Juvenile rheumatoid arthritis (JRA) is best defined as the condition of chronic
synovitis in children. Such chronic
childhood arthritis probably includes several distinct disease processes. Recognizable subgroups are systemic-onset disease (20%),
rheumatoid factor-negative polyarthritis (25%),
rheumatoid factor-positive
polyarthritis (5%), pauciarthritis associated with
antinuclear antibodies and chronic
iridocyclitis (30%-35%), and pauciarthritis associated with
sacroiliitis and
HLA-B27 (10%-15%).
Rheumatoid factor-positive
polyarthritis appears to be the childhood equivalent of classic adult
rheumatoid arthritis; the pauciarthritis associated with HLA B27 appears to be closely related to the spondyloarthropic diseases. Although there are no diagnostic laboratory tests, various subgroups differ in immunogenetic findings as well as in clinical appearance and prognosis. A wide variety of conditions (
infectious diseases, childhood
malignancies, genetic and congenital conditions, and noninflammatory musculoskeletal lesions) can mimic JRA and must be considered in the differential diagnosis. The outlook for most children with JRA is good; fewer than 20% have progressive destructive disease (generally those with
rheumatoid factor-positive or systemic-onset disease).
Therapy rests on the conservative use of
antirheumatic drugs, active
physical therapy programs, maintenance of activities, and attention to the psychosocial development of the whole child.
Orthopedic surgery can be helpful, particularly in the rehabilitation of children who have suffered severe joint destruction or
deformity. Combined orthodontic and
oral surgery therapy can restore function and appearance for young people with the
micrognathia of temporomandibular joint involvement.