To help distinguish JRA from adult arthritis, the term that is currently being used is juvenile idiopathic arthritis (JIA). The official designation for either JRA or JIA means that the inflammation begins before age 16.
What causes JRA?
The assumption is that your immune system starts attacking joint tissue. But the why and how—and why in some people it affects only a few, rather than many joints—is completely unclear.
What are the different types of JRA?
First, there is pauciarticular, which involves four or fewer of the larger joints, most commonly the knees and ankles. This disease usually begins before age 5, and the peak incidence is between the ages of two and three.
Then there is a form called polyarticular arthritis that, while it has its onset before age 16, behaves like adult-pattern rheumatoid arthritis and has an immunologic marker called rheumatoid factor.
Third, and perhaps the hardest to take care of, is systemic-onset juvenile arthritis, which is associated with fevers, a rash and sometimes an enlarged liver, spleen or lymph nodes. There are fevers once or twice a day that spike up and down. And the rash is also a fairly typical kind of rash that is seen at the time of the fever. Sometimes these patients don't even have arthritis at the beginning, and they are often diagnosed with a fever of unknown origin until they eventually develop joint symptoms. While some of these kids respond very nicely to medication, there is a group that is very resistant to treatment.
Additionally, there is arthritis that is associated with psoriasis. This arthritis is often a mix of one finger, one ankle, one knee or something like that. These kids don't always have the skin condition psoriasis; they usually have some nail changes like "nail pitting." This type of arthritis is inherited, so if the child has arthritis, those odd nails and a relative that has psoriasis, they may have psoriatic arthritis.
What are the symptoms of JRA?
Some of the kids have a significant amount of pain, and pain in the joint could be many other serious things that shouldn't be ignored. But more often than not, the kids are not complaining of pain. It's important to realize that the kids that usually wind up to have JRA have relatively little pain until you try to force them to straighten the leg or force them to bend the leg all the way. Then it hurts.
If the arthritis affects the legs, one common symptom is gait change. They do have a certain amount of pain when you examine them, but in real life they may hold an affected knee slightly bent so it's more comfortable. So when you walk with your knee slightly bent, you will limp. The parents will often say, "They're walking like a little old man."
How is the diagnosis of the type of JRA made?
When you see a pediatric rheumatologist, the visit is usually quite long. The doctor will need an extremely detailed history: "When did it start? How long? What time of day is the worst?"
Then you do an exam. You're looking for warmth, swelling and loss of motion in a joint. Then we do a few blood tests to see if the white blood cell count is high, whether they are anemic, whether they have high platelet levels—all of these are signs of inflammation.
However, children with pauciarticular juvenile arthritis often have completely normal blood work. As a matter of fact, if the blood work is very abnormal, you start to doubt that diagnosis. Generally, pauciarticular arthritis is diagnosed when the history fits, the pattern fits, the exam fits, and we can't find any other reason—it's a diagnosis of exclusion.
There is also a test for rheumatoid factor, but that's positive only in one small subclass of patients. Ninety percent of kids with JRA have a negative rheumatoid factor, so we almost expect it to be negative. In fact, many times, if the pattern of the arthritis doesn't look like it's rheumatoid factor positive, the test isn't even done.
What can JRA be confused with?
Kids can get big, fat, swollen joints just after any kind of virus or cold, and even if they get Lyme disease. So, we first ask if the child has been sick or possibly in a tick-infested area.
What is a common treatment regimen for JRA?
Treatment depends upon both the type and the severity. There is no true treatment algorithm that we all follow. So you may go to five different rheumatologists, and you will probably get similar approaches, but not necessarily identical ones.
If this has only started a week or two ago, and it hasn't been going on for six months already, I will start the child on a simple anti-inflammatory drug, such as naproxen (Aleve) or ibuprofen (Advil, Motrin). But these drugs are prescribed at anti-inflammatory doses, which are much higher than the over-the-counter dose on the bottle and are given around the clock—it's not for pain, but to get rid of inflammation, and it can take four weeks or more to kick in.
After about four to six weeks, if they haven't made a lot of progress, and it's a child that has pauciarticular juvenile arthritis with only one or two joints involved, the majority of pediatric rheumatologists recommend a steroid shot directly into the joint. Almost all the children will respond immediately to this. But most of them will respond for only six months, and some will only respond for one month. For these children, you have to go to step three with them.
The next drug, methotrexate, is used if they either don't respond, the response doesn't last long enough or they have too many joints involved for the shots (too many joints is up to the parent or the physician to determine). While methotrexate is known as a cancer drug, at small doses it can reduce inflammation. It is given orally or injected at home, once a week. Kids may sometimes feel nauseated the day after, but they are in the minority. Between 50 and 70 percent of kids will respond to methotrexate.
Are the new biologic treatments effective for JRA?
Some doctors will, instead of using methotrexate, go right to one of the newer biologics, like etanercept (Enbrel), which is approved for use in children over four years of age. The big downside of entanercept, in my opinion, is that it is only approved for twice-a-week injections, and it cannot be given orally.
Do kids need to take these drugs for the rest of their lives?
That is an excellent question to which we have no answers. There really have been very few long-term studies, and many of the statistics we do have are from before we started to use methotrexate and the biologics.
The statistics that do exist show that if you have the pauciarticular type of juvenile rheumatoid arthritis, somewhere between 50 and 70 percent of those kids will eventually outgrow it. If you have rheumatoid factor negative polyarticular or systemic onset juvenile rheumatoid arthritis, there is only between a 30 to 50 percent chance of you outgrowing it. If you have the rheumatoid factor positive type, the odds of that going away are extremely low, probably less than 10 percent. But that's the smallest group, so we don't have much long-term data. We have no data at all for psoriatic arthritis.
Is physical therapy helpful?
Physical therapy is extremely important, as well as occupational therapy. There is a lot of hand involvement with arthritis and the occupational therapists try to maintain range of motion. Having a joint swollen and being held in a slightly flexed or bent position will cause tendon shortening, so even if the arthritis is completely under control, kids may not have full extension, and it is important to get full range of motion.
What is the outlook for families dealing with JRA?
We get better and better treatments every year. Back in the old days, many of these kids wound up in wheelchairs.
Today, most parents can assume that their children will lead a totally normal life. The only difference is that they may have to remember to take some medication, as with any chronic disease. But these kids are going to run, play and jump just like the other kids.
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