Musculoskeletal ultrasound in Paediatric Rheumatology: a retrospective analysis

Objectives: Musculoskeletal Ultrasound (MSK-US) has become increasingly important in the diagnosis and follow-up of children with rheumatic diseases. We describe the experience of a large Portuguese centre and study the added value of MSK-US in the clinical assessment of paediatric rheumatic diseases. Material and methods: Patients were observed by assistant Rheumatologists, a clinical diagnosis was assigned and MSK-US requested. 330 MSK-US exams were performed to 222 children with rheumatic inflammatory diseases. The children's ages were between 1 and 18 years (mean=11.7 +/- 4.7 years) and 67.6% were female. Synovial membrane proliferation, intra-articular effusion, cartilage abnormalities, erosions and periarticular affections were searched in each joint. Clinical and ultrasonography data were compared. Results: MSK-US detected synovitis in 100 of 194 exams (51.5%) of patients with that clinical information and in 36 of 136 exams (26.5%) of patients who presented other clinical findings. In those in which MSK-US did not confirm the clinical information of synovitis (94; 48.5%), we detected tenosynovitis/tendinopathy in 13 cases (13.8%) and synovial cyst in four (4.3%). The remaining patients had no ultrasonography changes and MSK-US helped to exclude synovitis. The sensitivity for arthritis clinical assessment was good (73.5%), with modest specificity (51.5%), an accuracy of 60.6% and precision of 51.5%. Ultrasonography synovitis was mostly found in the knee (37.5%), followed by the ankle (22.8%) and hip (10.3%). Overall, 39 exams showed ultrasonographic tenosynovitis/tendinopathy, 15 of which had the same clinical diagnosis. Tenosynovitis/tendinopathy was mostly found in the ankle (59.0%) and knee (23.1%) areas. Conclusions: MSK-US is an important aid to clinical evaluation, allowing both the detection and exclusion of joint pathology in children, contributing to a better assessment.