Many people think of arthritis as a condition that affects people in their middle or older years. But young people can get it too, and an estimated 294,000 children in the United States are affected by juvenile arthritis. Juvenile idiopathic arthritis (JIA) is the most common type of arthritis affecting children. Studies show that as many as 1 child in 1,000 develops the condition. What today is known as JIA has gone by other names, including juvenile rheumatoid arthritis (JRA). Today, doctors use the term JIA because it’s considered more accurate. “JRA gave the impression that this is simply rheumatoid arthritis (RA) that happens to occur in childhood,” said Timothy Beukelman, MD, MSCE, Associate Professor of Pediatric Rheumatology at the University of Alabama at Birmingham and pediatric rheumatologist at Children’s Hospital of Alabama. “This is not the case — only around 5% of the kids develop a disease that looks just like RA. The other 95% show a wide range of symptoms that differ from RA.”
Types of Juvenile Idiopathic Arthritis
JIA is an umbrella term encompassing several types of chronic, inflammatory arthritis that develop before the age of 16. “Idiopathic” means that the cause of these conditions isn’t known. Cases of JIA are classified into different types based on children’s symptoms and the number of joints involved. Common types of JIA are the following:
This type affects four or fewer joints in the first six months of symp-toms. It is the most common type of JIA, accounting for up to half of JIA cases. Girls are affected more often than boys. Joint symptoms tend to be milder with oligoarticular JIA than with other types, but children with oligoarticular JIA are more likely to develop an inflammation of the eyes called uveitis. (You can find out more about uveitis here.)
This form of JIA affects five or more joints during the first six months of symptoms. Polyarticular JIA tends to be symmetrical, meaning it occurs in the same joint on both sides of the body. The smaller joints of the hands and feet are commonly affected, and it is not unusual to see polyarticular JIA in the neck and jaw as well. Polyarticular JIA affects an estimated 30% to 40% of children with JIA, and it is more commonly seen in girls.
Also known as Still disease, systemic JIA can affect the entire body. In addition to joint pain, systemic JIA can cause daily fevers and rash. It may also affect the heart, lungs, liver, spleen, and lymph nodes. This type is responsible for roughly 10% of JIA cases and it is seen in roughly equal numbers of girls and boys.
When children have skin symptoms resembling those seen in psoriasis — namely red, scaly patches of skin — the diagnosis is psoriatic arthritis. Juvenile psoriatic arthritis is thought to be similar to psoriatic arthritis seen in adults. Psoriatic arthritis is estimated to account for up to 10% of JIA cases. In some cases, the arthritis comes before the rash; once the rash develops, a child may be “transferred” into this category from one of the others.
This type involves joints and entheses, the areas where tendons or other tissues attach to bone. The back and neck are commonly affected, and children with enthesitis-related JIA can also develop inflammation in the eyes and gastrointestinal tract. Enthesitis-related JIA affects an estimated 10 to 20% of children with JIA, and it is most often seen in boys after age eight.
Some cases of JIA don’t meet the criteria for the categories above, or they may fit into more than one category.
The different types of JIA are strongly believed to be autoimmune conditions. This means that, for reasons unknown, a child’s immune system becomes very active. And instead of going after invading organisms and foreign substances as it is supposed to, the immune system attacks the body’s own tissues. In particular, the immune system attacks the synovium, a thin membrane that lines the insides of joints. The attack causes inflammation, pain, and swelling, and eventually it can lead to damage to the bone and cartilage.
What causes the immune system to go haywire is not yet well understood. There is some research indicating that genetics may play a role, though how large a role isn’t clear. “It seems clear that the answer is not genetic alone and that there is also an environmental piece,” said Dr. Beukelman. “If one identical twin gets JIA, there is less than a 50% chance that the other twin will, too. There must be something more than just [genetics] involved.”
What are the symptoms of juvenile arthritis?
The symptoms that a child experiences vary depending on the specific type of JIA he or she has. The symptoms seen most often include the following:
- Morning stiffness
- Pain, swelling, and tenderness in the joints
- Limping or other changes in walking (younger children may revert to crawling instead of walking)
- Weight loss
- Tiredness and irritability
- Redness or pain in the eyes, blurred vision
Dr. Beukelman stressed that sometimes the arthritis is fairly advanced before the child complains of pain. “Pain may be present but is not required,” said Dr. Beukelman. “Most people think that if there is no pain, it can’t be arthritis, and that is not true. Some kids with arthritis have no pain, at least in the beginning.” In addition, very young children who experience pain may have trouble communicating about it or may not recognize that it is out of the ordinary.
One of the best ways to limit joint damage and other problems in the longer term is to treat the condition early and aggressively. For this reason, it is important to see a doctor as soon as symptoms arise (or are known about by the parent), and to seek a referral to a pediatric rheumatologist if possible.
