Ultrasound-detected synovial abnormalities are frequent in clinically inactive juvenile idiopathic arthritis, but do not predict a flare of synovitis.

OBJECTIVES: To investigate whether children with juvenile idiopathic arthritis (JIA) in clinical remission have subclinical synovial disease on ultrasound, and whether ultrasound abnormalities predict an early flare of synovitis.
METHODS: Thirty-nine consecutive children who had clinically defined inactive disease (ID) for a minimum of 3 months underwent ultrasound assessment of 52 joints. All joints were scanned for synovial hyperplasia, joint effusion, power Doppler (PD) signal and tenosynovitis. Patients were then followed clinically for up to 2 years until a flare of synovitis occurred in one or more joints, or until the 2-year visit if the disease remained in clinical remission.
RESULTS: Synovial hyperplasia, joint effusion, PD signal and tenosynovitis in at least one joint were detected in 76.9%, 66.7%, 33.3% and 15.4% of patients, respectively. During the 2-year follow-up, 24 patients (61.5%) experienced sustained ID, whereas 15 patients (38.5%) had a flare of synovitis in a total of 45 joints after a median of 10.6 months (range 6.3-13.7 months). At study entry, the rate of synovial hyperplasia, joint effusion and tenosynovitis was comparable between patients with persistent ID and patients with synovitis flare, whereas patients with persistent ID had a greater frequency of PD signal than patients with synovitis flare. Only 17 of the 45 flared joints had ultrasound abnormalities at study entry.
CONCLUSION: The authors found that ultrasound-detected synovial abnormalities are common in children with JIA in clinical remission. However, the presence of ultrasound pathology did not predict an early flare of synovitis in the affected joints.