Juvenile chronic arthritis: classification, differential diagnosis and prognosis.

Although the nomenclature and classification of juvenile chronic polyarthritis is not uniform, the division into systemic, polyarticular and pauciarticular forms is generally accepted. The characteristic symptoms, the division into subgroups according to age, clinical course and serology as well as the differential diagnostic considerations pertaining to each form are described. Most of the children with the pauciarticular form have a good prognosis; however, in 15% of these cases the disease changes into polyarticular JCA. The systemic form has the least favorable prognosis, while the prognosis of polyarthritic JCA depends upon the presence of the IgM-Rheuma factor. In seronegative patients the prognosis also depends on the age at onset of the disease and on the quality of the treatment of the joints during the acute phases.