A 2007 study by the Centers for Disease Control and Prevention estimates that 294,000 children in the United States have been diagnosed with some form of arthritis or inflammation of the joints. Juvenile rheumatoid arthritis, the most common form of pediatric arthritis, is divided into three types: systemic, polyarticular and pauciarticular. The cause is unknown but may be related to the immune system attacking and destroying healthy tissue. Signs and symptoms may vary from day to day.
The most common symptoms of JRA are related to the joints: inflammation, contracture, damage and change in growth. Joint stiffness on awaking, joint pain, limited range of motion, muscle weakness and back pain are common, according to the University of Maryland Medical Center. Joints may be warm, swollen or red. A child may limp, seem more clumsy or stop using an affected limb. The number of joints involved defines two types of JRA. Polyarticular JRA involves five or more joints, often on both sides of the body, including the joints of the extremities, jaw, fingers, hands and neck. Pauciarticular JRA involves four or fewer joints, usually the hip, knee, elbow or ankle, and often on only one side of the body, according to the Arthritis Foundation.
Children with systemic JRA, the least common type, have fevers and rashes in addition to joint swelling or pain. The fevers are usually high, up to 103 degrees, and the rashes involve the trunk and extremities, according to the University of Maryland Medical Center. Some children with polyarticular arthritis also have systemic symptoms, according to the Arthritis Foundation, including low grade fevers and anemia--low red blood cell count.
Children with pauciarticular JRA may complain of red eyes, eye pain, photophobia—pain when looking at light—and vision changes, according to the University of Maryland Medical Center. Patients may also have inflammation of the eyes, called uveitis.
Systemic JRA, formerly known as Still’s disease, causes inflammation and enlargement of the liver, spleen and lymph nodes. In some cases, reports the Arthritis Foundation, the lining of the heart or lungs may become inflamed as well. Less often, children with polyarticular JRA may have organ involvement.
Diagnosis usually depends on a medical history and physical examination. Although there is no single diagnostic test available for juvenile rheumatoid arthritis, X-rays are used to detect damage to the joints and blood tests can assist in ruling out other diseases.