MSFinals-5400

MSFinals-5400

A 38-year-old man presents to the Emergency Department complaining of epigastric pain. The patient reports that he developed acute abdominal pain 2 hours prior to presentation after eating a cheeseburger. The patient otherwise has no significant past medical history. He does not take any medications and denies smoking, alcohol consumption and drug use. He has been recently been released from prison and has not got stable living and has had to sleep outside since his release.
On examination, the patient has normal vital signs. His abdominal examination demonstrates normoactive bowel sounds, no tenderness to palpation in the epigastrium and no guarding or rebound tenderness. Rectal exam for stool occult blood is negative and a chest X-ray does not reveal free air under the diaphragm. A right upper quadrant ultrasound does not demonstrate stones. The doctor recommends antacids. When the doctor tells the patient that he is safe for discharge, the patient insists that he must be admitted to hospital for further tests.
Which of the following is the most likely diagnosis?