Dr. Greene's Answer
When most people think of arthritis they think of a disease of old people, but Juvenile Rheumatoid Arthritis (JRA) is a group of diseases that strikes the young. In fact, as we have learned more about how this differs from adult rheumatoid arthritis, pediatric rheumatologists have begun calling this Juvenile Idiopathic Arthritis (JIA). JIA is not rare. According to Dr. Sasha Bernatsky of Montreal General Hospital, up to 18 out of every 100,000 children develop JIA each year (Arthritis Care & Research. 57:1, 44-48).
JIA refers to a grab-bag of several distinct arthritis diseases. They can range from relatively mild conditions which disappear at puberty, to relentlessly progressive, crippling arthritis.
The exact cause of the arthritides in JIA remains unknown. The two leading theories are that the diseases are caused by infections with as-yet-unidentified microorganisms, or that the diseases are the result of an over-exuberant auto-immune reaction — one’s own immune system turning against oneself. Either way, some children inherit a genetic predisposition to JIA.
All forms of rheumatoid arthritis are characterized by chronic swelling and inflammation of the synovial membrane which lines joints. If this chronic inflammation continues over years, the joint cartilage and joint bone become eroded and are gradually destroyed. The amount of time the chronic inflammation can last before the damage becomes permanent varies a great deal, but it is a much longer period in Juvenile Idiopathic Arthritis compared to Adult Rheumatoid Arthritis. Many children with JIA outgrow the disease and never develop permanent joint damage, but others may battle the condition for a lifetime.
As stated earlier, there are five major sub-types of rheumatic disease that fall under the name JIA. Note that the names of these disorders and the criteria for diagnosis have changed in recent years, but that many doctors use the Durban Criteria for differentiating the types of JIAs. I imagine the names will continue to change, as we learn more about these conditions.
First, there is polyarticular (many-joint) rheumatoid arthritis. The great majority of children affected by this sub-type of JIA are girls. The polyarticular diseases are characterized by involvement of multiple joints, typically including the small joints of the hands. The polyarticular diseases comprise about 35% of children with JIA. There are two forms of the polyarticular disease differentiated by a blood test for an immune compound called the rheumatoid factor. Rheumatoid Factor Positive Polyarticular Disease tends to appear in late childhood and is the more severe of the two polyarticular diseases. Rheumatoid nodules often appear at the joints. Rheumatoid Factor Negative Polyarticular JIA may begin at any time in childhood and is typically mild. It is rarely associated with rheumatoid nodules at the joint spaces. The affected joints are typically swollen and warm. They tend to be particularly stiff and painful in the morning and following periods of inactivity. Joint involvement in both polyarticular diseases is typically symmetric, with both sides of the body mirroring each other.
The next group of diseases are called pauciarticular (few-joints) diseases. These are characterized by a joint involvement that is limited to four or fewer joints for the first six months of the disease. The large joints are primarily affected, and the arthritis is typically asymmetric. There are subtypes of pauciarticular JIA dependent on whether or not the eye is involved and how the joint involvement spreads over time..
Enthesitis-related arthritis is the third type of JIA, and is characterized by enthesitis inflammation of the areas of connection from bone to tendon or ligament. These children often have back pain, eye involvement (uveitis), or a family history of immune-mediated disorders.
A fourth JIA, psoriatic arthritis, includes children with both arthritis and psoriasis (scaly skin plaques) and those with arthritis along with a family history of psoriasis.
The fifth and final type of JIA is called Systemic JIA. It begins with high, spiking fevers and a fleeting, salmon-colored rash. This accounts for 10 to 20% of children with JRA and affects boys and girls equally. The fever usually spikes once or twice daily, with chills and a rash during the fever spikes. Joint manifestations can be present at the beginning, but may also occur much later. About 25% of children with Systemic JIA will have lifelong arthritis. Children with Systemic JIA are further subdivided based on their age, involved joints, ANA test status, and Rheumatoid factor test status.
Many children with JIA will get better at puberty. Some children will have active arthritis that continues into adulthood. Overall, it seems that those with Rheumatoid Factor Positive Polyarthritis and Systemic JRA have the highest likelihood for ongoing symptoms. About 25 to 50% of the children with Rheumatoid Factor Positive Polyarthritis and Systemic JIA will be affected as adults.
For most children with JIA the overall outlook is good, but in all children this is a chronic disease that will last for several years. The goal of therapy is to provide symptomatic relief, to preserve long-term joint function, and to prevent related complications such as eye involvement.
In general, mild disease is treated with anti-inflammatory medications such as ibuprofen. Intra-articular corticosteroid injection (steroids injected directly to affected joints) may be used. Some children need stronger medications such as methotrexate, cyclosporine, TNF agents, or steroids to control their overactive immune system. Many other strong drugs are being studied as possible treatments for JIA. The specifics of treatment plans depend on the type of JIA and the response to treatment. (Best Practice & Research Clinical Rheumatology. 20: 2, April 2006).
There are many ups and downs ahead for you and your daughter. It will be important to find a caring and knowledgeable physician (usually a pediatric rheumatologist), skilled in the treatment of JIA, to closely monitor your daughter and frequently adjust treatments as necessary. Physical and occupational therapists also play an important role in treating children with JIA.
With most JIA patients there is a difficult and crucial balance to be learned — when to be physically active in spite of pain and when to accept limitations. As a parent it will be important for you to learn to discern when to challenge your daughter physically and when to help her to accept her limitations with grace.