Juvenile Idiopathic Arthritis
What Happens
The course of juvenile idiopathic arthritis (JIA) is unpredictable, especially during the first few years after a child is diagnosed. JIA, also called juvenile rheumatoid arthritis (JRA) or juvenile chronic arthritis (JCA), can be mild, causing few problems. Symptoms can worsen or disappear without clear reason. Eventually the pattern of symptoms becomes more predictable. In general, children with JIA have one or a combination of symptoms including joint pain, joint swelling, and joint stiffness early in the course of the disease. Many children experience sleep disturbances, including difficulty falling asleep and frequent night awakenings.4 Most children have good and bad days.
Of all children with JIA, 3 to 4 out of 10 children will have serious long-term disability.5 While the overall long-term outlook for children with JIA is often good, symptoms of the disease can continue into adulthood. Long-term disability may range from occasional stiffness, the need for pain medication, limits on physical activity to ongoing arthritis, and the need for major surgery such as joint replacement. However, for most adults who had JIA as children, any long-term problems tend to be mild and do not affect their overall quality of life. For instance, they may not be able to play certain sports, but their activities are not otherwise limited.
A child's long-term outlook is influenced by the type of juvenile idiopathic arthritis he or she has. While a child with pauciarticular JIA (4 or fewer joints affected) has a good long-term outlook other than eye disease risk, a child with polyarticular JIA (5 or more joints) or systemic JIA (whole-body symptoms) is likely to have more long-term problems.6
Pauciarticular JIA (oligoarthritis)
About 40% to 60% of all children affected by JIA have the pauciarticular form.5 In this form of JIA, some children have joint damage that shows on X-rays within 5 years. Children with pauciarticular JIA (oligoarthritis, meaning "few joints") have a 40% to 50% chance of continuing to have disease as an adult.5
- Most children with pauciarticular JIA have 4 or fewer joints affected (persistent oligoarthritis).6
- About 20% go on to have 5 or more joints affected over time (referred to as extended oligoarthritis, resembling polyarthritis).6
- Children with pauciarticular JIA are at increased risk of having vision loss caused by inflammatory eye disease.6 Eye disease develops in about 20% of children with pauciarticular JIA.7
- Some children with pauciarticular JIA have uneven leg bone growth, resulting in legs of different length and muscle wasting.5
Polyarticular JIA (polyarthritis)
Polyarticular JIA (polyarthritis) affects many joints—often the knee, hip, wrist, elbow, and ankle joints—and may affect the small joints in the hands and feet. This type of JIA is more severe than pauciarticular JIA because it affects more joints and tends to get worse over time. Joint damage can be seen on X-ray within 2 years in some children. About 25% to 35% of children affected by JIA have the polyarticular form. Of these children, about 50% to 70% will have active disease that continues into adulthood.5
For a child with polyarticular JIA, the following factors are signs of increased risk of developing joint deformity and disability as an adult:6
- Onset of disease after 10 years of age
- Joint problems in hands or feet early in the course of the disease
- Rapidly progressing joint damage (erosion)
- Chronic symptoms that don't respond to treatment
- Significant whole-body (systemic) symptoms, such as fever, fatigue, and appetite loss
- Bumps under the skin (rheumatoid nodules) over pressure points (such as the elbow or back of the heel)
Of all children with juvenile idiopathic arthritis, only about 5% to 10% have polyarticular JIA with the presence of the rheumatoid factor (RF) antibody in their blood.5 Normally, antibodies are produced by the immune system to help destroy and eliminate invading bacteria and viruses that can cause disease. However, RF is an antibody that can attach to normal body tissue, resulting in damage. RF-positive polyarticular JIA is thought to be identical to adult rheumatoid arthritis. The risk of joint deformity is highest (about 50% likelihood) in children with RF-positive polyarticular JIA.8
Systemic JIA
About 10% to 20% of children affected by JIA have the systemic form.5 Usually, a child with systemic JIA will have fever spikes and a rash for weeks to months before arthritis joint pain begins. Whole-body (systemic) symptoms (such as fatigue and loss of appetite) and enlarged lymph nodes, liver, and spleen may come and go during the first years of the disease. About a third of children with systemic JIA develop heart and complications, most often early in their illness.8
Some children with systemic JIA will have joint damage visible on X-ray within 2 years. About 50% to 70% of children with systemic JIA will continue to have active disease as adults.5 Systemic symptoms rarely last more than 5 years, while joint symptoms can last 10 years or more.6
Complications
Complications associated with JIA can include:
- Inflammatory eye disease, such as uveitis. Children and adults with this condition can develop cataracts, glaucoma, corneal degeneration (band keratopathy), or vision loss.
- Growth abnormalities, such as unequal leg lengths, an imbalance in growth of the jaw, and temporary delay in breast enlargement.
- Joint damage. This is common in the polyarticular form of JIA and can occur early. About 30% of children with JIA will have some level of disability that continues into adulthood.7 Children with the pauciarticular form of JIA seldom develop significant disabilities.
Some children with polyarthritis develop arthritis in the neck that can cause the neck bones to fuse together. A child who has arthritis in the neck may need to wear a neck (cervical) collar when riding in a vehicle to reduce the risk of neck injury during a sudden stop or accident.
Complications of systemic JIA include heart or lung problems, such as pericarditis, pleuritis, or pericardial effusion. A rare lung complication is the formation of scar tissue in the lungs (pulmonary fibrosis).
 Go to previous section |  Go to top of page |  Go to next section |
| Author: | Douglas Dana Shannon Erstad, MBA/MPH | Last Updated: August 30, 2006 |
| Medical Review: | Adam Husney, MD - Family Medicine Michael J. Sexton, MD - Pediatrics Ross E. Petty, MD, PhD, FRCPC - Pediatric Rheumatology | |
 | ||
