Diagnosing rheumatoid arthritis
By means of a detailed physical examination and a thorough discussion with the individual about their symptoms, as well as their personal and family medical history, a doctor may suspect the problem to be rheumatoid arthritis (RA).
If this is the case, a series of diagnostic tests will be done, including laboratory tests as well as X-rays.
These tests can show whether you’re anaemic, which 80% of people with RA are. High levels of inflammation may also show up in your blood tests.
Two markers of inflammation, the erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP), are increased in many people with active disease. These are useful when raised as they can be used to monitor progress.
Rheumatoid factor (RF) is an antibody found in some people with RA, but it can also point to other inflammatory diseases, especially in older people, so its presence is not conclusive. Someone with RA can also test negative to RF.
Another antibody test, anti-CCP (anti-cyclic citrullinated peptide) antibodies, has been shown to be more specific and useful in the diagnosis of early rheumatoid arthritis. Sixty to 70% of people with RA test positive for anti-CCP antibodies. These antibodies are also useful to predict the likely course of RA as well as the response to therapy.
X-rays and other imaging tests
These tests aren’t always useful early in the disease, revealing mainly swelling of the soft tissues around the joint and fluid in the joint space. There may as yet not be any damage to the joints. The early appearance of bone erosion in the joints could point to an aggressive disease process, and aggressive treatment could be indicated. X-rays are useful in monitoring progress as they provide independent information on your response to a particular therapy.
Magnetic resonance imaging (MRI) and ultrasound scanning can be more effective in picking up any changes in the joints early. They’re also useful for assessing the effectiveness of treatment of the disease.
Course and prognosis
With the correct approach of remaining active and keeping a check on your weight, osteoarthritis need not become a disabling condition. However, the damage to the joints usually starts before symptoms arise, making it difficult to act early.
Reviewed by Dr Stella Botha, rheumatologist at Groote Schuur Hospital, Cape Town (MBChB, MRCP, PhD). November 2017
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