Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA), formerly known as juvenile rheumatoid arthritis or juvenile chronic arthritis, is the most common chronic rheumatic disease of childhood. It encompasses a heterogeneous group of inflammatory arthritides that begin before the age of 16 and persist for at least six weeks, with no identifiable cause. JIA is classified into several subtypes including oligoarticular (affecting four or fewer joints), polyarticular (five or more joints, rheumatoid factor positive or negative), systemic (also known as Still disease, characterized by spiking fevers and rash), enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The disease primarily affects the musculoskeletal system, causing joint inflammation that leads to pain, swelling, stiffness, and reduced range of motion. If inadequately treated, chronic inflammation can result in joint damage, growth disturbances, and permanent disability. Systemic JIA can also affect multiple organ systems, including the skin (salmon-colored evanescent rash), lymph nodes, liver, spleen, and serous membranes (pericarditis, pleuritis). A serious complication of systemic JIA is macrophage activation syndrome (MAS), a potentially life-threatening hyperinflammatory condition. Uveitis (chronic anterior eye inflammation) is a significant extra-articular manifestation, particularly in oligoarticular JIA with positive antinuclear antibodies, and can lead to vision loss if undetected. The pathogenesis of JIA is multifactorial, involving complex interactions between genetic susceptibility (notably HLA associations and polymorphisms in immune-regulatory genes) and environmental triggers that lead to immune dysregulation. Treatment has been transformed by biologic therapies. Current management includes nonsteroidal anti-inflammatory drugs (NSAIDs), intra-articular corticosteroid injections, conventional disease-modifying antirheumatic drugs (DMARDs) such as methotrexate, and biologic agents including TNF inhibitors (etanercept, adalimumab), IL-1 inhibitors (anakinra, canakinumab), IL-6 inhibitors (tocilizumab), and T-cell co-stimulation modulators (abatacept). With early aggressive treatment, many children can achieve disease remission and maintain normal growth and development. Physical therapy and regular ophthalmologic screening are essential components of comprehensive care.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Juvenile idiopathic arthritis