Objective: To describe the characteristics of enthesitis and arthritis in the active inflammatory stage of juvenile onset spondyloarthropathies (SpA) during a short-term follow-up.
Patients and methods: The study group included data of 33 patients with juvenile-onset SpA with enthesitis in > or = 3 sites, arthritis in > or = 4 joints, and erythrocyte sedimentation rate (ESR) of > or = 25 mm/h despite treatment, who participated in a 26-week, double-blind, sulfasalazine versus placebo trial that showed no significant differences between groups in regard to enthesitis and arthritis.
Results: Twenty-seven boys and 6 girls (mean age: 15.3 +/- 3.5 years; mean disease duration: 4.1 +/- 2.7 years) with the seronegative enthesopathy and arthropathy (SEA) syndrome (n = 20) or ankylosing spondylitis (AS; n = 13) comprised the group. Throughout the study, the mean (+/- SD) number of swollen joints and tender entheses were 4.6 +/- 2.5 and 8.3 +/- 5.4. The entheses and joints most frequently involved were the calcaneal attachments of the plantar fascia (87.9%) and Achilles tendon (81.8%) and the ankle (87.9%) and knee (72.7%), respectively. There was pain in the cervical, thoracic, and lumbar spine in 39.4%, 69.7%, and 63.6% of patients and in the sacroiliac joints in 48.5%. Mid-foot involvement (or tarsitis) occurred in 29 patients (87.9%). Except for the feet, the simultaneous occurrence of enthesitis and arthritis in other sites was rare. Overall, there were no significant differences between SEA syndrome and AS patients.
Conclusions: Disease activity shows a significant trend for entheses and joints of the feet and a significant prevalence of axial enthesitis in juvenile onset SpA. Mid-foot involvement appears to be the most characteristic and potentially, the most severe form of disease in these patients.