Which of the following is a type of seronegative spondyloahropathy ?
**Core Concept**
Spondyloarthritis is a group of inflammatory rheumatic diseases characterized by axial or peripheral joint involvement, often accompanied by extra-articular manifestations. Seronegative spondyloarthritis refers to a subset of these conditions where rheumatoid factor (RF) is negative.
**Why the Correct Answer is Right**
Psoriatic arthritis (PsA) is a type of seronegative spondyloarthritis that primarily affects patients with psoriasis. It is characterized by inflammation of the joints and entheses (sites where tendons or ligaments attach to bone), leading to pain, stiffness, and swelling. PsA is associated with the presence of HLA-B27 and can cause significant joint damage and disability if left untreated. The pathophysiology of PsA involves an imbalance of pro-inflammatory cytokines, such as TNF-alpha and IL-17, which contribute to joint inflammation and destruction.
**Why Each Wrong Option is Incorrect**
**Option A:** Ankylosing spondylitis (AS) is a type of spondyloarthritis, but it is typically not considered seronegative. AS is characterized by chronic inflammation of the spine and sacroiliac joints, leading to eventual fusion of these joints.
**Option B:** Reactive arthritis (ReA) is a type of spondyloarthritis, but it is typically associated with a history of gastrointestinal or genitourinary infection. ReA is characterized by asymmetric oligoarthritis and enthesitis.
**Option C:** Enteropathic arthritis is a type of spondyloarthritis associated with inflammatory bowel disease (IBD), such as Crohn's disease or ulcerative colitis. It is typically not considered seronegative.
**Clinical Pearl / High-Yield Fact**
Psoriatic arthritis is a classic example of a seronegative spondyloarthritis, and its diagnosis requires a thorough evaluation of the patient's skin and joint symptoms. A high index of suspicion is necessary to diagnose PsA, as its symptoms can be subtle and easily missed.
**Correct Answer:** C.