ALL arthritis are not created equal. Most people are familiar with osteoarthritis, which is the arthritis associated with wear and tear of the joints. However, there are other types of arthritis.

In this article we will look at rheumatoid arthritis. This is a chronic disease that occurs when the body’s own immune system attacks synovial tissue, which lines some joints and tendons. The inflamed joint lining or synovium then extends and erodes cartilage and bone, causing joint deformity and progressive physical disability.

The arthritis usually begins in the small joints of the hands and feet, later spreads to the larger joints. The disease also affects other tissues of the body causing pericarditis (inflammation of the lining of the heart), fibrosis of the lungs, soft tissue nodules, nerve injury, and other manifestations.

The cause of rheumatoid arthritis, which occurs two to three times more often in women than men, and most often between the ages of 45 and 65 years, is not known.

Between the insertion of the fibrous capsule and the cartilage, there is a bare area of bone (8) covered by synovium only. This is the area of bone most susceptible to damage when the synovium becomes inflamed.

DIAGNOSIS

The diagnosis of rheumatoid arthritis is made by satisfying four of seven criteria. Criteria one through four must have been present for at least six weeks.

1. Morning stiffness;

2. Arthritis of three or more joint areas;

3. Arthritis of hand joints;

4. Symmetric arthritis;

5. Rheumatoid nodules;

6. Serum rheumatoid ?factor;

7. Radiographic changes.

Since early changes are nonosseous in nature, ultrasound and magnetic resonance imaging are superior to conventional X-rays for detection of disease. For diagnostic purposes, symptomatic joints and joints typically involved in rheumatoid arthritis (wrist and hand joints) should be imaged.

Early features of rheumatoid arthritis are inflammatory. They include hyperemia, synovitis and joint effusions.

Alterations in the microcirculation cause the bone near joints to become less dense. This change may not be seen on X-ray for weeks.

As the destructive process continues, bone erosions occur. The formation of scar tissue and fibrosis leads to concentric joint narrowing. As the disease progresses, the inflammatory process may lead to massive erosions and bone mutilation, as well as destruction of the soft tissue structures of and around the joint. Scar formation, fibrosis, subluxation or complete dislocation, and finally fibrous and bony fusion are late features of the disease.

MANAGING RHEUMATOID ARTHRITIS

The hallmark of rheumatoid arthritis is bilateral symmetric arthritis of more than three joints. As the disease progresses, large extremity joints and joints of the vertebral spine may be affected.

Early institution of combination therapy manages the disease. Disease-modifying antirheumatic drugs, non-steroidal anti-inflammatory drugs (NSAIDS) and corticosteroids all play a role.

Physiotherapy is also important to preserve mobility of the joints.

Dr Duane Chambers is a consultant radiologist and founding partner of Imaging and Intervention Associates located at shops 58 and 59 Kingston Mall, 8 Ocean Boulevard. He may be contacted through the office numbers 618-4346 or 967-7748.