A 72-year-old male patient presents to the emergency department with severe lower abdominal pain and an inability to void for the past 12 hours. On physical examination, the patient's bladder is palpable and distended. Which of the following is the most appropriate initial intervention for this patient?
Immediate bladder catheterization
Administration of analgesics
Begin intravenous fluids to encourage diuresis
Perform an ultrasound to confirm bladder distention