Which statement best differentiates rheumatoid arthritis from osteoarthritis?

• A. RA typically presents with morning stiffness and symmetric small-joint involvement; OA presents mechanical pain with asymmetry.
• B. RA is typically seronegative for RF and anti-CCP.
• C. RA shows osteophytes on imaging while OA shows erosions.
• D. OA always involves systemic symptoms such as fever.

Answer: (A)

This item tests the pattern that separates inflammatory arthritis from degenerative arthritis by how symptoms present in the joints. In rheumatoid arthritis, the inflammation tends to hit small joints in a symmetrical way, often with morning stiffness that is prolonged. That combination of stiffness after rest and a symmetric pattern—especially in the hands and wrists—reflects synovial inflammation that characterizes RA.

Osteoarthritis, on the other hand, is a degenerative, mechanical type of pain. It usually worsens with use and improves with rest, and the joint involvement is often asymmetrical, affecting load-bearing joints and the thumb base with bony enlargements rather than a primary inflammatory process.

So the statement that best differentiates RA from OA is the one describing morning stiffness and symmetric small-joint involvement for RA, versus mechanical pain with asymmetry for OA.

Other choices mischaracterize RA or OA: RA commonly has seropositivity for RF and anti-CCP antibodies, so a claim that it’s typically seronegative isn’t accurate; imaging features differ—OA shows osteophytes with joint space narrowing, while RA tends to produce erosions from inflammatory synovitis; and OA does not inherently involve systemic symptoms like fever.