Arthritis means inflammation within the joint, and is usually recognised by swelling, pain, stiffness and restricted joint movement. Symptoms of<unk>  vary from individual to individual. This is mainly because<unk>  is an umbrella term for several subtypes of<unk> , which differ according to the number of affected joints, severity of disease and presence or absence of inflammation in other parts of the body. The key clinical feature in<unk>  is persistent swelling of the affected joints. Any joint can be affected, but large joints such as the knee and ankle are most commonly involved. Involvement of small joints of the hands and feet is more likely when many joints are affected ('polyarthritis'). Swollen joints may also feel warmer to touch. Swelling may be difficult to detect clinically, especially for joints such as those of the spine, sacroiliac joints, shoulder, hip, and jaw; imaging techniques such as ultrasound or MRI can be very useful to identify the inflammation. Joint pain is an important symptom, although some children experience minimal or no pain with their arthritis. In these children, the first sign of arthritis may be limping, especially in the morning. Young children are often very good at changing how they move when they have joint pain: they learn to move so that it does not hurt. For example, a child will not push up using an inflamed wrist when climbing, instead putting their weight through the forearm. Morning stiffness that improves later in the day is a common feature (this implies inflammatory-type joint pain versus mechanical-type joint pain). Swelling and pain usually result in limited movement of the affected joints, for example a knee held bent causing a limp, or being unable to make a full fist. Limited movement may reduce a child's ability to fully participate in activities and undertake usual tasks such as those used for self-care. In some<unk>  subtypes, more non-specific symptoms of being unwell may be present, such as lethargy, fatigue and poor appetite. Children with systemic<unk>  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<unk>  vary in the degree to which they are affected by particular symptoms. Extra-articular Eye disease:<unk>  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<unk> . 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<unk>  will require referral for regular slit lamp screening examinations. Poorly controlled chronic anterior uveitis may result in permanent eye damage, including blindness. Systemic<unk> : children with the Systemic<unk>  subtype often experience extra-articular manifestations including fever, rash, enlarged lymph nodes, enlarged liver or spleen, serositis and anaemia. Complications<unk>  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<unk>  have become much less common. Children with<unk>  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 (eg methotrexate, biologics) – may be required to keep the inflammation under control, and to minimise steroid use over the longer term. Long term steroid use can cause contribute to the development of cataracts. Macrophage activation syndrome (MAS) is a severe, potentially life-threatening complication that can occur in patients with the systemic subtype of<unk> . MAS involves uncontrolled activation of the immune system, sometimes referred to as a 'cytokine storm', which can present with a sepsis-like picture of fever, rash, enlarged liver and spleen, enlarged lymph nodes and cardiorespiratory compromise. It is recognised by a series of characteristic changes in laboratory parameters, including a high ferritin and a paradoxically low erythrocyte sedimentation rate.
Juvenile idiopathic arthritis
Kawasaki disease
Systemic-onset juvenile idiopathic arthritis
Reactive arthritis
Psoriatic arthritis
Rheumatoid arthritis
Relapsing polychondritis
Inflammatory arthritis