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': '40 years patient having arthritis of PIP and DIP along with carpometacarpal joint of thumb and sparing of wrist and metacarpophalangeal joint, most likely diagnosis is \nSelect and explain. \nA. rheumatoid arthritis, B. osteo arthritis, C. psoriatic arthritis, D. pseudo gout', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e.osteoarthritis Now, this form of question (where arthritic involvement of a group of joints are given) is very frequently asked:Osteoarthritis- Joints involved :PIP, DIP, Base of thumbSparing of wrist & metacarpophalangeal junction.Psoriasis: - Joints involved :PIP, DIP, Wrist, metacarpophalangeal joint.Rheumatoid arthritis - DIP is not involved characteristically.Joints involvedMetacarpophalangeal joints (MC) esp of index finger PIP, wrist, elbow, knee, ankle.", 'role': 'assistant'}]