Complications
JIA is a chronic disorder, which if neglected, can lead to serious complications. However, with regular follow-up and modern treatments, complications have reduced and outcomes improved. If inflammation is not treated, it can damage the joint, the cartilage and the bone. With the advent of modern therapies, these complications of JIA have become much less common.Children with JIA may have a reduced overall rate of growth, especially if the disease involves many joints or other body systems. This may be due to a combination of the disease itself, as well as its treatments, particularly corticosteroid use. Paradoxically, limbs where a large joint (such as the knee) is inflamed may have increased growth in the short term, leading to limb-length discrepancy (i.e. one arm or leg is slightly longer than the other). This is due to increased blood supply to the bony growth plates surrounding the inflamed joints. Bone density and bone strength may be reduced through a combination of inflammation, corticosteroid use and reduced physical activity levels. Other musculoskeletal complications may include joint contractures, muscle weakness or muscle wasting.Uveitis, if left untreated, can result in scarring, glaucoma, cataracts, and even blindness. Regular monitoring allows for early detection and treatment. Steroid eye drops are usually the first line treatment for anterior uveitis. However, other treatments – many of which also treat arthritis (e.g. methotrexate, biologics) – may be required to keep the inflammation under control, and to minimise steroid use over the longer term.
Children with systemic JIA usually present with fever and a classic rash and may become quite ill. Late effects of arthritis can include joint contractures (stiff, bent joints with loss of movement) due to joint damage; limb length discrepancies and muscle wasting. Children with JIA vary in the degree to which they are affected by particular symptoms. Extra-articular
Eye disease: JIA is associated with inflammation in the front of the eye (specifically iridocyclitis, a form of chronic anterior uveitis), which affects about one in six children with JIA. Eye involvement occurs most commonly in girls, those with only a few joints involved (oligoarthritis), and those with a positive anti-nuclear antibody (ANA). It usually follows the onset of arthritis or may be detected at the same time as arthritis; occasionally it may occur before joint involvement. The factors linking eye and joint disease are not clearly understood, and the two do not necessarily follow the same course. This complication is usually asymptomatic (without symptoms) and can occur when the joints are not active. It can be detected by an experienced optometrist or ophthalmologist using a slit lamp to look for inflammatory cells in the fluid inside the eye. Most children with JIA will require referral for regular slit lamp screening examinations. Poorly controlled chronic anterior uveitis may result in permanent eye damage, including blindness.Systemic JIA: children with the Systemic JIA subtype often experience extra-articular manifestations including fever, rash, enlarged lymph nodes, enlarged liver or spleen, serositis and anaemia.