26th January 2024

Rheumatoid arthritis (RA) 

A number of features can be used to distinguish between RA and OA, especially the number and distribution of affected joints. RA tends to cause a symmetrical small-joint polyarthritis. The joints most commonly affected are the metacarpophalangeal (MCP) joints in the hands, with sparing of the distal interphalangeal joints (DIPS). Patients with RA generally experience morning stiffness for longer than 30 minutes, which can be relieved with activity and can often present with systemic symptoms such as fever and fatigue. In terms of investigations, CRP and ESR are raised in RA, rheumatoid factor and anti-CCP are positive, and characteristic features can be seen on imaging, such as loss of joint space, erosions, soft tissue swelling and soft bones (osteopenia). Nevertheless, it can be difficult to distinguish between OA and inflammatory arthropathies, and the two conditions can often co-exist.