Have your child sit on the floor with legs together and outstretched. A normal child can put the back of his or her knee flat on the floor so you cannot even slip a piece of paper underneath it. If you can see a space under the knee or slip your fingers under it, there is a flexion contracture.
Children who continually favor the leg that hurts will eventually develop a weakening (atrophy) of the muscles in that leg. As with flexion contracture, physical therapy can help prevent this problem.
An arthritis-affected knee can appear larger than a normal knee because of the muscle atrophy or bony overgrowth, but it can also be larger because of fluid in the joint.
Eye involvement is the other significant complication of pauciarticular JA. Although we do not fully understand why the eye is affected, the presence of a positive ANA is strongly correlated with the risk of eye disease (see Chapter 6). The eye disease, called uveitis or iridocyclitis, takes the form of inflammation of cells in the anterior chamber of the eye. The inflammation can lead to damage to the iris with scarring and irregularity of the pupil. These scars are called syn-echiae (see Fig. 5-1). Because the eye disease is usually painless and may go unnoticed for a long period, it is recommended that an ophthalmologist screen ANA-positive children every three months. Although the risk of eye involvement is lower in ANA-negative children and in children with polyarticular-onset disease, it may still occur, and ANAnegative children should be screened every six months. Note that it is rare for children with pauciarticular arthritis to develop new eye disease after ten years of age.
On occasion I see children who were diagnosed with pauciarticular-onset disease many years before who now have stiff necks. It is well recognized that children with polyarticular-onset disease may develop cervical fusion over time, causing the stiff neck. Sometimes there is no real complaint from the child, and the finding is noted only on X-rays. It is unclear whether cervical fusion is a complication of true pauciarticular-onset arthritis or whether these are children whose disease should have been characterized as polyarticular initially.
Some children with pauciarticular-onset arthritis eventually develop problems with the temporomandibular joint, which allows the jaw to open and close. It can present as difficulty opening the mouth widely, difficulty chewing, or chronic headaches on one side of the head. Often this occurs in children who are also found to have neck pain. How these two findings are interrelated and their
relationship to true pauciarticular-onset arthritis is unclear. Temporomandibular joint involvement also occurs in some children with spondyloarthropathies.
Was this article helpful?