Which autoimmune arthritis typically starts in small joints and can cause joint deformities?

• A. Osteoarthritis
• B. Rheumatoid Arthritis
• C. Gout
• D. Psoriatic Arthritis

Answer: (B)

Autoimmune inflammatory arthritis that begins in the small joints of the hands and can progress to deformities is most consistent with rheumatoid arthritis. This condition involves the body’s immune system attacking the synovial lining, causing symmetric swelling of small joints such as the metacarpophalangeal and proximal interphalangeal joints. Over time, chronic inflammation leads to pannus formation, cartilage and bone erosion, and ligament laxity, producing noticeable deformities like ulnar deviation, swan neck, and boutonnière changes.

Osteoarthritis is a degenerative process, typically affecting larger weight-bearing joints and lacking the autoimmune, symmetric pattern and early deformities seen in rheumatoid arthritis. Gout presents with acute, often single-joint inflammation due to urate crystals and does not characteristically start in small joints with progressive deformities. Psoriatic arthritis can involve small joints and cause deformities too, but it is associated with psoriasis and has patterns that can include distal joint changes and dactylitis, not the classic symmetric small-joint erosion seen in RA.

So the described pattern fits rheumatoid arthritis best.