What characterizes rheumatoid arthritis?

Rheumatoid arthritis (RA) is characterized primarily by chronic inflammation of the joint synovium. This autoimmune condition leads to the immune system mistakenly attacking the synovial tissue, resulting in persistent inflammation. This chronic inflammatory process can lead to joint damage, and if untreated, may result in structural deformities. The synovium becomes thickened, and the buildup of inflammatory cells can lead to the accumulation of synovial fluid and the formation of pannus, which erodes bone and cartilage.

The other options do not accurately describe rheumatoid arthritis. A sudden onset of joint pain is more characteristic of other types of arthritis, such as gout or septic arthritis. The presence of bone spurs (osteophytes) is typically associated with osteoarthritis, not rheumatoid arthritis. While weakness in surrounding muscles can occur due to disuse or pain, it is not a defining characteristic of RA itself. Therefore, the hallmark of rheumatoid arthritis clearly points to the chronic inflammation of the joint synovium as the defining feature of the disease.