Differentiate between osteoarthritis and rheumatoid arthritis. How does the pathophysiology of the diseases differ?

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two different types of arthritis. OA is a degenerative joint disease that is caused by wear and tear on the joints due to overuse or aging, while RA is an autoimmune disorder in which the body’s immune system mistakenly attacks its own joint tissues.

The pathophysiology of these two diseases differs in that OA affects only certain parts of the joint, such as the cartilage, while RA affects multiple areas including synovial membrane, tendons, ligaments and even bone tissue. Additionally, OA results in gradual deterioration of joints over time while RA can cause inflammation leading to pain and swelling within a matter of days or weeks. Furthermore, OA does not cause systemic symptoms such as fatigue or fever whereas RA may be associated with extra-articular manifestations such as rash, eye irritation or mouth sores.