For the diagnosis of juvenile rheumatoid arthritis, there are various options such as physical examination, laboratory tests, imaging tests and joint fluid analysis. A pediatric rheumatologist gets the detailed information about the child’s symptoms, accidents, injuries, medication, allergies, vaccinations and family’s lifestyle and habits. In the physical examination, movement and flexibility of the joints and muscles are examined. The physical examination covers all the systems especially skin, eyes, digestive system and heart which may be affected by JRA. After complete physical examination, some lab tests are suggested to confirm the diagnosis.
Some of commonly prescribed lab investigations are erythrocyte sedimentation rate (ESR), complete blood count (CBC), determination of antinuclear antibody (ANA) and rheumatoid factor (RF). Although erythrocyte sedimentation rate (ESR) is a nonspecific marker, it indicates an active inflammation in the body. Generally, it may be raised in polyarticular JRA, while normal in the pauciarticular disease.
Complete blood count (CBC) is a common test used to determine the basic cellular components of blood such as white blood cells, red blood cells and platelets. This test is performed to detect the anemia which is common in the children with JRA. This test also indicates various abnormalities in white blood cells or platelets which are associated with the immune system and blood clotting. The counts of white blood cells and platelets are found to be normal in the children with JRA.
Antinuclear antibody (ANA) is one of the antibodies that may be produced in some autoimmune diseases such as juvenile rheumatoid arthritis. The children having pauciarticular JRA have positive ANA results, but it is uncommon in systemic JRA. Positive ANA is associated with a greater risk of eye involvement (uveitis).
Determination of rheumatoid factor (RF) is one of important tests for the diagnosis of juvenile rheumatoid arthritis as well as to determine the type of JRA. It 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. Actually, positive RF result is considered as a sign of JRA progressing to adult-type rheumatoid arthritis.
Besides these lab tests, some imaging tests such as x-ray, bone scan, MRI and CT scan and dual-energy x-ray absorptionmetry are helpful for the diagnosis of juvenile rheumatoid arthritis.
