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Polyarticular JRA

(see also: 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;

References