Synopsis
Identify the cause, level and immediate danger of large-bowel obstruction, then translate the examination and imaging into a safe intervention decision.
- Obstruction with shock, guarding or suspected bowel infarction requires immediate surgical assessment while resuscitation proceeds; imaging must not postpone necessary source control.
- Contrast-enhanced CT of the abdomen and pelvis is the principal investigation for suspected malignant obstruction and uncertain or complicated volvulus.
- Read the transition point, proximal colon, caecum, mesenteric vessels and bowel enhancement together; a normal lactate cannot establish bowel viability.
Key red flags
Tachycardia, hypotension, reduced urine output, confusion, fever or cool peripheral perfusion indicate a patient who needs urgent resuscitation and senior review. Dehydration can coexist with sepsis. Interpret these signs against premorbid observations, medication effects and the speed of deterioration.
Persistent focal pain, new caecal tenderness, guarding or rebound changes a distension problem into possible ischaemia or perforation. Request immediate surgical reassessment even if an earlier examination was reassuring. Analgesia is appropriate, but reassess the abdomen and physiology after treatment.
Investigation priorities
Identify a transition, its cause, bowel perfusion and complications in a patient stable enough for scanning.
Management branches
A patient presents with marked distension and possible large-bowel obstruction.
- Call the surgical team, keep the patient nil by mouth, establish intravenous access and assess shock, peritonitis and aspiration risk. Resuscitate and provide appropriate analgesia while urgent intervention is organised.
- For a stable patient, obtain contrast-enhanced CT promptly and ask explicitly about the transition point, cause, caecal distension and bowel viability. If shock or peritonitis already mandates surgery, do not create a mandatory CT-first delay.