Chronic Arthritis of Childhood – Part Two

The fewer joint affected type of arthritis (oligoarticular) is characterised by having four or fewer joints affected, with the larger joints more typically affected such as the knees and ankles. These children usually appear well even though they may limp on walking. If only one hip seems affected this is very unusual for this type of arthritis and a different condition such as Perthes disease should be suspected. If the joints, such as the knees, are affected over a long period then the large extensor muscles of the thighs can weaken and waste, with tight hamstrings leading the flexion contractures of the knees. If the legs are affected asymmetrically then the length of the legs can develop a discrepancy.

The many joint affected type of disease (polyarticular) is characterised by having at least five joints affected, typically in a symmetrical pattern with the same joints affected on both sides. The child may have a low grade fever and if there are significant limits of joint movement this is associated with weakness of the relevant muscles and decreased normal function. A thorough physical examination of the child is very important for the correct diagnosis of juvenile arthritis as this will indicate where the problems lie and which kind of juvenile arthritis the patient has.

Settling on the diagnosis of juvenile arthritis depends on a joint showing an effusion which is the presence of inflammatory fluid within the joint, along with other symptoms and signs such as warmth, redness, limited range of motion and pain. Some joints may have an effusion which is not apparent such as the hip, but they can still show limited movement of the joint and pain. It may not be possible to establish the diagnosis of juvenile arthritis as the fever and rashes may come on initially without the arthritis at the time, with the arthritis appearing later by several months. Enlargement of lymph nodes and the liver and tenderness of muscles may be evident.

A symmetrical occurrence of arthritic changes in the major weight bearing joints and in the hand small joints is a typical finding in the polyarticular form of juvenile arthritis. The cartilage lining the joints can narrow in thickness, develop eroded areas and can form a fusion in some cases bridging the joint. Chronic changes over longer periods can include chronic joint effusions and thickened synovial membrane, subluxed joints, stiff joints and contractures, enlargement of the bone around the joint and bony deformities (often of fingers). Bone density can also reduce around the joints and the cartilage thinning can cause joint space narrowing.

A reduction of extension in the neck may not produce any symptoms but it is important to identify this as it can indicate arthritic changes in the cervical spine which can lead to partial dislocation (subluxation) of the upper neck bones, a potentially dangerous situation. The neck bones can also fuse together along the posterior structures. The jaw joints, the tempero-mandibular joints, may also be affected and lead to reduced amount of growth in the lower jaw with inability to open the mouth as wide as normal. There may also be involvement of the eyes in the inflammatory process.

The management of children with juvenile arthritis works best as a team process as many aspects need to be considered such as medication, physiotherapy, occupational therapy, family education and school function. Individual treatments on their own will not be successful. Seeing the patient for regular examinations allows the medication to be regularly reviewed and changed, aiming at a reduction in morning stiffness and the number of joints involved until the number of affected joints drops to zero. The team will likely consist of a paediatric rheumatologist, a nurse, a physiotherapist and occupational therapist and social workers to help with family and school issues.

Surgical care is not typically engaged although joint injections of steroids may be useful in some cases. Joint replacement can be used for hip or knee arthritis in patients with polyarticular arthritis but is usually delayed until skeletal maturity means bone growth has stopped. Activity is usually encouraged as long term rest is unhelpful and increased activity indicates a better outcome.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and Croydon Physiotherapists. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.