Juvenile Rheumatoid Arthritis

Juvenile rheumatoid arthritis is persistent or recurring inflammation of the joints similar to rheumatoid arthritis (see Section 5, Chapter 67) but beginning before age 16.

Juvenile rheumatoid arthritis is an uncommon disease characterized by inflammation of joints or connective tissue. The cause is unknown. Although juvenile rheumatoid arthritis is not considered a hereditary disorder, hereditary factors may increase a child's chance of developing it.

Symptoms and Complications

There are several types of juvenile rheumatoid arthritis, each with different characteristics. The type of juvenile rheumatoid arthritis is determined by which symptoms develop during the first months of the disease and how many joints are affected.

In pauciarticular juvenile rheumatoid arthritis, four or fewer joints, usually those of the leg, are affected. The knee is usually the first joint affected. The hip and shoulder are usually spared. Occasionally, a single toe, a finger, a wrist, or the jaw becomes stiff and swollen. The back may also be involved. The joint pain and swelling may persist or come and go.

In polyarthritis, five or more (sometimes as many as 20 to 40) joints are affected. The inflammation usually affects the same joint on both sides of the body--for example, both knees or both hips. The jaw, neck joints, and wrists may be affected. Symptoms may develop slowly; fever and enlargement of the spleen or lymph glands can occur. Inflammation may develop in the tendons and connective tissues around joints (tenosynovitis), causing pain, swelling, and warmth.

In systemic disease (Still's disease), any number of joints can be involved. Inflammation also occurs at sites other than the joints. The liver, spleen, and lymph nodes may enlarge, and sometimes inflammation develops in the membrane surrounding the heart (pericarditis). Rarely, the kidneys become inflamed. A high fever and rash may appear before joint pain and swelling. The fever comes and goes, usually for at least 2 weeks. Temperature is usually highest in the afternoon or evening (often 103° F or higher), then returns rapidly to normal. A child with fever may feel tired and less energetic. A rash made up of flat, pink or salmon-colored patches--mainly on the trunk and the upper part of the legs or arms--appears for hours (often in the evening). The rash can reappear days later on a different part of the body.

With any type of juvenile rheumatoid arthritis, the joints may be stiff when the child awakens. Joints often become swollen and warm. Later, joints may become painful, but the pain may be milder than expected from the amount of swelling. Pain may become worse when the joint is moved. A child may be reluctant to walk. Joint pain tends to persist for weeks or months.

Any type of juvenile rheumatoid arthritis can interfere with physical growth. Joint deformities often develop. When juvenile rheumatoid arthritis interferes with growth of the jaw, a small chin (micrognathia) can result. Long-standing (chronic) joint inflammation can eventually cause deformities or permanent damage of the affected joint.

Inflammation of the iris in the eye (iridocyclitis) can develop with any kind of juvenile rheumatoid arthritis, but most often iridocyclitis develops with pauciarticular juvenile rheumatoid arthritis or polyarthritis. Iridocyclitis may cause eye redness, eye pain, or loss of vision, but it can develop without any symptoms. If untreated, iridocyclitis can lead to permanent eye damage.

Diagnosis

A doctor diagnoses juvenile rheumatoid arthritis based on the child's symptoms and the results of a physical examination. There is no single, definitive laboratory test for juvenile rheumatoid arthritis. Blood is tested for rheumatoid factor and antinuclear antibodies, which are present in some people with rheumatoid arthritis and related diseases (for example, autoimmune diseases, such as lupus, polymyositis, or scleroderma). However, many children with juvenile rheumatoid arthritis do not have rheumatoid factor or antinuclear antibodies in their blood. Also, children with many other conditions can have rheumatoid factor or antinuclear antibodies in their blood. X-rays eventually may show characteristic changes in the bones or joints. The child must be examined regularly by an ophthalmologist for iridocyclitis regardless of whether symptoms are present.

Treatment and Prognosis

The types of juvenile rheumatoid arthritis are treated similarly, and the drugs used to reduce pain and inflammation are the same as for rheumatoid arthritis (see Section 5, Chapter 67). However, children with juvenile rheumatoid arthritis often also need treatment for iridocyclitis. Iridocyclitis is treated with corticosteroid eye drops or ointments, which suppress inflammation. Eye drops that widen (dilate) the pupil can decrease eye pain from iridocyclitis. Both types of drugs can prevent glaucoma and blindness. For unusually severe iridocyclitis, eye surgery may be needed.

As in rheumatoid arthritis in adults, non-drug therapies are also used in children; for example, splinting and flexibility exercises, to prevent permanent stiffening of joints.

Symptoms of juvenile rheumatoid arthritis completely disappear in a high proportion of affected children. Up to half of the children with pauciarticular juvenile rheumatoid arthritis and about one quarter or more of children with polyarthritis or systemic disease have a complete remission.