[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Paediatric pathology](https://durgical.com/en/general-pathology/#a-pediatric) › Necrotizing enterocolitis: why the premature gut is vulnerable [General pathology](https://durgical.com/en/general-pathology/) · [Paediatric pathology](https://durgical.com/en/general-pathology/#a-pediatric) # Necrotizing enterocolitis: why the premature gut is vulnerable - Mechanism In the preterm baby, an immature gut, newly arrived bacteria and feeding combine into an inflammation that can kill the bowel wall. Updated 2026-11-01 ## Key points - Risk is inversely proportional to gestational age; most cases occur in preterm infants who are already being fed. - Commonest site: terminal ileum, caecum and ascending colon. - Characteristic X-ray sign: pneumatosis intestinalis (gas in the wall); also portal venous gas, and pneumoperitoneum if it perforates. - Feeding with breast milk lowers the risk compared with formula. - Sequelae: intestinal strictures and short bowel syndrome after resections. ## What it is Necrotising enterocolitis is the commonest acquired gastrointestinal emergency of the newborn and affects mainly preterm infants after enteral feeding starts. Its cause is multifactorial: an immature mucosal barrier, an exaggerated immune response to the flora and unstable blood flow. Breast milk is the main protective factor. ## Structure - Gross: distended, friable, congested or gangrenous loops; sometimes perforated. - Microscopy: mucosal oedema and haemorrhage, coagulative necrosis that may be transmural, inflammation and gas bubbles in the submucosa. - In the repair phase, granulation tissue and fibrosis appear and may narrow the lumen. ## Step by step - The preterm gut has loose tight junctions, little mucus and slow motility. - Enteral feeding begins and a poorly diverse bacterial flora colonises the lumen. - Bacteria activate epithelial receptors (such as TLR4), which are highly expressed in the immature gut. - Cytokines and platelet-activating factor are released: inflammation, epithelial injury and vasoconstriction. - Bacteria and their products cross the barrier; ischaemia and infection kill the mucosa and then the whole wall. - The necrotic wall may perforate, causing peritonitis and sepsis. ## Clinical notes - Feeding intolerance, abdominal distension, bilious gastric residuals and blood in the stools. - Systemic signs: apnoea, temperature instability, lethargy and, in severe cases, shock. - Advanced or perforated forms need surgery. ## Memory aid Immature gut, new bacteria and milk that is not the mother's: three sparks that set the bowel wall on fire. ## Test yourself Think of the answer, then tap the question to see it. ## What is the characteristic X-ray sign of necrotising enterocolitis? Pneumatosis intestinalis: gas inside the bowel wall. ## Which segment of bowel is most often affected? The terminal ileum and the proximal colon (caecum and ascending colon). ## Which feeding factor protects against necrotising enterocolitis? Breast milk, which supplies IgA, lactoferrin and oligosaccharides that favour a healthy flora. ## Which sequel can follow an extensive bowel resection for this disease? Short bowel syndrome, with malabsorption. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/general-pathology/necrotizing-enterocolitis-why-the-premature-gut-is-vulnerable/) ## Related - [Prematurity and fetal growth restriction](https://durgical.com/en/general-pathology/prematurity-and-fetal-growth-restriction/) - [Infarction: red vs white, and what decides the damage](https://durgical.com/en/general-pathology/infarction-red-vs-white-and-what-decides-the-damage/) - [Patterns of necrosis: coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous](https://durgical.com/en/general-pathology/patterns-of-necrosis-coagulative-liquefactive-caseous-fat-fibrinoid-gangrenous/) - [Hypoxia, ischemia and reperfusion injury](https://durgical.com/en/general-pathology/hypoxia-ischemia-and-reperfusion-injury/) ## Related conditions - [Necrotising enterocolitis](https://durgical.com/en/conditions/necrotising-enterocolitis/) - [Prematurity and its complications](https://durgical.com/en/conditions/prematurity-and-its-complications/) - [Short bowel syndrome](https://durgical.com/en/conditions/short-bowel-syndrome/) - [Neonatal sepsis](https://durgical.com/en/conditions/neonatal-sepsis/) - [Small bowel obstruction](https://durgical.com/en/conditions/small-bowel-obstruction/) ## Elsewhere in DurgiPedia - [Neonatal immunity: maternal IgG and breast-milk IgA](https://durgical.com/en/immunology/neonatal-immunity-maternal-igg-and-breast-milk-iga/) - [Splanchnic and portal circulation](https://durgical.com/en/physiology/splanchnic-and-portal-circulation/) - [Small intestine: villi, crypts, enterocytes, Paneth cells; duodenum vs jejunum vs ileum](https://durgical.com/en/histology/small-intestine-villi-crypts-enterocytes-paneth-cells-duodenum-vs-jejunum-vs-ile/) - [Enteroendocrine cells and GALT](https://durgical.com/en/histology/enteroendocrine-cells-and-galt/) - [Pattern recognition: PAMPs, DAMPs, Toll-like receptors](https://durgical.com/en/immunology/pattern-recognition-pamps-damps-toll-like-receptors/) [← 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: [Necrotizing enterocolitis: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001148.htm) (MedlinePlus, US National Library of Medicine, 2026); [Preterm birth](https://www.who.int/news-room/fact-sheets/detail/preterm-birth) (World Health Organization, 2026). ## **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/necrotizing-enterocolitis-why-the-premature-gut-is-vulnerable/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/necrotizing-enterocolitis-why-the-premature-gut-is-vulnerable/