MSFinals-6472
A 35-year-old woman arrives at the emergency department complaining of intense epigastric pain and non-bilious vomiting that has persisted for two days. She reports retching but no longer brings anything up. During the examination, the surgical registrar observes abdominal distension and widespread guarding and rigidity. The registrar requests the insertion of a nasogastric tube, but three attempts fail. What is the probable diagnosis?