Juvenile rheumatoid arthritis is a form of arthritis that usually affects the children below the age of 17. It is characterized by inflammation and tenderness of the muscles, tendons, bones, joints and nerves. However, it can also affect other organs of the body like the heart, eyes, liver and lungs. In some cases, this form of juvenile arthritis is known to cause serious joint damage and stunted growth. Hence, early diagnosis of juvenile rheumatoid arthritis is very important to manage the symptoms and prevent joint damage.
When the symptoms of JRA appear, it is suggested to consult a pediatric rheumatologist for correct diagnosis of juvenile rheumatoid arthritis. Symptoms, physical examination and medical history of the patient are important factors in the diagnosis. You should inform about child’s symptoms, accidents, injuries, medication, allergies, vaccinations and family’s lifestyle and habits to the pediatric rheumatologist. In the physical examination, mobility and flexibility of the joints and muscles are examined. Physical examination also covers all the systems especially skin, eyes, digestive system and heart which may suspect to be involved in JRA.
After the physical examination, some lab tests are suggested for the confirmation of diagnosis of juvenile rheumatoid arthritis. Some of frequently prescribed lab tests are erythrocyte sedimentation rate, complete blood tests, determination of antinuclear antibody and rheumatoid factor. Erythrocyte sedimentation rate (ESR) may indicate an active inflammation in the body. Generally, it may be raised in polyarticular JRA, while normal in the pauciarticular disease. In addition to this, complete blood count (CBC) test is done to detect the anemia which is common in the children with JRA.
Antinuclear antibody (ANA) is one of the antibodies that may be produced in some autoimmune diseases like juvenile rheumatoid arthritis. Children with pauciarticular JRA can give a positive ANA result, but uncommon in systemic JRA. Positive ANA test indicates a greater risk of eye involvement (uveitis).
A determination of rheumatoid factor is one of significant tests for the diagnosis of juvenile rheumatoid arthritis as well as to determine the type of JRA. Rheumatoid factor is a group of autoantibodies present in some people having rheumatoid arthritis and juvenile rheumatoid arthritis. It is most frequently positive in polyarticular JRA, while rarely positive in systemic JRA.
Besides these laboratory investigations, some imaging tests like as x-ray, bone scan, MRI and CT scan and dual-energy x-ray absorptionmetry are important for the diagnosis of JRA. Radiography of affected joint is important to rule out other diseases including septic arthritis or osteomyelitis. Besides this, bone scanning is a significant test to identify a potential focus of osteomyelitis or other abnormalities.
Magnetic resonance imaging (MRI) scan of the affected joint is performed with gadolinium injection which enhances inflamed synovial. It is helpful to detect the joint deformity and damage. Besides this, computerized tomography (CT) scan is performed to detect osteoid osteoma in a child with fewer pain and unpredictable findings in physical examination. In addition to these scans, echocardiography is performed to detect possible systemic JRA accompanied by fever.
Along with these tests, dual-energy radiograph absorptiometry (DXA) is performed to detect osteopenia in children with polyarticular JRA. Besides that, synovial biopsy is performed to determine synovial infiltration with mature T and B lymphocytes and plasma cells.
