Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 13 Sept 2026Clinical review pending
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Transmural colonic infarction
Peritonitis, shock, persistent severe pain without rectal bleeding, right-sided or pancolonic disease, perforation, gangrene or clinical deterioration suggests full-thickness injury or associated acute mesenteric ischaemia.
Action: Resuscitate, give intravenous broad-spectrum antibiotics, obtain urgent contrast CT/CT angiography when it will not delay source control, and involve colorectal and vascular teams for emergency laparotomy and resection of non-viable bowel.
Synopsis
Recognise colon ischaemia, separate stable mucosal disease from bowel-threatening infarction, and choose CT, limited endoscopy and surgery safely.
The typical presentation is sudden cramping, often left-sided abdominal pain followed within hours by urgency and bright red or maroon rectal bleeding, usually after transient hypoperfusion in an older vascular-risk patient.
Generalised peritonitis, shock, perforation or suspected gangrene requires immediate colorectal surgery and no diagnostic endoscopy; resuscitate, give intravenous broad-spectrum antibiotics and proceed to source control.
Contrast-enhanced CT is the initial imaging test in active-treatment candidates; request CT angiography when right-sided disease, severe pain without bleeding or another pattern raises acute mesenteric arterial occlusion.
Key red flags
Generalised guarding, rebound, rigidity, haemodynamic instability, rising lactate or organ failure requires emergency surgical assessment; do not perform routine endoscopy through suspected necrotic bowel.
Severe right-sided abdominal pain with little or no rectal bleeding raises concern for isolated right-colon ischaemia and possible SMA compromise; use CT angiography and involve vascular specialists.
Free intraperitoneal gas, pneumatosis with systemic toxicity, portal venous gas, absent bowel-wall enhancement or gangrene indicates advanced ischaemia and likely surgery.
Persistent bleeding, recurrent sepsis, worsening pain or failure to improve after supportive care requires reassessment for infarction, perforation, stricture or an alternative diagnosis.
Investigation priorities
01
Contrast-enhanced CT abdomen and pelvisFirst step
Initial imaging in suspected colon ischaemia when active treatment is appropriate; define distribution, severity and alternatives.
Management branches
Worked stable caseLeft-sided pain and bleeding after hypotension
After dehydration and transient hypotension, a stable older patient develops cramping left-sided pain followed by fresh rectal bleeding, without peritonism.
Resuscitate, correct the low-flow trigger, stop avoidable vasoconstrictors, rest the bowel and obtain contrast CT to define disease and exclude another emergency.
If CT and presentation remain uncertain and disease is mainly left sided, arrange limited unprepared flexible sigmoidoscopy within 48 hours using minimal insufflation; do not force passage beyond injured bowel.
Preferred severe-disease pathwayPeritonitis or gangrene
The patient has guarding, rebound, shock, free perforation, absent enhancement or other evidence of transmural injury.
National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 13 Sept 2026; clinical approval remains outstanding.