Synopsis
Recognise acute mesenteric ischaemia early, obtain definitive arterial and venous phase CT angiography without renal-function delay, and coordinate revascularisation with bowel rescue.
- Suspect AMI from the clinical trajectory: abrupt severe pain, pain disproportionate to early examination, vomiting or diarrhoea, embolic risk, atherosclerosis, venous thrombosis risk or low-flow critical illness.
- Request urgent CT angiography with contrast in arterial and venous phases, slices no thicker than 1 mm and an optional non-contrast run; ESVS recommends this regardless of renal function because delay risks fatal bowel loss.
- After CTA classifies the mechanism, give systemic unfractionated heparin when indicated and bleeding risk permits; for thrombotic or embolic SMA occlusion, consider endovascular treatment first only where expertise is immediately available and no peritonitis mandates emergency laparotomy coordinated with revascularisation.
Key red flags
Generalised guarding, rigidity, rebound tenderness, shock or organ failure indicates possible transmural necrosis and requires emergency laparotomy; imaging must not postpone source control in a crashing patient.
Sudden severe abdominal pain with little initial tenderness, atrial fibrillation, recent myocardial infarction, embolic disease or diffuse atherosclerosis should trigger urgent CT angiography rather than serial observation.
Rapid abdominal deterioration during vasopressor use, low-output cardiac failure, dialysis or critical illness can be non-occlusive mesenteric ischaemia even when no arterial occlusion is seen.
Portal venous gas, bowel-wall hypoenhancement, pneumatosis with systemic toxicity, free perforation or mesenteric arterial occlusion on CT requires immediate specialist interpretation and action.
Investigation priorities
First definitive test in every patient with suspected AMI who is being considered for active treatment; acquire contrast arterial and venous phases with at most 1 mm slices, optionally preceded by non-contrast CT.
Management branches
A patient with atrial fibrillation develops sudden central abdominal pain, vomiting and rising physiological concern despite a relatively soft abdomen.
- Treat this mismatch as suspected AMI: resuscitate, give intravenous broad-spectrum antibiotics, notify vascular and gastrointestinal surgical teams and state AMI explicitly on the CT request.
- Obtain urgent thin-slice arterial-and-venous phase CT angiography regardless of renal function; do not wait for lactate, D-dimer or creatinine normalization.
CTA demonstrates thrombotic or embolic SMA occlusion in a patient eligible for active treatment.