Juvenile idiopathic arthritis

Abstract

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatologic disease in childhood, which represents a nonhomogeneous group of disorders that share the clinical manifestation of arthritis lasting at least 6 wk under the age of 16. The exact diagnosis requires exclusion of other diseases that cause arthritis. The exact etiopathogenesis of JIA is still unknown. The interactions between genetic factors, environmental exposures and immune mechanisms are thought to contribute to pathogenesis of the disease. The “International League Against Rheumatism” classification divides JIA into 7 subtypes: oligoarticular JIA, rheumatoid factor (RF) positive polyarticular JIA, RF negative polyarticular JIA, systemic-onset JIA, enthesitis-related arthritis, juvenile psoriatic arthritis and undifferentiated JIA. Each subgroup of JIA is characterized by a different mode of presentation, disease course and outcome. The improvements in treatment of JIA in the last 2 decades, such as the early introduction of intraarticular corticosteroids, methotrexate and biologic agents, have dramatically upgraded the prognosis of the disease. If untreated, JIA may cause devastating results, such as disability from joint destruction, growth retardation, blindness from chronic iridocyclitis, and even multiple organ failure and death in systemic-onset JIA. The aim of treatment is the induction of remission and control the disease activity to minimize the pain and loss of function, and to maximize quality of life. JIA is a disease having a chronic course, which involves active and inactive cycles over the course of years. Recent studies showed that nearly half of the patients with JIA enter adulthood with their ongoing active disease. This review elucidates how recent advances have impacted diagnosis, pathogenesis and current treatment.

Keywords: Juvenile idiopathic arthritis, Classification, Etiopathogenesis, Treatment, Prognosis, Outcome

Core tip: Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatologic disease in children. Diagnosis of JIA is based on the history and physical examination findings. There is not a diagnostic laboratory test for JIA. Recent advances in the understanding of the immune system pathways involved in inflammation and self-tolerance have provided new targets for treatment of JIA. Biologic agents targeting key cytokines implicated in JIA, suh as tumor necrosis factor α, interleukin (IL)-1, and IL-6 as well as signaling molecules involved in the regulation of B-cell and T-cell lymphocyte responses, have promising results.