Arthritis in children

It is hard to accept that children, even babies, can be affected by arthritis. In fact one in 1000 children will have arthritis during the early years of their life. It commonly is diagnosed between ages one and four, but can occur at any age. Sometimes it is called Still's disease.

Arthritis may be difficult to diagnose in a young child. Often children do not complain specifically about pain but just seem unhappy or grizzly and off their food. Swelling in a joint may also be difficult to detect. A limp or reluctance to walk or to use both hands normally when playing may be the first signs of arthritis. When a joint is inflamed, it is more comfortable to hold it bent, and this can be another sign as well as stiffness first thing in the morning.

There are several different types or patterns of arthritis which occur in childhood.

Pauci-articular (or oligo-articular) JCA

This is the most common sort of juvenile chronic arthritis (JCA), accounting for about 50% of diagnoses. It affects four or less joints and can be called mono-articular JCA if only one joint is affected (most often the knee). It more commonly affects children under the age of 5 and girls more than boys. The disease may also be associated with inflammation of the eyes, especially if blood tests show the presence of an antibody called antinuclear antibody or ANA.

As this disease only affects a small number of joints, treatment is usually with corticosteroid injections into the joints and/or oral NSAIDs. The development of the disease is generally excellent with 70% of children going into remission after 3-4 years. The remaining group progress to polyarticular disease.

Polyarticular JCA

This disease affects more than 4 joints. It often involves the joints of the hands and feet and produces pain, swelling and stiffness of the joints. The flexor tendons of the hands may also become inflamed and there is often difficulty with writing, especially if the wrists are involved. Involvement of the lower limbs may result in difficulty with walking.

Children will often feel unwell, especially when the disease is active. NSAIDs will be used, as well as disease modifying anti-rheumatic drugs (DMARDS) or immunosuppressive drugs to help prevent serious joint damage.

Only a small number of children (about 5%, mostly older girls) are found to be rheumatoid factor positive. This is called JRA (juvenile rheumatoid arthritis) and for these children it is important that the disease modifying drugs are begun early to prevent joint damage.

Systemic JCA

This disease is often the most difficult to diagnose, especially as Arthritis may not be present at the beginning of the illness. It can affect children at any age, but is most common in the under 5s. It usually starts with a high fever more troublesome in the evenings than during the day. A red blotchy sometimes itchy rash often comes and goes with the fever, more commonly seen on the arms and legs. Enlargement of the glands may also occur.

There are no specific tests to diagnose systemic JCA, but blood tests can eliminate other conditions. Treatment is likely to be with high doses of NSAIDs and oral or intravenous corticosteroids, DMARDs, or immunosuppressive drugs as required to control the disease.

Juvenile spondyloarthropy

This disease accounts for less than 10% of JCA diagnoses. It particularly affects teenage boys causing arthritis in the hips, knees or ankles. There may also be inflammation at the tendons where they connect to the bone such as the Achilles tendon in the heel.

This disease is often accompanied by acute inflammation of the eye. It may also develop into inflammation of the sacroiliac joints at the base of the spine. 90% of children with spondyloarthropathy carry the HLA B27 antigen which can be detected by a blood test.

Treatment is again with NSAIDs and corticosteroid injections into the joints and DMARDs.

Treatment

To avoid joint damage and many of the other affects of JCA, treatment must be continued even while the disease is active. It will include medication, physiotherapy, exercise, rest and may also include the use of splints to help joints keep the best position and movement possible. Special shoes and insoles help to support the foot. Prevention of joint contractures is a prime aim of physiotherapy for JCA.

For children, it is essential they be given great support, encouragement and understanding to cope with the pain and physical disability while trying to maintain as normal a life as possible. Arthritis is a disease that is unseen and can vary from day to day, and there is a lot of misunderstanding of its effect on a child's life.

Original material provided by Arthritis New Zealand. Reviewed by everybody, July 2005.