- Stomach, small intestine, gall bladder, appendix or large intestine
- Stomach: sequelae of ulcer, or less commonly, cancer
- Small bowel: ischemia, appendicitis, malignancy, necrotizing infection
- Large bowel: diverticulitis, cancer, ischemia, colitis
- Focal sx in that organ region→become generalized
- If cancer, would have more prolonged, progressive symptoms
- Infection or ischemia specific
- With perforation, patients usually very ill
- Abnormal vital signs
- Xray for free air
- CT if more subtle or identifying another primary process