Extra-aicular manifestations of RA –
**Core Concept**
Rheumatoid Arthritis (RA) is a chronic autoimmune disorder characterized by inflammation of the synovium, leading to joint damage and deformity. However, RA also has extra-articular manifestations, which are complications that occur outside the joints, affecting various organs and systems.
**Why the Correct Answer is Right**
Extra-articular manifestations of RA are a result of the systemic nature of the disease. The immune complexes and inflammatory mediators released in RA can affect multiple organs, including the skin, lungs, heart, and eyes. For example, the formation of rheumatoid nodules in the skin is a common extra-articular manifestation of RA. These nodules are composed of granulomatous tissue and are thought to result from the deposition of immune complexes in the skin.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because while RA can cause eye inflammation (scleritis), it is not the most common extra-articular manifestation of RA.
* **Option B:** This option is incorrect because while RA can cause lung disease (interstitial lung disease), it is not the most common extra-articular manifestation of RA.
* **Option C:** This option is incorrect because while RA can cause cardiac disease (pericarditis), it is not the most common extra-articular manifestation of RA.
**Clinical Pearl / High-Yield Fact**
Rheumatoid nodules are a classic extra-articular manifestation of RA and are often seen on the extensor surfaces of the elbows and hands. They are a result of the deposition of immune complexes in the skin and are a key diagnostic feature of RA.
**Correct Answer: C. Cardiovascular manifestations.**