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 childs ability to fully participate in activities and undertake usual tasks such as those used for self-care. In some JIA subtypes, more non-specific symptoms of being unwell may be present, such as lethargy, fatigue and poor appetite.
Pain has been found to negatively impact all aspects of quality of life and is associated with a reduction in physical, social and emotional functioning. Children who have higher levels of pain tend to have reduced levels of socialization, school attendance and participation in activities. Increased pain is also correlated with poor sleep and higher fatigue in children with JIA. The causation of pain in JIA is multifactorial. There are disease-related factors, which relate to the inflammatory process, and anatomical or biomechanical changes that are associated with joint swelling and joint disease. There are psychological factors around dealing with stress, coping with a chronic illness and managing anxiety or depression which can influence the perception of pain and the degree of functional impairment. There are also social factors, which relate to family and peer relationships, parental distress and social and financial supports. Given the waxing and waning nature of JIA, childrens physical abilities, pain and mood can change during periods of flare or remission. Coping with chronic illness during childhood and adolescence is associated with significant stress that can put children at risk for emotional or behavioural distress and can interfere with compliance and adherence to treatment regimes. Managing JIA can be a challenge and it is important to have a toolbox of skills, supports and strategies to draw upon to manage the ups and downs of having a chronic illness. There are many things that can help children with JIA to grow up to have full and active lives.