Examqo › Examqo library › Pediatrics › Neonatology · IMLE
Necrotising enterocolitis (NEC)
NEC is inflammatory necrosis of the bowel wall that mainly affects preterm infants once feeding has started; the diagnostic radiographic sign is gas in the bowel wall (pneumatosis intestinalis), and treatment is stopping feeds, gastric decompression and antibiotics, with surgery for perforation.
Why it matters in the exam
The classic case is an infant born before 32 weeks, in the second or third week of life, fed formula, who develops a distended abdomen, bilious gastric aspirates, bloody stools and apnoea. The question asks you to recognise the radiographic finding, determine the stage and choose the next step — and separates an X-ray showing pneumatosis (stage II) from free intra-abdominal air (stage III, perforation), which needs surgery.
Risk factors are prematurity and very low birth weight, formula feeding instead of breast milk, rapid advancement of feeds, anaemia and transfusions, and in the term infant congenital heart disease or asphyxia. Human milk (the mother's own or donor milk) is the most important preventive measure.
Laboratory tests show thrombocytopenia, metabolic acidosis and hyponatraemia — signs of deterioration. Conservative treatment includes stopping feeds, usually for 7–14 days, nasogastric decompression, broad-spectrum antibiotics and parenteral nutrition, with serial abdominal X-rays. After recovery, remember strictures (mainly in the colon) that appear weeks later, and short bowel syndrome after extensive resection.
Key points
- NEC mainly affects preterm infants after feeding starts.
- Pneumatosis intestinalis makes the diagnosis.
- Treatment: stop feeds, nasogastric decompression, antibiotics and TPN.
- Free air = perforation = surgery.
- Human milk is the most important preventive measure.
Summary table
| Stage (Bell) | Clinical finding | Imaging finding | Treatment |
|---|---|---|---|
| I — suspected | Feeding intolerance, mild distension, occult blood in the stool | Normal or dilated loops | Stop feeds, nasogastric tube, antibiotics for 3 days until the diagnosis is excluded |
| II — definite | Distended tender abdomen, bloody stools, mild acidosis | Pneumatosis intestinalis, sometimes portal venous gas | Stop feeds for 7–14 days, antibiotics, TPN |
| IIIA — advanced without perforation | Shock, DIC, severe acidosis, peritonitis | As in II with ascites | Intensive care, consider surgery |
| IIIB — perforation | Severe deterioration | Free air (pneumoperitoneum) | Laparotomy or peritoneal drain |
| Late complication | Obstruction weeks after recovery | Stricture, mainly in the colon | Contrast study and surgery as needed |
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Pediatrics, Medical licensing exam (IMLE), Pediatric surgery.
Subscriber? Read the full topic Plans and prices 25 free questions
Sources
- Nelson Textbook of Pediatrics, 22nd edition (2024) — Necrotizing Enterocolitis
- Modified Bell staging criteria for necrotizing enterocolitis (Walsh and Kliegman), 1986 (in current use) — Stages I–III
- AAP Policy Statement: Donor Human Milk for the High-Risk Infant, 2017 — Human milk and NEC prevention
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.