A 70-year-old female undergoes an elective total knee arthroplasty. On post-operative day 2, she develops fever (38.5°C), shortness of breath, and a productive cough. Chest X-ray shows new infiltrates in the right lower lobe. Her oxygen saturation is 90% on room air. What is the most likely diagnosis and initial management?
✓ Correct Answer: Option C
The combination of fever, dyspnea, productive cough, and new infiltrates in an elderly, post-surgical patient strongly suggests post-operative pneumonia. Initial management involves prompt initiation of broad-spectrum antibiotics, pending culture results.