Reaching a JIA diagnosis
A doctor makes a diagnosis of JIA more by ruling other things out than by finding one sign or symptom that confirms it. To make the diagnosis, the doctor will start by taking a complete medical history. He or she will ask questions such as the following:
- How long do symptoms last?
- At what age did the symptoms start?
- Which joints are affected?
- Are the same joints always affected or do symptoms move from one joint to another?
- What is the child’s pain like?
- Can the child put any weight on the affected body part?
- Has the child’s physical activity level changed?
- Is there any limping, favoring a limb, avoiding play, or crawling rather than walking?
- Is there stiffness when the child first gets up in the morning that improves later in the day?
- How is the child’s general health? Has he or she been ill recently?
- Has there been any recent weight loss or changes in appetite?
- Does anyone else in the family have a history of arthritis?
- Are there other symptoms (such as fever, fatigue, or rash) that occurred before or with joint symptoms?
The doctor may also order x-rays of affected joints. He or she will be checking to make sure there hasn’t been an injury and looking for indications of swelling, narrowing of the spaces between the joints, erosions of the bones, and cysts in the synovium. Unless the arthritis has been present for a long time, however, x-rays usually appear normal.
Although computed tomography (CT) scans are sometimes used, magnetic resonance imaging (MRI) tests are more often used because the doctor can get more information without exposing the child to radiation. An MRI may show thickening of the synovium, the extent of swelling, and inflammation. An ultrasound may also be helpful.
There are no specific laboratory tests for JIA, but tests on blood and urine may be used to rule out other conditions, such as Lyme disease, infection, or cancer. A doctor may also test the blood for substances that signal inflammation, such as rheumatoid factor (RF), C-reactive protein, or antinuclear antibodies. In some children with polyarticular JIA, the blood tests positive for RF, which tells the doctor they have a more aggressive and RA-like form of the condition. However, in many cases of JIA, blood tests are normal.
Common medication for juvenile arthritis
After making a diagnosis, the doctor prescribes medicines with the goal of relieving pain, reducing swelling, and preventing joint damage and complications. Medicines used to treat JIA include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and disease-modifying antirheumatic drugs (DMARDs), often in combination with one another. Which particular drugs a doctor prescribes depends on how many joints are affected, how active the condition is, and how likely the child’s JIA is to lead to joint damage and other complications.
NSAIDs, such as ibuprofen (brand name Advil) and naproxen (Aleve), can help to relieve pain and reduce swelling. However, they do not address the underlying inflammatory process that happens in JIA, so they cannot prevent joint damage.
In some cases, especially in children with oligoarticular JIA or children with one or a few joints that are particularly painful or swollen, the doctor may use a corticosteroid. Corticosteroids are effective at reducing pain and inflammation, but like NSAIDs, they do not affect the disease process. Most of the time, the doctor injects the corticosteroid, usually triamcinolone, directly into the affected joint. In children whose arthritis is more widespread, the doctor may prescribe an oral corticosteroid. However, doctors usually try to avoid using oral corticosteroids in children because they can cause serious side effects such as weakened bones, especially if given for long periods. In addition, corticosteroids can interfere with a child’s growth.
As their name implies, disease-modifying drugs affect the disease process in JIA, interrupting the immune system’s attack on the joints and preventing further damage. The most widely used oral DMARD is methotrexate (Rheumatrex, Trexall). The most common side effects of methotrexate are nausea or abdominal distress, fatigue, mouth sores, and irritation of the liver. Dr. Beukelman noted that children actually tolerate the drug better than most adults, probably because their livers are healthier and much less likely to have been stressed by alcohol use. Still, doctors who prescribe methotrexate conduct regular tests to check for liver damage. In addition, doctors typically prescribe a folic acid supplement to reduce nausea and other side effects.
The most cutting-edge of the DMARDs are a relatively new type called biological response modifiers, or biologics. They directly target specific substances in the immune system that contribute to inflammation. Some are given by injection under the skin, whereas others have to be given through an intravenous infusion. (Currently, the only FDA-approved oral biologic, tofacitinib citrate [Xeljanz], is not approved treat arthritis in children.) Biologics are usually reserved for children whose JIA affects many joints or hasn’t responded well to other medicines.
The biologics typically tried first are those that target an inflammatory protein called tumor necrosis factor (TNF). There are currently two anti-TNF drugs approved by the Food and Drug Administration (FDA) to treat JIA: etanercept (Enbrel) and adalimumab (Humira). Both are self-injected. If the condition doesn’t respond adequately to anti-TNF drugs, the doctor may try the biologic abatacept (Orencia), which targets immune system cells called T cells and is given by infusion. For children with systemic JIA, the doctor may try tocilizumab (Actemra), a biologic that blocks an inflammatory substance called interleukin-6. Actemra was recently approved by the FDA to treat systemic and polyarticular JIA, and it is also given by infusion. Another drug, canakinumab (brand name Ilaris), was recently approved to treat systemic JIA and comes in the form of a monthly injection. (You can read more about the approval here.)
