Systemic juvenile idiopathic arthritis
What is JIA?
Juvenile idiopathic arthritis (JIA) also known as juvenile rheumatoid arthritis is a childhood disease that affects the joints. There are several different types of JIA, including systemic JIA
Systemic JIA causes high, spiking fevers, rash and joint aches. The word ‘systemic’ means that it affects the entire body. Systemic JIA usually begins when a child is between five and 10 years old, and it affects boys and girls equally.
Systemic JIA is also known as Still's disease, named after the English doctor Sir George F Still, who first recognised the illness in children in the late 1800s.
No-one really knows what causes systemic JIA. It is believed to be caused by a faulty immune response. That response may be triggered by another factor such as stress or by a viral or bacterial infection.
Symptoms of systemic JIA
The typical signs of systemic JIA are very high fevers (38.8C/102F or higher) and a pale pink or salmon-coloured rash, usually on the child's chest and thighs. Because of these symptoms, systemic JIA is sometimes confused with a bacterial infection, but systemic JIA does not respond to antibiotic treatment.
The fever from systemic JIA 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 JIA can also 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 JIA
There is no single test for systemic JIA. Doctors diagnose the disease by doing a physical examination and looking for its characteristic signs. 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 or anaemia
- 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. These drugs help relieve fever, pain and joint inflammation.
- Corticosteroid medications such as prednisolone, which suppress the immune response and relieve inflammation.
- Disease-modifying antirheumatic drugs (DMARDs) such as methotrexate, sulfasalazine and hydroxychloroquine - these drugs slow the progression of the disease.
- Biologic drugs (which are also in the category of DMARDs) such as etanercept, infliximab and adalimumab.
It is important for children with systemic JIA 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. Physiotherapy also may be helpful.
In many children with systemic JIA, 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.