests and joint and tissue fluid tests are also done to check for infection and to confirm the diagnosis.
Lastly, the physician may use X-rays to check for joint damage and signs of inflammation. Also, lab tests are done including ANA, rheumatoid factor, HLA-B27 typing, hemoglobin and blood count testing and urinalysis, and erythrocyte sedimentation rate.