Which of the following is difference between Rheumatoid arthritis and osteoarthritis –
**Core Concept**
Rheumatoid arthritis (RA) and osteoarthritis (OA) are two distinct types of arthritis with different pathophysiologies and clinical manifestations. RA is an autoimmune disease characterized by inflammation and destruction of joints, whereas OA is a degenerative joint disease resulting from wear and tear of cartilage.
**Why the Correct Answer is Right**
The key difference between RA and OA lies in their underlying mechanisms. RA is mediated by autoantibodies against the Fc region of IgG, leading to the formation of immune complexes and activation of immune cells, which cause inflammation and joint destruction. In contrast, OA is primarily due to mechanical stress and enzymatic degradation of cartilage, resulting in the loss of joint space and formation of osteophytes. The synovial lining in RA is hyperplastic and produces pro-inflammatory cytokines, whereas in OA, the synovium is hypertrophic but non-inflammatory.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because both RA and OA can cause joint pain and stiffness, making it a nonspecific characteristic.
**Option B:** This option is incorrect because both conditions can exhibit radiographic joint space narrowing, which is a common feature of both diseases.
**Option C:** This option is incorrect because both RA and OA can cause joint deformities, such as subluxation or contracture, due to chronic inflammation or mechanical stress.
**Clinical Pearl / High-Yield Fact**
Remember that the presence of systemic symptoms, such as fever, weight loss, and fatigue, in a patient with joint pain suggests RA, whereas OA typically presents with localized joint pain and stiffness.
**Correct Answer:** D.