Juvenile arthritis (JA), which occurs in children under 16 years of age, can include a myriad of symptoms and physiological problems. The causes of JA are not completely understood, but a combination of genetics and environmental factors appears to play a part in the formation of the disease.
JA is an umbrella term that comprises several specific classes of childhood arthritis. Systemic-onset JA is one. It affects only about 10 percent of JA patients, but it tends to have the most severe symptoms and be associated with other diseases.
Children are typically diagnosed with systemic-onset JA by the age of 5, but commonly begin showing symptoms around age 2. Unlike most forms of JA, which are considered autoimmune diseases, systemic-onset JA is typically identified as an autoinflammatory disorder.
How does systemic-onset juvenile arthritis affect the body?
The first indicators of systemic-onset JA are typically a recurring fever that reaches 102-103°F once or twice daily and a flat, pink rash that may move between the trunk, arms, or legs. These symptoms tend to spike once a day, so both are most intense for the same few hours each day.
Arthritis symptoms usually begin to develop slowly after the fever and rash appear, and continue to worsen over weeks and months. Stiffness, pain, and swelling sometimes affect only a single joint, but more often involve a combination of joints, including the knees, wrists, and ankles. Uneven and slowed growth of arms and legs can also occur. Although this can be caused by the disease itself, it can also be the consequence of corticosteroid treatments.
Systemic inflammation also typically causes enlarged lymph nodes and swelling of internal organs such as the liver, spleen, heart, or lungs. Systemic symptoms and the fever and rash may resolve over time, leaving only symptoms of arthritis. The changes in the way the disease presents itself can make it difficult to diagnose.
The severity of the symptoms usually varies from one patient to another. Some children may have such severe systemic complications that they need to stay in a hospital to manage the disease. Others may be able to cope with the cycling fever, rashes, and joint pain from home. Early diagnosis and treatment are the primary factors in improving outcome.
How is systemic-onset juvenile arthritis diagnosed?
Physicians will typically base a diagnosis of systemic-onset JA on a patient’s medical history, a physical examination, X-ray images of joints, and the results of several blood tests. No single laboratory test can identify the disease, but laboratory results of children with systemic-onset JA typically display a combination of anemia, high white blood cell counts, increased platelet production, and blood indicators of increased inflammation.
How is systemic-onset JA treated?
Traditional treatment of systemic-onset JA begins with nonsteroidal anti-inflammatory drugs (NSAIDs). If these do not relieve the symptoms, treatment may be modified to include corticosteroids. Corticosteroids can carry a number of side effects such as growth delay and severe osteoporosis. So new biologic therapies are becoming more prevalent in the treatment of systemic-onset JA.
The majority of biologics used to treat the disease aim to inhibit interleukin 1 and interleukin 6, inflammatory proteins that are overactive in children with systemic-onset JA. Because biologics have fewer side effects, some physicians are forgoing traditional steroid treatment and prescribing biologic therapies directly after diagnosis.
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