Clinical analysis of 570 cases with juvenile rheumatoid arthritis: results of a nationwide retrospective survey in Japan.

The purpose of the present study was to investigate the incidence of juvenile rheumatoid arthritis (JRA) among Japanese children and to evaluate the clinical features of this disease. A questionnaire was sent to the department of pediatrics of 1290 hospitals in Japan, in 1994, asking for the number of rheumatic patients during the past 10 years. Subsequently, a second questionnaire was sent asking for the type of onset, clinical features, treatment, and other details. The results of 570 cases were obtained. Of these, 310 cases (54%) were the systemic onset type, 140 cases were the polyarticular onset type (25%), and 120 cases (21%) were the pauciarticular onset type. Hence, in the present series of children, the proportion of the pauciarticular type was less than the other two types of JRA. In the laboratory findings of the systemic onset type, hyperferritinemia and thrombocytosis were noted, in addition to leukocytosis, positive C- reactive protein (CRP) and accentuated erythrocyte sedimentation rate (ESR). The rheumatoid factor was positive in 50% of patients with the polyarticular onset type. Chronic uveitis was recognized in 13 cases (10.8%) of the pauciarticular onset type. In four girls, uveitis started before the onset of arthritis. Non-steroidal anti-inflammatory drugs were used in almost one-third of cases, and methotrexate (MTX) was used in 12.8% of cases. The quality of life of children with JRA was disturbed in almost 20% of cases. Therefore, for the early and definitive diagnosis of the systemic type of JRA, diagnostic procedures including thrombocyte counts and serum ferritin level, should be performed. In order to obtain good results and to avoid side effects, a protocol for the use of disease modifying anti-rheumatic drugs and immunosuppressants, especially for the use of MTX, must be established.