The presence of Swan neck deformities indicates which type of arthritis?

Swan neck deformities are a classic clinical manifestation associated with rheumatoid arthritis, a chronic inflammatory autoimmune disorder. This condition leads to the destruction of joint synovium, resulting in changes to the ligaments and tendons surrounding the joints.

The deformity itself is characterized by hyperextension of the proximal interphalangeal (PIP) joints combined with flexion of the distal interphalangeal (DIP) joints, affecting the fingers. This specific positioning occurs due to the imbalance of forces in the hand, which is a result of inflammatory processes initiated by rheumatoid arthritis.

While other forms of arthritis may present with distinct alterations in joint structure, they do not typically lead to the signature Swan neck deformity. For instance, gout is characterized by acute attacks of arthritis, often affecting the big toe and involving tophi formation, while osteoarthritis typically results in joint space narrowing, bone spurs, and diminished cartilage without producing the same deformity. Psoriatic arthritis presents with a variety of patterns, but Swan neck deformities are not a hallmark of the disease.

Thus, the presence of Swan neck deformities is strongly indicative of rheumatoid arthritis, emphasizing the specific pathophysiological changes that occur in this condition.