A 40-year-old female presents to the emergency department with a 6-hour history of severe, colicky right upper quadrant abdominal pain radiating to her right shoulder, associated with nausea and vomiting. She reports similar, less severe episodes in the past after fatty meals. Physical exam reveals tenderness in the right upper quadrant and a positive Murphy's sign. What is the most appropriate next step in management?
✓ Correct Answer: Option D
The patient's symptoms and signs are highly suggestive of acute cholecystitis. An abdominal ultrasound is the initial diagnostic test of choice to confirm the diagnosis by visualizing gallstones, gallbladder wall thickening, and pericholecystic fluid.