Juvenile idiopathic arthritis

Lore & Background

Juvenile idiopathic arthritis is an autoimmune disorder in which the body's own immune system attacks and destroys cells and tissues, particularly in the joints, for no apparent reason. The cause remains unknown, but it is thought to arise in genetically susceptible individuals due to environmental factors. The disease appears more common in girls and is most common in Caucasians.

Reader's Guide

Juvenile idiopathic arthritis is significant as the most common chronic rheumatic disease in childhood, affecting children under 16 years of age. Its prognosis has improved dramatically over recent decades, particularly with the introduction of biological therapies and a shift toward more aggressive treatment strategies. The condition has six biologically and clinically distinct forms: oligoarticular JIA, rheumatoid factor negative polyarticular JIA, rheumatoid factor positive polyarticular JIA, enthesitis-related arthritis, psoriatic JIA, and systemic JIA. A definitive diagnostic test is lacking; diagnosis is made clinically through a combination of laboratory and clinical factors, with cancer and other autoimmune or inflammatory conditions usually considered. Complications include joint damage, reduced growth, limb-length discrepancy, uveitis (which can lead to blindness if untreated), and macrophage activation syndrome in the systemic subtype. Treatment aims for normal physical and psychosocial functioning, an achievable goal for some children.

Did You Know?

• About one in six children with JIA develops inflammation in the front of the eye (anterior uveitis).
• Macrophage activation syndrome is a severe, potentially life-threatening complication that can occur in the systemic subtype of JIA.