Juvenile Rheumatoid Arthritis
Juvenile rheumatoid arthritis (JRA) affects children under age 16 and consists of several conditions characterized by chronic synovitis and joint swelling, pain, and tenderness. The disease can also produce extraarticular signs and symptoms that involve the skin, heart, lungs, liver, spleen, and eyes. Major types of JRA include systemic (Still's disease or acute febrile type), polyarticular. and pauciarticular.
Depending on the type, JRA may occur as early as age 6 weeks but seldom before age 6 months; peak onset is between ages 1 and 3 and 8 and 12. JRA is the major chronic rheumatic disorder of childhood and occurs in an estimated 150,000 to 250,000 children in the United States, affecting twice as many girls as boys.
Researchers continue to probe for the causes of JRA. Various findings suggest links to genetic factors or to an abnormal immune response. Viral or bacterial (particularly streptococcal) infection, trauma, and emotional stress may be precipitating factors, but their exact relation to the disease remains unclear.
Signs and symptoms
Signs and symptoms of juvenile rheumatoid arthritis may include:
Like other forms of arthritis, JRA is characterized by times when symptoms are present (flares) and times when symptoms disappear (remissions).
Complete blood count usually shows decreased serum hemoglobin levels and increased neutrophil (neutrophilia) and platelet (thrombocytosis) levels. Other blood test findings include an elevated erythrocyte sedimentation rate and elevated C-reactive protein, serum haptoglobin, immunoglobulin, and C3 complement levels.
Antinuclear antibody test results may be positive in patients with polyarticular JRA and in those with pauciarticular JRA with chronic iridocyclitis.
Rheumatoid factor (RF) appears in about 15% of patients with JRA. In contrast, about 85% of patients with rheumatoid arthritis test positive for RF. Patients with polyarticular JRA may test positive for RF.
The presence of human leukocyte antigen (HLA)-B27 in blood tests may forecast later development of ankylosing spondylitis.
X-ray studies demonstrate early structural changes associated with JRA. These include soft-tissue swelling, effusion, and periostitis in affected joints. Later evidence includes osteoporosis and accelerated bone growth followed by subchondral erosions, joint space narrowing, bone destruction, and fusion.
Successful JRA management usually calls for anti-inflammatory drugs, physical therapy, carefully planned nutrition and exercise, and regular ophthalmologic examinations. Both the child and the parents must be involved in therapy.
Aspirin is the initial drug of choice. Dosage is based on the child's weight. Additional nonsteroidal antiinflammatory drugs (NSAIDs) may be used. If they prove ineffective, gold salts, hydroxychloroquine, and penicillamine can be tried. Because of adverse effects, corticosteroids are reserved for treating systemic disorders (such as pericarditis and iritis) that resist treatment with NSAIDs. Corticosteroids and mydriatic drugs are commonly prescribed for iridocyclitis. Investigational drug therapy includes low-dose cytotoxic agents. such as methotrexate.
Physical therapy promotes regular exercise to maintain joint mobility and muscle strength, thereby preventing contractures, deformity, and disability. Good posture, gait training, and joint protection are also beneficial. Splints help reduce pain, prevent contractures, and maintain correct joint alignment. Applying heat during passive exercises (for example, by whirlpool, paraffin, or hot packs) is beneficial.
Surgery is usually limited to soft-tissue releases to improve mobility. Joint replacement is delayed until the child matures physically and can tolerate vigorous rehabilitation.
There is no known prevention for JRA.
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