RADIOLOGIC FEATURES OF SYSTEMIC-ONSET JUVENILE RHEUMATOID-ARTHRITIS

Objective. To document the radiologic abnormalities in patients with s ystemic onset juvenile rheumatoid arthritis (SOJRA) including abnormal ities occurring early in the course of disease. Methods. A retrospecti ve review of the charts and radiographs of 42 consecutive children wit h SOJRA was carried out. Radiographs were reviewed by a single experie nced radiologist with no knowledge of the clinical course of the patie nts. Results. Soft tissue swelling and osteoporosis were the most comm on radiologic abnormalities (34/42; 81%). Cartilage loss and/or bone e rosions were also common, occurring in 50% of patients. Erosions occur red within 2 years of disease onset in 11/36 (31%). Subchondral irregu larity and sclerosis within 2 years of disease onset preceded erosions in 11 patients with serial radiographs. Severe radiologic abnormaliti es included joint ankylosis (8/42; 19%), subluxation (9/42; 21%), and protrusio acetabuli (4/42; 10%). Joint ankylosis occurred most commonl y between 3 and 5 years after disease onset and subluxation between 2 and 6 years. Conclusion. A subgroup of children with SOJRA develops ea rly destructive radiologic changes whose severity is comparable to tho se of children with rheumatoid factor positive polyarticular JRA. Earl y subchondral changes may be predictive of subsequent erosive disease in SOJRA and require prospective study using newer imaging techniques.