Objective: To study clinical characteristics of children with enthesitis related arthritis (ERA).
Methods: Twelve patients fulfilling the international league of associations for rheumatology (ILAR) criteria for classification of juvenile idiopathic arthritis (JIA) and ERA were referred to our department between August and November, 2002. Their gender, age, family history, clinical manifestations, imaging data, laboratory data and treatment regimens were analyzed retrospectively.
Results: Of the 12 patients, 11 were male, only one was female; their age ranged from 4 to 16 years, and the median age was 10.5 years. Ten (83%) of the patients were older than eight years. Among their first degree relatives, one had definite ankylosing spondylitis (AS), and 3 presented with a history of inflammatory low back pain. Enthesitis occurred in 9. Synovitis occurred in 11, most of which were oligoarthritis, predominantly affecting large joints of the lower limbs in an asymmetric pattern. Seven patients underwent CT scan, and only one had erosions of the sacroiliac joints to achieve a diagnosis of juvenile AS. Ten had fever at the onset, and one had a history of diarrhea preceding the symptoms of arthritis. Urethritis and balanitis circinata occurred in 3 cases fulfilling the classification criteria of Reiter's syndrome, with conjunctivitis in 2 and corneitis in one. Elevated inflammatory indicators such as white blood cell, neutrophil, platelet, erythrocyte sedimentation rate, C-reactive protein, immunoglobulins and serum complement C3 were common during the acute illness. Mild anemia was found in 4, and reactive hemophagocytosis in 4 bone marrow specimens. DNA of human parvovirus B19 was detected in sera of 2 cases. One had positive IgM antibody to coxsackie virus B. All 12 cases were rheumatoid factor negative and HLA-B27 positive. Nonsteroidal anti-inflammatory drugs and sulfasalazine were the mainstay of treatment. Corticosteroids were added in 3 cases as a "bridge" therapy due to the severe systemic inflammation. Methotrexate was used in 4 cases with refractory disease or with the hip involved, and in 2 of them cyclophosphamide was added.
Conclusion: The clinical characteristics of ERA can facilitate an early diagnosis so as to avoid joint damage and disabilities.