When a smaller number of joints are affected (the oligoarticular type) there are four or fewer joints exhibiting arthritic symptoms with the larger joints being preferentially affected. Such children do not present as unwell although they may limp when questioned to walk. Arthritis may be confined to one hip but if the symptoms are limited to this joint then an alternative diagnosis should be sought as this is much more common, with Perthes disease a typical outcome. Arthritis over some time develops weakness and loss of bulk in the main knee muscles and a knee bend contracture partly due to tightening of the hamstrings. A discrepancy in length of legs can develop if arthritis affects only one leg.
With a larger number of joints affected, a minimum of five or more, the child has the many joint or polyarticular form of arthritis, with typically joints affected on both sides, a so called symmetrical involvement. A mild fever may be present and there can be significant muscle weakness and limitation of normal functioning if the joints have a severe limitation in their ranges of motion. A complete physical examination of the patient is vital to ensure that the diagnosis is juvenile arthritis, in what areas the physical limitations exist and which type of arthritis the patient is suffering from.
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 vital 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 perilous 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.
Surgery is not routinely indicated for most of these patients although joint injections with steroids may be employed for some. Polyarticular arthritis patients may suffer severe knee and hip arthritis which can be treated with knee and hip replacement once skeletal maturity has been reached and bone growth has stopped. Encouraging patients to be active is vital as resting for long periods is not helpful and more active patients do better.
Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about physiotherapy, physiotherapy, Physiotherapy Croydon, back pain, orthopaedic conditions, neck pain and injury management. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.
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