Juvenile chronic arthritis
Statistics show that approximately one child in 1,000 is affected by juvenile chronic arthritis. It can occur in children at any age, but first appears more commonly between the ages of 2 and 6 years. There are many different types of juvenile arthritis, the most common being juvenile rheumatoid arthritis.
What causes juvenile rheumatoid arthritis?
Juvenile rheumatoid arthritis is an autoimmune disorder. This means that the body mistakenly attacks some of its own cells and tissues. It is not known why this occurs in juvenile rheumatoid arthritis, but some scientists suspect that an environmental factor such as a virus may trigger the condition in genetically susceptible children.
The main difference between juvenile and adult rheumatoid arthritis is that more than half of the children affected grow out of it, while adults usually have symptoms for life. Another difference is that, according to US statistics, fewer than half of all children with the condition test positive for a particular kind of antibody in their blood called rheumatoid factor (RF), whereas about 70-80 per cent of adults with RA do test positive.
Different kinds of juvenile rheumatoid arthritis
There are 3 main types of juvenile rheumatoid arthritis.
Pauci-articular arthritis is the most common form, and occurs in about half of all children with juvenile rheumatoid arthritis, notably in girls under the age of 8. Pauci-articular arthritis typically affects 4 or fewer joints, usually the larger ones such as the knees. It can be accompanied by stiffness, particularly in the morning, causing the child to limp.
Between 20 and 30 per cent of children with pauci-articular arthritis may also be susceptible to eye diseases such as iritis (inflammation of the iris) or uveitis (inflammation of the inner eye or uvea). For this reason, these children should also be examined regularly by an ophthalmologist. The second important problem with pauci-articular arthritis is that it may cause the bones in the legs to grow at different rates, causing a limp. This may damage the knee and hip leading to premature wear and tear on these joints.
Polyarticular arthritis affects approximately 30 per cent of all children with juvenile rheumatoid arthritis. It is characterised by 5 or more joints being affected, most commonly the smaller joints in the hands and feet. Children with polyarticular arthritis often have a more severe form of the disease.
Systemic arthritis (also known as Still's disease) affects approximately 10 per cent of all children with juvenile rheumatoid arthritis, according to US statistics, and is characterised by joint swelling in combination with fever and a pink rash that comes and goes. The joints may not start to swell until some months or years after the fevers begin. It may also affect internal organs such as the liver, heart, spleen and lymph nodes, and anaemia (low levels of the red blood cells that carry oxygen in the body) is common. While systemic arthritis tends to abate of its own accord, a small percentage of these children can have severe arthritis that continues into adulthood.
Diagnosis, treatment and outlook
Symptoms include limping, stiffness, reluctance to use an arm or leg, decreased activity level, persistent fever, and joint swelling. Joint swelling or pain must have been present for at least 6 weeks for the doctor to consider juvenile rheumatoid arthritis as a diagnosis. Along with a detailed medical history, thorough physical examination and symptom evaluation, blood tests and X-rays may be necessary to confirm the diagnosis.
Early diagnosis and treatment are essential, with the main aim being to minimise damage by keeping the joints moving, the muscles strong and the limbs in a good position. This may involve a combination of medication, physical therapy and exercise in order to relieve the pain and inflammation and to slow down or prevent joint destruction.
NSAIDs (non-steroidal anti-inflammatory drugs) can relieve the pain for many children, but more severe cases may require medications such as sulfasalazine or methotrexate, or one of the newer medications for rheumatoid arthritis such as etanercept (Enbrel). While steroids can be very effective, it is important that they are not taken for prolonged periods as they can inhibit children’s growth and cause weak bones. Steroids can be taken by mouth or, if only one joint is affected, injected into the joint.
The outlook for children with arthritis is generally very good. Most children with pauci-articular arthritis tend to completely recover and grow up without obvious disability. Those with systemic arthritis tend to have either complete recovery or may develop persistent polyarticular arthritis. Of those with polyarticular disease, some recover while others have arthritis persisting into adulthood.
Promoting optimal growth, physical activity, and social and emotional development in your child will help to ensure that your child will lead a normal, healthy life.
Last Reviewed: 19 June 2009
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