A 48-year-old man is brought to hospital for a 2-day history of worsening abdominal pain and fever. He has a history of alcoholism. Physical examination shows a fluid wave. Vitals are: temperature 102 F, HR 80, RR 20, BP 120/80. Which of the following is the most appropriate next step in diagnosis?
A) CT of the abdomen
B) Endoscopic retrograde cholangiopancreatography
C) Endoscopy
D) Paracentesis
E) Ultrasound
