Background/Purpose: Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood, leading to physical disability and poor quality of life. Advances in the treatment of JIA have led to higher remission rates. However despite clinical remission articular ultrasonography (US) can sometimes detect subclinical synovitis (SS). The aim of this study was to evaluate patients with JIA in remission and healthy controls for the presence of SS by US Power Doppler (PD), and evaluate its association with demographic and clinical variables.

Methods: Cross-sectional study of patients with JIA in remission and healthy controls, matched for age and gender. Inclusion criteria: oligoarticular and polyarticular JIA, clinical and laboratory remission (Wallace et al), between the ages 5 to 18 years. Clinical assessment: active/limited joint count, functional capacity by the Childhood Health Assessment Questionnaire (CHAQ), physician global visual analogue scale (VAS), patient global VAS, medications in use. US assessment evaluated 17 joints bilaterally. Ultrasonographic parameters included synovitis and synovial blood flow in PD. A moderate to severe degree of synovitis and/or any synovial flow present at the PD indicated the presence of SS. P-values were calculated based on the chi-square test, Fisher’s exact test, student’s T test and Mann-Whitney U test.

Results: Thirty-six patients (mean age 11.5 ± 3.7 years) and 36 controls (mean age 11.3 ± 3.7 years) were included and a total of 2448 joints were assessed. There were 36 JIA patients, 29 were girls, with a mean age at assessment of 11.5 ± 3.7 years and a mean age at disease onset of 4.3 ± 3.2 years. Sixteen patients had persistent oligoarticular JIA, 11 extended oligoarticular and 9 polyarticular with negative rheumatoid factor. Nine patients were off medication and 27 were on medication, with an average time of remission of 1.8 ± 2.2 years. SS was present in 46/2448 (1.8%). SS was more common in patients (41.6%) than in controls (13.9%) (p=0.009). The most frequently affected joints were the wrists (15), followed by elbows (9), ankles (8), toes (7), knees (4) and fingers (3). There were differences between patients and controls related to the presence of SS in elbows (p=0.033) and ankles (p=0.006). On ultrasonographic evaluation of JIA patients, 38/1224 (3.1%) had SS joints. Patients with JIA polyarticular/ extended oligoarticular subtypes and age at onset older than 6 years old had more SS (p=0.026 and  p=0.018, respectively). There were no differences in terms of gender, age at evaluation, presence of antinuclear antibodies, type of remission, duration of remission, type of medication, previous uveitis, previous intra-articular injections, physician VAS, patient VAS  and CHAQ. 

Conclusion: SS was present in 3.1% of joints from JIA patients considered to be in remission  especially in wrists, elbows, ankles, knees, fingers and toes. Although SS was shown to be more frequent in all JIA joints than in controls, we only observed significant difference in elbows and ankles joints. SS was more common in patients with polyarticular involvement (polyarticular and extended oligoarticular) and later age of JIA onset (greater than 6 years old).

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/assessment-of-subclinical-synovitis-by-power-doppler-ultrasonography-in-patients-with-juvenile-idiopathic-arthritis/