Role of musculoskeletal ultrasonography in the assessment of disease activity in juvenile idiopathic arthritis children

Aim of the work

To assess synovitis and disease activity by musculoskeletal ultrasound (MSUS) and clinical examination in children with juvenile idiopathic arthritis (JIA).

Patients and methods

Forty-one JIA patients underwent clinical examination of the joints, juvenile arthritis disease activity score (JADAS-27) assessment, and laboratory investigations. Twenty-four joints for each patient were evaluated by MSUS, including knees, wrists, 10 proximal interphalangeal, and 10 metacarpophalangeal. The parameters evaluated were synovial effusion, hypertrophy, effusion plus hypertrophy, tenosynovitis, and subclinical synovitis based on the Outcome Measures in Rheumatology definitions.

Results

The mean age of children was 11.7 ± 3.2 years, the disease duration was 4.2 ± 2.6 years and they were polyarticular (n = 22), oligoarticular (n = 12), systemic onset (n = 6) and one had ERA. They were 29 females and 12 males. The mean JADAS27 was 7.7 ± 6.9. The total number of joints assessed clinically and by MSUS was 984. 107 (10.9 %) joints showed clinical findings, while 135 (13.7 %) showed ultrasonographic features of synovitis. On clinical examination, 17 (15.9 %) joints had limited range of motion, and 90 (84 %) joints were tender including 38 (35.5 %) swollen. On MSUS examination, 28 (20.7 %) joints showed synovial effusion, 79 (58.5 %) hypertrophy, and 28 (20.7 %) had both synovial effusion and hypertrophy. Power Doppler signals were detected in 27 joints. MSUS detected subclinical synovitis in 60 (6.1 %) joints. Synovial effusion plus hypertrophy showed moderate concordance with joint swelling (k = 0.42).

Conclusion

The MSUS examination has a significant role in the detection of synovitis and the evaluation of disease activity in JIA patients. It is more sensitive than clinical examination.