Rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disorder that causes the immune system to attack the joints. It is a disabling and painful inflammatory condition, which can lead to substantial loss of mobility due to pain and joint destruction. The disease is also systemic in that it often also affects many extra-articular tissues throughout the body including the skin, blood vessels, heart, lungs, and muscles.

Diagnosis

The American College of Rheumatology has defined (1987) the following criteria for the diagnosis of rheumatoid arthritis http://www.rheumatology.org/publications/classification/ra/ra.asp?aud=mem:

Related Topics:
American College of Rheumatology - 1987

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• Morning stiffness of >1 hour.
• Arthritis and soft-tissue swelling of >3 of 14 joints/joint groups
• Arthritis of hand joints
• Symmetric arthritis
• Subcutaneous nodules in specific places
• Rheumatoid factor at a level above the 95th percentile
• Radiological changes suggestive of joint erosion

At least four criteria have to be met to establish the diagnosis, although many patients are treated despite not meeting the criteria.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

When RA is being clinically suspected, immunological studies are required, such as rheumatoid factorhttp://www.labtestsonline.org/understanding/analytes/rheumatoid/test.html (RF, a specific antibody). A negative RF does not rule out RA; rather, the arthritis is called seronegative. During the first year of illness, rheumatoid factor is frequently negative. 80% patients eventually convert to seropositive status. RF is also seen in other illnesses, like Sjögren's syndrome, and in approximately 10% of the healthy population, therefore the test is not very specific. Because of this low specificity, a new serological test has been developed in recent years, which tests for the presence of so called anti-citrullinated protein (ACP) antibodies. Like RF, this test can detect approximately 80% of all RA patients, but is rarely positive in non-RA patients, giving it a specificity of around 98%. In addition, ACP antibodies can be often detected in early stages of the disease, or even before disease onset. Currently, most common test for ACP antibodies is the anti-CCPhttp://www.labtestsonline.org/understanding/analytes/ccp/test.html (cyclic citrulinated peptide) test. Also, several other blood tests are usually done to allow for other causes of arthritis, such as lupus erythematosus. The erythrocyte sedimentation rate (ESR), C-reactive proteinhttp://www.labtestsonline.org/understanding/analytes/crp/test.html, full blood count, renal function, liver enzymes and immunological tests (e.g. antinuclear antibody/ANA)http://www.labtestsonline.org/understanding/analytes/ana/test.html are all performed at this stage. Ferritin can reveal hemochromatosis, which can mimic RA.

Related Topics:
Immunological - Rheumatoid factor - Antibody - Sjögren's syndrome - Blood test - Lupus erythematosus - Erythrocyte sedimentation rate - C-reactive protein - Full blood count - Renal function - Liver enzyme - Antinuclear antibody - Ferritin - Hemochromatosis

~ ~ ~ ~ ~ ~ ~ ~ ~ ~