Polyarticular JRA

- See: juvenile RA menu

- Discussion:
    - 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
    - prognosis:
           - 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;

- Labs:
    - 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);

- Radiographs:
    - osteopenia and early ossification of carpal bones visible on radiographs;
    - distal ulnar physis matures early, & short ulna leads to ulnar translocation;

- Clinical Presentation:
    - 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:
         - hands:
                - PIP and MP joints are involved in approx. 20% of pts;
                - swan neck deformity: responds to use of a splint;
                - boutonniere deformity:
         - wrist:
                - forces of usage are contributory, accounting for fact that children, w/ no work demands, have less ulnar drift than do adults;

- Treatment:
    - 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. 

Radiographic changes in juvenile chronic polyarthritis.   

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, August 21, 2012 4:31 pm