Acute Appendicitis – Diagnosis and Management

A 22-year-old male presents with 8 hours of right lower quadrant pain, fever (38.5°C), and anorexia. On examination, he has tenderness at McBurney's point with a positive Rovsing's sign. His white blood cell count is 13,500/μL with left shift. Ultrasound shows a non-compressible, dilated appendix of 8 mm with echogenic periappendiceal fat. What is the most appropriate next step in management?