Diagnosing Juvenile Arthritis

Early diagnosis and treatment can control inflammation, relieve pain, prevent joint damage, and maintain a child's ability to function. Your doctor will order a wide range of tests. A complete medical history and physical examination, blood tests, and x-rays will help your doctor rule out other conditions that cause arthritis. Doctors usually suspect JA, along with several other possible conditions, when they see children with persistent joint pain or swelling, unexplained skin rashes, and fever associated with swelling of lymph nodes or inflammation of internal organs.

Because a child may have no symptoms of juvenile arthritis, and because some of the symptoms can be associated with other diseases, a diagnosis may be difficult. Because there is no actual test for juvenile arthritis, the diagnosis is made by excluding other conditions that may cause similar symptoms, such as bone disorders or breaks, fibromyalgia, infection, Lyme disease, lupus, or cancer.

When diagnosing JA, a doctor must consider not only the symptoms a child has but also the length of time these symptoms have been present. Joint swelling or other objective changes in the joint with arthritis must be present continuously for at least 6 weeks for the doctor to establish a diagnosis of JA. Because this factor is so important, it may be useful to keep a record of the symptoms and changes in the joints, noting when they first appeared and when they are worse or better.

The doctor is likely to begin by taking a complete medical history and performing a complete medical exam. Because there are many causes of joint pain and swelling, the doctor must rule out other conditions before diagnosing JA. These include physical injury, bacterial or viral infection, Lyme disease, inflammatory bowel disease, lupus, dermatomyositis, and some forms of cancer. The doctor may use additional laboratory tests to help rule out these and other possible conditions.

Tests include:

  • lab tests on blood or urine
  • X-rays (o rule out breaks or damage to bones )
  • imaging tests, such as an MRI
  • blood culture to check for bacteria
  • tests for viruses
  • tests for Lyme disease
  • bone marrow exam, which is used to check for leukemia
  • test for rheumatoid factor
  • bone scan to detect changes in bones and joints
  • joint fluid sampling and synovial tissue sampling, which might be performed by an orthopedic surgeon

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