[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Gastrointestinal tract](https://durgical.com/en/general-pathology/areas/gi/) › Ischaemic bowel disease # Ischaemic bowel disease - Lesion When blood flow to the bowel drops, the lining dies first; a sudden block of a major artery can kill the whole wall. Updated Nov 12, 2026 ## Key points - Causes of arterial occlusion: atherosclerotic thrombosis at vessel origins, emboli from cardiac mural thrombi (atrial fibrillation) or aortic atheroma, vasculitis. - Venous thrombosis: hypercoagulable states, tumours, cirrhosis, compression. - Non-occlusive: heart failure, shock, dehydration, vasoconstrictor drugs (cocaine). - Watershed zones: splenic flexure (superior and inferior mesenteric territories meet) and rectosigmoid. - Surface epithelium dies before the crypts because capillaries reach the surface last: surface atrophy with preserved or hyperproliferative crypts is the signature. - Right-sided colonic ischaemia carries a worse prognosis (superior mesenteric territory). ## What it is The gut is supplied by the coeliac, superior mesenteric and inferior mesenteric arteries, with collaterals that tolerate slow narrowing but not sudden occlusion. Ischaemic damage ranges from mucosal infarction (above the muscularis mucosae) to mural (mucosa and submucosa) to transmural infarction of all layers. Transmural infarction usually follows acute thrombosis or embolism; mucosal and mural infarcts follow hypoperfusion. Much of the injury happens at reperfusion. ## Structure - Acute transmural infarct: sharply demarcated, intensely congested, dusky to purple-red bowel; later bloody mucus in the lumen, rubbery oedematous wall. - Coagulative necrosis of the muscularis propria within one to four days; perforation and fibrinopurulent serositis may follow. - Mucosal infarct: haemorrhagic, ulcerated, segmental and patchy mucosa. - Micro: atrophic or sloughed surface epithelium, crypts preserved; neutrophils arrive after reperfusion. - Chronic ischaemia: fibrotic lamina propria and, uncommonly, stricture; superinfection can create pseudomembranes. ## Step by step - Blood flow falls from arterial blockage, venous thrombosis or low cardiac output. - The tips of villi and the surface epithelium become hypoxic first. - Reperfusion brings free radicals and neutrophils, and bacterial products leak across the barrier. - Damage deepens from mucosa to submucosa to muscle if the cause persists. - Transmural necrosis leads to perforation, peritonitis and sepsis. ## Clinical notes - Acute colonic ischaemia: sudden cramping left lower abdominal pain, urgency and bloody diarrhoea, mostly in people over seventy. - Acute mesenteric ischaemia: pain out of proportion to the examination; signs of infarction appear late. - Other ischaemic patterns: CMV endothelial infection, radiation enterocolitis, necrotizing enterocolitis of premature infants. ## Memory aid Surface first, crypts last; watershed at the flexure and the rectosigmoid. ## Test yourself Think of the answer, then tap the question to see it. ## Why is the surface epithelium more vulnerable to ischaemia than the crypts? Capillaries run from the crypt toward the surface before turning back, so the surface receives the least oxygenated blood; crypt stem cells are protected. ## Which two colonic watershed zones are most prone to ischaemic colitis? The splenic flexure and the rectosigmoid region. ## What usually causes transmural intestinal infarction? Acute arterial obstruction by thrombosis (atherosclerosis) or embolism (cardiac mural thrombus, aortic atheroma). [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/general-pathology/ischaemic-bowel-disease/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Connections ## Related 8 - [Intestinal obstruction](https://durgical.com/en/general-pathology/intestinal-obstruction/) - [Angiodysplasia](https://durgical.com/en/general-pathology/angiodysplasia/) - [Pseudomembranous colitis: C. difficile toxins and the volcano lesion](https://durgical.com/en/general-pathology/pseudomembranous-colitis-c-difficile-toxins-and-the-volcano-lesion/) - [Infarction: red vs white, and what decides the damage](https://durgical.com/en/general-pathology/infarction-red-vs-white-and-what-decides-the-damage/) - [Hypoxia, ischemia and reperfusion injury](https://durgical.com/en/general-pathology/hypoxia-ischemia-and-reperfusion-injury/) - [Necrotizing enterocolitis: why the premature gut is vulnerable](https://durgical.com/en/general-pathology/necrotizing-enterocolitis-why-the-premature-gut-is-vulnerable/) - [Watershed areas and the organs most sensitive to ischemia](https://durgical.com/en/general-pathology/watershed-areas-and-the-organs-most-sensitive-to-ischemia/) - [Systemic (arterial) thromboembolism](https://durgical.com/en/general-pathology/systemic-thromboembolism/) ## Related conditions 9 - [Acute mesenteric ischaemia](https://durgical.com/en/conditions/acute-mesenteric-ischaemia/) - [Ischaemic colitis](https://durgical.com/en/conditions/ischaemic-colitis/) - [Chronic mesenteric ischemia](https://durgical.com/en/conditions/chronic-mesenteric-ischemia/) - [Necrotising enterocolitis](https://durgical.com/en/conditions/necrotising-enterocolitis/) - [Hypovolaemic shock](https://durgical.com/en/conditions/hypovolaemic-shock/) - [Atherosclerosis and dyslipidaemia](https://durgical.com/en/conditions/atherosclerosis-and-dyslipidaemia/) - [Atrial fibrillation](https://durgical.com/en/conditions/atrial-fibrillation/) - [Portal vein thrombosis](https://durgical.com/en/conditions/portal-vein-thrombosis/) - [Cytomegalovirus infection](https://durgical.com/en/conditions/cytomegalovirus-infection/) [← All of general pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Acute Mesenteric Ischemia](https://www.ncbi.nlm.nih.gov/books/NBK431068/) (StatPearls (NCBI Bookshelf), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/general-pathology/ischaemic-bowel-disease/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/ischaemic-bowel-disease/