An accurate diagnosis of juvenile rheumatoid arthritis (JRA) is very important as the symptoms of this disease such as joint swelling, stiffness and pain may resemble other disorders such as viral or bacterial infections, inflammatory bowel diseases, systemic lupus erythematosus and Lyme disease. When these symptoms appear, it is suggested to consult a pediatric rheumatologist for correct diagnosis of the disease. The diagnosis is made on the basis of symptoms, physical examination and medical history.
The 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 checked and this 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 of juvenile rheumatoid arthritis.
Since there is no particular lab test that confirms the evidences of JRA, this disease is diagnosed on the basis of medical history, physical examination and results of lab tests and imaging tests. Some of frequently prescribed lab tests are erythrocyte sedimentation rate, complete blood tests, determination of antinuclear antibody and rheumatoid factor. Although erythrocyte sedimentation rate (ESR) is a nonspecific marker, it is an indicative of active inflammation in the body. Generally, it may be raised in polyarticular JRA, while normal in the pauciarticular disease.
The complete blood count (CBC) test is done 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. A positive ANA result can be observed in the children having pauciarticular JRA, but uncommon in systemic JRA. Positive ANA is associated with 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. It is a group of autoantibodies which are present in some people having rheumatoid arthritis and juvenile rheumatoid arthritis. It is most commonly positive in polyarticular JRA, while rarely positive in systemic JRA.
In addition to these lab tests, there are some imaging tests such as x-ray, bone scan, MRI and CT scan and dual-energy x-ray absorptionmetry which are helpful the diagnosis of juvenile rheumatoid arthritis. X-ray, MRI and CT scan may help to detect the damage in the affected joints. Bone scan is another beneficial imaging test which can detect the inflammation of joints and bone as well as other abnormalities. Besides these tests, some other investigations suggested for the diagnosis of JRA are arthrocentesis and synovial biopsy.
