A 63-year-old female patient presents with abdominal pain, vomiting, and abdominal distention. She has previously had a cholecystectomy and hysterectomy. She has had no prior similar episodes, and denies fever, hematemesis, or diarrhea. She takes no medications. Vital signs include blood pressure 123/61 mm Hg, heart rate 97, oral temperature 37.2°C, respiratory rate 18, oxygen saturation 97% on room air. Her abdomen is diffusely tender and distended.