The Medical Minute: What juvenile idiopathic arthritis means for kids

Juvenile idiopathic arthritis (JIA) is one of the most common rheumatic diseases in childhood. Estimates of the number of children affected at any one time vary greatly, ranging between 16 to 150 per 100,000 children. JIA has been known by different names over the years. Previously, “juvenile rheumatoid arthritis” and “juvenile chronic arthritis” were terms that were used to describe this broad class of diseases. It is an inflammatory arthritis, present for six weeks or longer in a child 16 years of age or less. Inflammatory arthritis refers to inflammation, and usually swelling, of a joint. This is in comparison to osteoarthritis, which is usually seen in older individuals from “wear and tear” damage to a joint.

There are different types of JIA, including systemic JIA (kids usually have rash, fever, abnormal labs, and swollen joints), polyarticular JIA (this involves five or more joints), oligoarticular JIA (involving four or fewer joints), psoriatic JIA (swollen joints with psoriasis, having an entire digit swollen, pitting of the nails or nail changes, or having a first-degree relative with psoriasis), and arthritis related to inflammation of entheses (known as enthesitis).

An enthesis is where a tendon, muscle or ligament inserts into a bone. Common area of enthesitis that give kids trouble in this type of JIA include under the knee and at the base of the Achilles tendon, near the heel. Here in Central Pennsylvania, we see a lot of enthesitis-related JIA. This is likely due to the higher risk of this type of JIA in people with German heritage. Often, children have months of foot, ankle, or knee pain which is worse with high-impact exercise. This type of exercise can exacerbate the inflammation of the involved entheses. Diagnosis may be delayed because no swelling is seen or it may be assumed to be injury related.

The cause of JIA is different depending on the type of disease. In general it is an autoimmune disease, one in which an overactive and misdirected immune system “attacks” itself, with complex genetic and potential environmental triggers. JIA requires therapy and the involvement of a pediatric rheumatologist. If an individual’s disease is mild, anti-inflammatories may be helpful. Due to its autoimmune nature, more severely affected individuals require medications that target the immune system. It is fortunate that within the past 15 years, more effective medications have become available for use in people with autoimmune diseases, such as JIA, to control disease and help prevent or minimize disabilities.

Children with JIA often feel frustrated in their struggle to be as normal as possible. If you would like to help, contribute, or just learn more about JIA, check out www.liveonedayforcarra.org, http://www.arthritis.org/juvenile-arthritis.php and http://www.printo.it/pediatric-rheumatology/information/UK/1.htm online.

Provided by Pennsylvania State University