Juvenile rheumatoid arthritis (JRA) is a childhood disease that affects the joints. There are several different types of JRA, but systemic-onset juvenile rheumatoid arthritis is the rarest form, accounting for just 10%-20% of all JRA cases.
Systemic-onset JRA causes high, spiking fevers, rash, and joint aches. The word "systemic" means that it affects the entire body. Systemic-onset JRA usually begins when a child is between 5 and 10 years old, and it affects boys and girls equally.
Systemic-onset JRA is also known as Still's disease, named after the English doctor Sir George F. Still, who first recognized the illness in children in the late 1800s.
No one really knows what causes systemic-onset JRA. It is believed to be caused by a faulty immune response. That response may be triggered by another factor, such as stress, or a viral or bacterial infection.
Symptoms of Systemic-Onset JRA
The hallmark signs of systemic-onset JRA are a very high fevers (102 degrees Fahrenheit or higher) and a pale pink or salmon-colored rash, usually on the child's chest and thighs. Because of these symptoms, systemic-onset JRA is sometimes confused with a bacterial infection, but systemic-onset JRA does not respond to antibiotic treatment.
The fever from systemic-onset JRA tends to spike several times during the day, usually peaking at night and then improving in the morning. Children also have joint pain and/or swelling, which can become more painful when the fever peaks.
Symptoms come and go over days, weeks, or months. When the fever is low, the child will seem to be fine, but when the fever returns the child will look and act sick. Children can have "good" days with few or no symptoms, and "bad" days with flare-ups of more severe symptoms.
Systemic-onset JRA also can cause inflammation of the lining of the lung (pleuritis) or lining of the heart (pericarditis), swollen lymph nodes, and an enlarged spleen and liver. Children with the condition may grow more slowly than normal.
Diagnosing Systemic-Onset JRA
There is no single test for systemic-onset JRA. Doctors diagnose the disease by doing a physical examination and looking for its characteristic symptoms. Tests help rule out other diseases with similar symptoms (including bacterial or viral infections, and other forms of arthritis).
The following tests may be performed:
- Blood, urine, and joint fluid tests
- X-rays, MRIs, and other imaging tests
Tests may reveal:
- Low red blood cell count (anemia)
- High white blood cell count
- High platelets (the cells in blood that help it clot)
- Elevated levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), blood markers of inflammation
How Is Systemic-Onset JRA Treated?
Doctors typically treat the condition with medications such as:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) such as celecoxib (Celebrex), diclofenac (Voltaren), ibuprofen (Advil, Motrin), and naproxen (Aleve, Naprosyn); these drugs help relieve fever, pain, and joint inflammation.
- Corticosteroid medications such as prednisone; these drugs suppress the immune response and relieve inflammation.
- Many of the medications used for adult RA have been tried but recent advances suggest that some biologic agents may have greater effectiveness, such as Kineret or tocilizumab (Actemra). Additional studies will need to be done to determine what the best treatment is
It is important for children with systemic-onset JRA to get plenty of rest, especially when they are experiencing symptoms. When children are feeling up to it, exercise can help keep their joints strong and mobile. Physical therapy also may be helpful.
In many children with systemic-onset JRA, the fever and rash go away within a few months. How quickly the condition improves depends on its severity. In some people, the arthritis can last much longer, even into adulthood. It can flare up later in life. The disease is rarely life threatening.