Clinical diagnosis of rheumatoid arthritis.

Rheumatoid arthritis is a common disease that is now known to progress to irreversible erosive changes in the joints much more quickly than previously recognized. Physicians thus need to identify the early symptoms and signs to make a prompt clinical diagnosis and then start earlier aggressive treatment. Critical features are morning stiffness and symmetrical inflammation involving usually small joints of the hands and feet. Soft tissue swelling is the most important sign of inflammation and begins most often at the metacarpal phalangeal or proximal interphalangeal joints. Joints are tender and warm but often not hot and red. Elevation of erythrocyte sedimentation rate can help confirm the presence of inflammation but the most important laboratory test is synovial fluid analysis which further confirms inflammation but can also help exclude many of the other potentially confusing causes of arthritis. Rheumatoid factor is present in 75% of patients but can also be seen with some other diseases.