A 55-year-old man with prior extensive pelvic surgery develops small bowel obstruction. CT shows dilated small bowel loops with a 'bird's beak' transition point at the terminal ileum level. No free air or free fluid is present. After 48 hours of conservative management (NG decompression, IV fluids), he develops increasing abdominal pain and leukocytosis. What is the CT feature that most reliably predicts strangulation and mandates urgent surgery?
- A Dilated bowel loops >3 cm diameter
- B A single transition point visible on CT
- C Pneumatosis intestinalis or portal venous gas ✓
- D Absence of oral contrast beyond the transition point at 24 hours
Explanation
Pneumatosis intestinalis (gas within bowel wall) and portal venous gas are radiological signs of transmural bowel ischemia/necrosis — absolute indicators of dead bowel requiring urgent surgical resection. These signs indicate bacterial translocation and gas production within ischemic bowel wall or mesenteric venous gas from the same process. Their presence in small bowel obstruction represents irreversible bowel ischemia. A single transition point indicates a mechanical cause but not necessarily strangulation. Simple bowel dilatation >3 cm reflects obstruction severity. Failure of contrast to pass is a functional indicator of obstruction but not strangulation per se.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.