Enthesitis is an important clinical manifestation and is a diagnostic criterion for juvenile idiopathic enthesitis-related arthritis (JIA-ERA). Ultrasound (US) is a highly sensitive method of detection of enthesitis in adult spondyloarthropathies. However, since the data on JIA and the preformance of US compared to clinical examination is limited, we aimed to compare the accuracy of US and clinical examination in JIA-ERA.
Patients with JIA-ERA (ILAR criteria) were enrolled in the study after consent. Besides data on disease variables, enthesitis was evaluated clinically as well as by ultrasound. Six entheseal sites (iliac crest, superior pole patella, inferior pole patella, tibial tuberosity, tendoachilles and plantar fascia) on both sides of the body were examined in each patient. Features of acute and chronic enthesitis were noted.
360 entheseal sites in 30 male patients (26 positive for HLA-B27), with a median age of 16 years and median disease duration of 4 years were evaluated. Median Madrid Sonology Enthesitis Index (MSEI) was 2.0 (MSEI-Acute) (IQR 0-3) and 1.0 (MSEI-Chronic) (IQR 0-1). Ultrasound enthesitis was seen in 25 of 30 patients whereas clinical enthesitis was present in 15 patients only. USG picked up 20 (47 vs. 27) more sites of enthesitis as compared to clinical examination. The concordance rate was 89.4%. Discordance was more at tibial tuberosity, superior pole patella and tendoachilles entheses.
Ultrasonography detects subclinical enthesitis in a proportion of patients with JIA-ERA. It can be a useful, cost-effective and safe diagnostic tool in the workup of JIA patients.