Systemic onset juvenile rheumatoid arthritis.

Systemic onset juvenile rheumatoid arthritis (SoJRA) accounts for 10-20% of all JRA, affecting males and females equally and occurring most frequently under the age of 5 years. It is characterized by arthritis, daily spiking fever, an evanescent rash, serositis and a variety of other extra-articular features. Exclusion of systemic infections, malignancies and connective tissue diseases is most important in establishing the diagnosis. The disease has a wide range of severity from a short monocyclic course to a prolonged chronic course with severe destructive arthritis in approximately one third of patients. Destructive arthritis, secondary amyloidosis and treatment complications including infections, osteoporosis, growth retardation and the macrophage activation syndrome account for the significant morbidity and mortality associated with the disease. Pharmacological management includes non-steroidal anti-inflammatory drugs, corticosteroids, methotrexate and an emerging role for cyclosporine A and cytotoxic drug therapy. Elucidation of the immunopathogenetic mechanisms may lead to new targeted therapy.