JUVENILE RHEUMATOID ARTHRITIS

Juvenile Rheumatoid Arthritis

Juvenile Rheumatoid Arthritis

Juvenile rheumatoid arthritis (JRA) is the most common form of arthritis occurring in children. Juvenile rheumatoid arthritis does not represent a single disease but a constellation of disease processes which differ in their respective symptoms, treatments, and outcomes. Typically, JRA is clinically diagnosed if a child under the age of 16 has inflammation, limited motion, and swelling in at least one joint that lasts more than six weeks, provided that other diseases have been ruled out. However, in most cases, JRA is not a lifelong condition and symptoms may dissipate in weeks or months (Weiss, 2006).

JRA is not an early-onset form of adult rheumatoid arthritis but a distinctly separate disease. The key difference is that JRA causes chronic inflammation of the synovial membranes lining the joints, but this inflammation is not caused by an autoimmune attack as in adult rheumatoid arthritis. Patients with adult rheumatoid arthritis typically have elevated blood levels of an autoantibody called rheumatoid factor; this is unusual in JRA patients. There are three categories of JRA: pauciarticular, polyarticular, and systemic (Skinner, 2003). The systemic form occurs nearly equally in both sexes, but the first two forms are much more prevalent in females. There is an overall bimodal age distribution, with diagnosis being commonly made between 1 to 3 years or between 8 to 12 years.

Pauciarticular JRA affects approximately 50 percent of all JRA patients. It is defined as arthritis in one to four joints, most commonly involving the knee. A frequent and potentially serious complication of this form of JRA is iridocyclitis, an inflammation of the iris and ciliary body of the eye; all pauciarticular patients should receive regular ophthalmologist exams. Some patients, mostly females, have elevated blood levels of antinuclear antibodies and are at increased risk for iridocyclitis (Rubin, 2005). Another subgroup, mostly males, have the HLA-B27 gene; these patients are at increased risk for developing ankylosing spondylitis, a severe form of arthritis that mainly affects the spine and sacroiliac joints. After several months of symptoms, pauciarticular arthritis patients often enter remission periods lasting years, and thus, this form of JRA carries a relatively good prognosis.

Polyarticular JRA presents with a low-grade fever and at least five arthritic joints. Up to 30 percent of JRA patients have this form of the disease. Typically, the arthritis is symmetrical and affects the same joints on both sides of the body. About 25 percent of these patients actually have elevated levels of rheumatoid factor in their blood, which is typically unusual in JRA. Polyarticular patients, especially those who are positive for rheumatoid factor, often have chronic disease courses (Petty, 2003).

Systemic JRA, or Still's disease, accounts for about 20 percent of JRA patients. The systemic form is characterized by high fever, rash, arthritic joints, swollen lymph nodes, enlarged liver and spleen, pericarditis, and pleuritis. Also, these patients have markedly elevated white blood cell counts. One in four patients with systemic JRA progresses to long-term severe ...