Synopsis
Recognise arterial embolic, arterial thrombotic, venous and non-occlusive mesenteric ischaemia before peritonitis, obtain immediate CT angiography despite a normal early lactate, and coordinate revascularisation, anticoagulation and bowel viability surgery.
- Severe abdominal pain out of proportion to early examination is the classic clue, but older, sedated or critically ill patients may present with delirium, diarrhoea, bleeding or unexplained organ failure.
- Arterial embolism is associated with atrial fibrillation or cardiac thrombus; arterial thrombosis with atherosclerosis; venous thrombosis with thrombophilia or inflammation; non-occlusive disease with low flow and vasoconstriction.
- A normal lactate, pH or D-dimer cannot exclude early bowel ischaemia; laboratory abnormalities often mark advanced disease.
- Request urgent CT angiography with arterial and portal-venous assessment and make the suspicion explicit; non-contrast CT or routine portal-venous imaging may miss the vascular diagnosis.
- Do not delay clinically necessary contrast because kidney function is unknown when bowel survival is at stake; resuscitate and involve radiology.
- Immediate care includes ABCDE, analgesia, careful crystalloid, broad antibiotics, nil by mouth and therapeutic anticoagulation unless contraindicated, alongside urgent operative and vascular planning.
- Restore mesenteric blood flow as early as possible using endovascular, open or hybrid techniques, while resecting only clearly non-viable bowel and considering a second look.
- Peritonitis, perforation or shock indicates infarcted bowel until proven otherwise and demands emergency laparotomy with critical-care support.
Key red flags
Sudden severe diffuse pain with minimal early tenderness in a person with atrial fibrillation, recent infarction or embolic disease should trigger immediate CTA.
A history of postprandial pain and weight loss followed by abrupt persistent pain suggests thrombosis of established mesenteric atherosclerosis.
More gradual pain, bowel-wall oedema or bleeding with thrombophilia, malignancy, pancreatitis, portal disease or inflammation suggests venous outflow obstruction.
A critically ill patient on vasopressors develops distension, feeding intolerance, acidosis or unexplained deterioration; abdominal pain may be absent.
Peritonism, shock, severe metabolic acidosis, pneumatosis with poor enhancement, portal venous gas or perforation indicates advanced injury requiring immediate laparotomy.
Investigation priorities
Acquire arterial and portal-venous phases urgently to identify arterial or venous occlusion, non-occlusive vasospasm, bowel viability and alternative pathology.
Management branches
Disproportionate pain or high-risk deterioration raises mesenteric ischaemia before peritonism.
- Use ABCDE, provide analgesia, obtain access and bloods, and call senior general and vascular surgery while requesting immediate CTA by name.
- Do not allow a normal lactate or unavailable creatinine to delay a life-saving scan; communicate cardiac, vascular and low-flow risks to radiology.
- Start broad antibiotics, nil by mouth and careful fluid resuscitation, and give therapeutic heparin unless bleeding or another contraindication is identified.
- Move directly from CTA to the endovascular, hybrid or open revascularisation plan.