To determine the prevalence of abnormalities detected by ultrasonography (US) in children with juvenile idiopathic arthritis (JIA) showing clinically inactive disease (ID) on medication and off medication.
1) JIA patients, 2) clinician-determined ID, 3) JIA drugs withdrawal or stably dosed modified anti-rheumatic drugs (DMARDs) therapy for at least 6 months prior to inclusion, 4) biologics naïve patients. Clinical and US assessments were performed on 44 joints, which were scored for grey-scale (GS) synovitis and Power Doppler (PD) signal. PD signal inside intra-articular synovium or tendon sheath was considered as inflammatory activity.
Thirty-four patients were included, of whom 23 patients were labelled as ID on medication and 11 patients without medication. The duration of the current episode of ID at the inclusion time was 9.5 months. Although it was longer for the group off medication there was no significant difference between the two groups (p=0.06). Thirteen patients presented US findings. Number of US-detected synovial abnormalities was higher in patients on medication, but there were no significant differences between both groups in the detection of GS synovitis (p=0.86), GS tenosynovitis (p=0.78) and PD signal (p=0.38). Out of 37 joints presenting US-determined GS-synovitis, 18 joints showed PD signal.
Our study provides evidence of synovitis and tenosynovitis on B-mode US in JIA patients with clinical inactivity. In addition, inflammatory activity upheld by power-Doppler has been shown in a few joints from patients on medication.