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Juvenile rheumatoid arthritis is the most common joint disease in children, and it is one of the one of the most common chronic diseases in children. Juvenile rheumatoid arthritis is termed "idiopathic," meaning medical science is still ignorant of its real causes. (In this article, the terms juvenile rheumatoid arthritis, juvenile idiopathic arthritis, and juvenile arthritis are used interchangeably.) A recently reported international study, however, has identified 17 genes associated with the disease that may confirm its causes.
How Do Doctors Diagnose Juvenile Idiopathic Arthritis?
Juvenile idiopathic arthritis is a condition that strikes before the age of 16. It causes joint pain for at least three months, and it may affect one or many joints in the body. When the condition only affects 1 to 4 joints, it is termed pauciarticular, and when it affects more than 4 joints, it is described as oligoarticular. The condition may be systemic, causing rashes and/or fevers, and in some children joint pain is not the most troubling symptom, the systemic effects are worse than the pain in the joints. When this form of arthritis causes fevers, they tend to spike at the same time every day and return to normal before the pattern repeats itself. Children who develop juvenile idiopathic arthritis may experience morning stiffness or a gelling phenomenon, stiffness after sitting too long in the same position.
What Are the Complications of Juvenile Idiopathic Arthritis?
Children who develop rheumatoid arthritis may experience few or many complications of the disease. There are more problems when the disease is systemic.
- Children who develop widespread arthritis have bones that age quickly. The spaces between the vertebrae of the spine may shrink so that the child is not as tall as would be expected for his or her weight, not because of fat, but because of contraction of the spine. Children who have arthritis in more than 4 joints may develop a condition called swan neck, making emergency intubation (insertion of a breathing tube) a difficult process.
- Teens and preteens who develop enthesitis-related arthritis, a form of inflammation of the entheses, the sites at which ligaments and tendons insert into the bone, may develop eye problems. They tend to develop photobia, a painful reaction to bright light, and conjunctivitis, swelling, redness, and crusting of the eyelid, although the condition seldom causes problems with sight.
- Children with limited arthritis, showing symptoms in just 1 to 4 joints, may develop a condition called uveitis. This is a condition of inflammation in the pigmented area in the center of the eye (that is, it does not effect the whites of the eyes). It is especially common in young girls who develop juvenile arthritis. It is important to take the child to the ophthalmologist at least every 4 months to detect eye problems early to prevent loss of sight.
- Arthritis that affects just one leg can lead to premature closing of the growth plates in the joints, so that the arthritic leg is shorter than the non-arthritic leg, or it can lead to excessive growth of blood vessels in the joints of that leg, so that the arthritic leg is longer. Often this problem is not detected until the joint is treated.
And in a few cases juvenile arthritis can cause aberrations in the immune system that interfere with the blood's ability to clot, cause the blood to accumulate excessive amounts of iron, and even interfere with breathing and cause inflammation around the heart.
Treatment of juvenile idiopathic arthritis is complicated, but the recent gene discoveries may help.