Common side effects of biologic drugs include decreased resistance to infection and redness and swelling at the injection or infusion site. Anti-TNF drugs carry a warning on their labels about reports of cancers in children who use them, but it is possible that these reports do not represent a significant increase in risk. “The problem is that we don’t know if these reports to the FDA actually mean there is an actual increase in cancer cases in children with arthritis receiving this treatment,” said Yukiko Kimura, MD, Chief of Pediatric Rheumatology at The Joseph M. Sanzari Children’s Hospital at Hackensack University Medical Center in New Jersey. “Because we don’t have even basic epidemiological information about the number of children who have these diseases, how many were actually treated with these medications, and how many in each group develop cancers. In fact, one recent study found that children with JIA may have a somewhat increased risk of cancer just by having JIA, and that treatment did not increase the rate of malignancy in these children.”
Because biologics are fairly new — the first one went on the market in the late 1990’s — there is almost no information on what happens to children (or adults) who take these drugs over the long term. To address long-term safety and effectiveness of biologics and other questions about JIA treatments, Dr. Kimura, Dr. Beukelman, and other pediatric rheumatologists have established the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry. CARRA is a research network that involves almost every pediatric rheumatology center in North America, and its members have created a registry to track children with JIA and other pediatric rheumatic diseases such as lupus, dermatomyositis, scleroderma, and vasculitis. Through the registry, researchers can follow children with these diseases to see what medicines they take, how they do on them, and see whether they have any side effects over long periods.
Exercise and physical therapy for JIA treatment
Another important goal of JIA treatment is to increase joint mobility and muscle strength so that children can function well. To achieve this goal, a physical therapist or occupational therapist (or both) may be involved in the care of a child with JIA. These therapists work with children and parents to develop exercise programs to help keep stiffness to a minimum, lessen pain when possible, and maintain range of motion in the affected joints.
Physical therapists assess joint mobility, muscle strength, coordination, and physical fitness. They look at activities that a child can do or wants to do, observe any physical limitations, and then find a way to work around them. Occupational therapists tend to be more involved in hand function. They work with children on reaching, grasping, and moving objects around. There is an emphasis on everyday activities, such dressing, eating, and bathing.
Both types of therapist may fit a child for and train the child to use adaptive equipment, such as splints, which keep joints correctly positioned, stretch muscles that have been shortened because of JIA, and reduce pain. Either a physical or an occupational therapist may design an exercise program for the child to do at home.
What is the prognosis for JIA?
A child’s prognosis depends on the type of JIA he or she has, how early treatment begins, and how well the child follows the treatment plan. How old the child is when symptoms appear seems to matter less. There are no data to show that children are more likely to receive a diagnosis of JIA before or after puberty, and no indicators that the severity of JIA changes in teens.
Although some cases of oligoarticular JIA resolve as the child gets older, this is the exception rather than the rule. “There is a common misconception that children will eventually outgrow JIA,” said Dr. Kimura. “Unfortunately, for most types, the majority [of children] will have arthritis well into adulthood.”
The ultimate goal of treating JIA is to achieve remission, or the long-term subsidence of symptoms. This is most likely to occur with oligoarticular JIA that never affects more than a few joints. In children with the RF-positive form of polyarticular JIA, the condition is more likely to progress to joint destruction and less likely to go into remission. The prognosis for children with polyarticular JIA whose blood is RF-negative is typically better.
The course of systemic JIA varies. A few children with systemic JIA achieve remission, and roughly half have few ongoing symptoms with occasional flares of more severe symptoms. For the rest, the arthritis is persistent, and systemic symptoms such as fever come and go. As with oligoarticular JIA, most children with psoriatic JIA have a better outcome if fewer joints are affected. Enthesitis-related arthritis is variable: Sometimes it goes into remission; other times it can progress into the lower spine.
There are currently no clinical features or laboratory results that can clearly predict outcomes in the early stages of JIA, but many researchers are looking hard for one. “Investigators are trying to find blood or genetic markers that might tell us which patients might do better on which drug, or when it is safe to stop a drug if the patient is doing very well,” noted Dr. Kimura. “That would allow personalization of medicine instead of having to try one medication after another until something works.”
Although both experts interviewed for this article agreed that there is a lot of progress yet to be made in understanding and treating JIA, they noted that they are now able to give children with JIA and their parents a much better prognosis than doctors could even 10 years ago. “It really is an exciting time for anybody with JIA, with so many new treatment options becoming available,” said Dr. Kimura. “We should be encouraged and hopeful that we may even be able to one day find a cure.”
Dr. Beukelman put the recent strides in treatment into even sharper focus. “Twenty years ago, JIA clinics were commonly filled with kids in wheelchairs,” he said. “Now my patients are playing varsity sports, hiking through the woods, and in general doing what kids their age do.”
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