The Medical Minute: Arthritis in children

By Barbara E. Ostrov

Did you know that kids get arthritis too? Arthritis is not just a disease of older individuals.

Many people do not realize that arthritis affects children of all ages. Juvenile arthritis causes pain, stiffness and inflammation of one or more joints in children 16 years of age or less. Nearly 300,000 children in the United States are affected by some type of juvenile arthritis. To educate the public more about rheumatic illnesses in children, July has been declared National Juvenile Arthritis Awareness Month.

According to the Arthritis Foundation, there are 100 types of arthritis, many of which affect children as well as adults. While some of these disorders are very similar in adults and children, other types of arthritis and the risk of certain complications are quite different in pediatric patients.

The most common rheumatic diagnosis in children is juvenile idiopathic arthritis (JIA). In older medical literature one would often read about “juvenile rheumatoid arthritis” but the terminology was changed, in part, to make it clear that the childhood forms of arthritis are not the same as adult rheumatoid arthritis (RA).

Several subtypes of JIA are found in children. Some of the youngest patients with JIA (2 years of age on average) often have arthritis only in a few joints (oligoarticular JIA). Treatment might include cortisone shots into joints, NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen or naproxen, and occasionally, stronger medications called DMARDs (disease modifying anti-rheumatic drugs). These children are at risk of developing silent, chronic eye inflammation (uveitis), which may cause vision loss if not detected early. In these small patients, eye exams as well as pediatric rheumatology visits must be performed at frequent intervals to make sure treatment is tailored to each child’s disease.

In one third of children with arthritis, many joints become inflamed (polyarticular JIA subtype). When a teenager has polyarticular JIA, the disease may resemble adult RA. In adolescents with polyarticular JIA, or about 10 percent of our patients, severe joint damage may occur. Medications such as NSAIDs, DMARDs and cortisone shots can help, but only up to a point. Twenty years ago such children had a 50-50 chance of severe joint damage by the time they reached adulthood. Nowadays, with aggressive treatment, including combinations of medications plus the new Biologic therapies (such as etanercept, adalimumab and abatacept), we are able to control the inflammation and prevent joint damage in the majority of patients. Close monitoring for side effects of the treatments as well as complications of the arthritis is an important part of the care of these children.

There is a more severe form of JIA with body-wide inflammation that develops in about one of five children with JIA. This subtype is called “systemic JIA.” A similar, rare illness can occur in adults, but is 100 times more common in children. Rash, high spiking fevers, swollen organs and severe inflammation on laboratory testing are detected. These children may be quite ill and often are put through a series of tests to rule out infections, rheumatic fever, and cancer before the diagnosis can be confirmed. The same medications can be used to control the systemic and joint inflammation but these children need to be monitored closely for complications of the liver, heart or blood. The severity of the arthritis determines the long term outcome of these children.

Psoriasis is a common skin condition in children and causes arthritis in about one out of five patients with this rash -- “psoriatic arthritis.” Finger, toe, knee, hip or spine inflammation are common with psoriatic arthritis. Spine inflammation and tenderness of tendons and ligaments (“enthesitis”) is a feature of psoriatic arthritis as well as several other types of arthritis in children.

There are several illnesses which can cause body-wide inflammation due to an overactive immune system (autoimmune disease) and some diseases are genetic in nature (“autoinflammatory disorders”). Systemic lupus erythmatosus (SLE) is a well known autoimmune disorder that can cause rashes, inflamed heart, lungs, kidney and/or brain as well as arthritis. Ninety percent of the time, SLE occurs in females. Twenty percent of patients develop their first signs and symptoms of SLE between puberty and 18 years of age. Autoimmune disorders can affect the muscles and skin, blood vessels or liver as other examples. Some of these are rare illnesses, with fewer than 100 new cases nationwide per year, in contrast to JIA, which is diagnosed in thousands of children each year.

Ideally, children with autoimmune and rheumatic diseases will have a pediatric rheumatologist as part of their care team. These physicians are specially trained pediatricians are able to diagnose and treat children with these common and rare disorders. Unfortunately, in the United States there are only about 250 board-certified pediatric rheumatologists. Several states have no pediatric rheumatologist at all. In 2010, we are able to better diagnose and treat children with rheumatic diseases but do not always have the trained specialists to do so. Manpower issues will be a concern for primary care but also specialty care into the future.

Barbara E. Ostrov, M.D., is professor of Pediatrics and Medicine in the Division of Pediatric Rheumatology and Rheumatology at Penn State Hershey Children’s Hospital, Penn State Milton S. Hershey Medical Center.

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Last Updated July 13, 2010