Juvenile idiopathic arthritis with dry synovitis: clinical and imaging aspects in a cohort of 6 patients

Abstract

Purpose - Objective. Dry synovitis is considered to be a rare form of juvenile idiopathic arthritis, incompletely understood and following a potentially destructive course, little described in the literature. We describe the clinical and radiological manifestations of dry synovitis. Material and methods. A retrospective study of 6 patients, in 2 pediatric rheumatology centers, with progressive articular limitations, without palpable synovitis and with radiologic articular damages. Neuromuscular conditions were excluded. Clinical and imaging (X-rays and MRI of wrist and/or pelvis) data were reviewed. Results. Six children (2 boys and 4 girls) aged from 3 to 15 years (median 9.7 years) presenting delayed motor development and/or progressive articular stiffness were included. Clinical examination showed a symmetric and polyarticular involvement without obvious clinical signs of synovitis. All patients had osteopenia, advanced bone age, irregular bone contours and/or erosions. Synovial thickening was present in 5/6 patients and bone erosions in 4/6 patients. Bone edema was variably present. Despite treatment, articular limitations persisted and imaging showed progressive articular damage. Discussion and conclusions. Dry synovitis can be considered as a descriptive term referring to the development of prospective symmetric polyarticular limitations. MRI reveals subclinical inflammation and destructive changes earlier than X-ray. The exact nature of this entity and a possible contribution of a metabolic or intrinsic bone disorder into its pathogenesis remain to be determined.