(see also: juvenile RA menu)
- definition: > 5 involved joints;
- large and small joint may be affected;
- accounts for about 50% of patients w/ JRA;
- may occur at 1-3 yrs or during early adolescence (after age 10);
- children w/ seronegative arthritis usually present before age 5 years and have iridocyclitis if fewer than five joints are involved;
- destruction of joints is less severe than that of seropositive pts, who present after age 10 and have adult-like disease progression;
- differential dx
- generally good: 60% of pts in remission after 15 yrs, however, large subset will develop cripling arthritis;
- severe hip disease is a major late disability.
- leg length inequality may occur (either larger or smaller)
- usually occurs w/ knee involvment;
- ANA: positive in 30%;
- RF is usually negative in child, but may be pos. in adolescent;
- w/ positive RF, more likely to have rheumatoid nodules, joint erosions, & Felty's syndrome (RA, splenomegaly, & leukopenia);
- osteopenia and early ossification of carpal bones visible on radiographs;
- distal ulnar physis matures early, & short ulna leads to ulnar translocation;
- frequently, there is symmetric involvement of knees, wrists, & ankles;
- may also have involvment of cervical spine (60 %), hips, shoulder & TMJ.
- cervial spine Involvement: common at C2-3;
- constitutional symptoms:
- growth retardation, low grade fever, mild organomegaly, adenopathy, and anemia;
- chronic iridocyclitis is less common than in pauciarticular JRA;
- Upper Extremity- Hands and Wrist:
- PIP and MP joints are involved in approx. 20% of pts;
- swan neck deformity: responds to use of a splint;
- boutonniere deformity:
- forces of usage are contributory, accounting for fact that children, w/ no work demands, have less ulnar drift than do adults;
- in the study by Lovell DJ, et al (2000), the authors evaluated the safety and efficacy of etanercept, a soluble tumor necrosis factor receptor (p75):Fc fusion protein, in children with polyarticular juvenile rheumatoid arthritis who did not tolerate or had an inadequate response to methotrexate;
- patients 4-17 years received 0.4 mg of etanercept per kg of body wt subQ twice weekly for up to 3 months in the initial, open-label part of a multicenter trial;
- at the end of the open-label study, 51 of the 69 patients (74 %) had had responses to etanercept treatment;
- in the double-blind study, 21 of the 26 patients who received placebo (81 percent) withdrew because of disease flare, as compared with 7 of the 25 patients who received etanercept (28 percent) (P=0.003).
- Etanercept in children with polyarticular juvenile rheumatoid arthritis. Pediatric Rheumatology Collaborative Study Group.