Chronic Arthritis of Childhood – Part Two
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 asked 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.
Neck changes can include a limitation of cervical extension which is often not symptomatic but is an important issue because it indicates that the neck has arthritic changes within it which can progress to the joints partially dislocating in the high neck, a dangerous neck syndrome. The posterior neck structures may also fuse themselves due to the inflammation. The joints of the jaw (temperomandibular joints) can be affected by the arthritis process and this reduces the amount of growth in the jaw and limits the person''s ability to open their mouth wide. Eyes can also be affected.
Juvenile arthritis and other complex conditions are best managed by a specialised multidisciplinary team due to the numerous problems which patients have to do with family and patient education and schooling, drug treatments, physiotherapy and occupational therapy. It is rarely if ever successful to give isolated treatments to this patient group. Reviewing patients at regular intervals allows the drug treatments to be fine tuned towards a reduction in the morning stiffness and towards fewer affected joints until no symptomatic joints remain. A typical team to manage these conditions may include a physiotherapist, occupational therapist, social workers, a paediatric rheumatologist and nurse.
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 important as resting for long periods is not helpful and more active patients do better.
Author: Jonathan Blood-Smyth