This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rheumatoid Arthritis, Subject name: Orthopaedics
[{'content': 'A 35 year old female presented with MCP and PIP pain. Diagnosis: \nSelect and explain. \nA. Rheumatoid Arthritis, B. Rheumatic fever, C. Gouty arthritis, D. Psoariatic arthritis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (a) Rheumatoid ArthritisRef: Harrison's 18th ed. Ch. 321Clinical Features of RA* Incidence of RA increases between 25 and 55 years of age.* Gender: Female > Male* Early morning joint stiffness lasting more than 1 hour and easing with physical activity.* The earliest involved joints are typically the small joints of the hands and feet.* The wrists, metacarpophalangeal (MCP), and proximal interphalangeal (PIP) joints stand out as the most frequently involved joints. Distal interphalangeal (DIP) joint involvement may occur in RA, but it usually is a manifestation of coexistent osteoarthritis.", 'role': 'assistant'}]