To describe the characteristics of enthesitis and arthritis in the active inflammatory stage of juvenile onset spondyloarthropathies (SpA) during a short-term follow-up.
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.
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.
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.