Necrotising Enterocolitis (NEC)
Why is this topic important?
Necrotising Enterocolitis (NEC) is the most common gastrointestinal emergency in neonates and one of the highest-yield neonatal topics in MRCPCH examinations.
Candidates should be able to:
Recognise risk factors
Identify early symptoms
Interpret abdominal X-rays
Understand medical and surgical management
Recognise complications
NEC frequently appears in FOP, TAS and AKP examinations.
Definition
Necrotising Enterocolitis is an inflammatory condition causing intestinal injury, necrosis and, in severe cases, bowel perforation.
It primarily affects preterm infants.
Key MRCPCH Facts
NEC is the commonest neonatal gastrointestinal emergency.
Prematurity is the most important risk factor.
Human breast milk reduces the risk.
Pneumatosis intestinalis is the hallmark radiological finding.
Abdominal X-ray is the key initial investigation.
Intestinal perforation may require surgery.
Early recognition improves outcomes.
Epidemiology
Most cases occur in:
Preterm Infants
Particularly:
<32 weeks gestation
Very low birth weight infants
Risk increases as gestational age decreases.
Pathophysiology
Immature intestine
↓
Abnormal bacterial colonisation
↓
Mucosal injury
↓
Inflammation
↓
Intestinal necrosis
↓
Perforation (severe disease)
Risk Factors
Prematurity
Most important risk factor.
Formula Feeding
Higher risk compared with breast milk.
Intestinal Ischaemia
May contribute to bowel injury.
Abnormal Gut Colonisation
Associated with NICU environment.
Severe Illness
Examples:
Sepsis
Hypoxia
Congenital heart disease
Clinical Features
Presentation is often subtle initially.
Feeding Intolerance
Often earliest sign.
Abdominal Distension
Very common.
Increased Gastric Aspirates
Vomiting
May become bilious.
Blood-Stained Stools
Highly suggestive.
Apnoea and Bradycardia
Especially in preterm infants.
Temperature Instability
Lethargy
Suggests systemic involvement.
Examination Findings
Distended Abdomen
Abdominal Tenderness
Abdominal Discolouration
Late sign.
Reduced Bowel Sounds
Signs of Shock
In severe disease.
Differential Diagnosis
Neonatal Sepsis
Intestinal Obstruction
Examples:
Malrotation
Volvulus
Hirschsprung Disease
Spontaneous Intestinal Perforation
Investigations
Abdominal X-Ray
Most important investigation.
Important MRCPCH fact.
Classic Findings
Pneumatosis Intestinalis
Gas within the bowel wall.
Hallmark feature.
Portal Venous Gas
Suggests severe disease.
Pneumoperitoneum
Indicates perforation.
Blood Tests
FBC
May show:
Thrombocytopenia
Neutropenia
CRP
Often elevated.
Blood Culture
If sepsis suspected.
Blood Gas
May show:
Metabolic acidosis
Raised lactate
Bell Staging (Simplified)
Stage I
Suspected NEC
Feeding intolerance
Mild abdominal distension
Stage II
Definite NEC
Pneumatosis intestinalis
Systemic illness
Stage III
Advanced NEC
Shock
Perforation
Severe metabolic disturbance
Management
Stop Enteral Feeds
First step.
Nasogastric Decompression
Reduces bowel distension.
Intravenous Fluids
Maintain hydration.
Broad-Spectrum Antibiotics
Essential treatment.
Local guidelines should be followed.
Monitor Closely
Including:
Blood gases
Abdominal examination
Serial X-rays
Surgical Referral
Required if:
Perforation
Worsening clinical condition
Fixed abdominal mass
Surgical Management
May involve:
Peritoneal Drain
Or
Laparotomy
Depending on clinical condition.
Complications
Intestinal Perforation
Most important acute complication.
Short Bowel Syndrome
Following bowel resection.
Intestinal Strictures
May develop weeks later.
Growth Failure
Neurodevelopmental Impairment
More common in severe disease.
Prevention
Human Breast Milk
Most effective protective factor.
Important MRCPCH fact.
Standardised Feeding Protocols
Careful Advancement of Feeds
Infection Prevention Measures
In NICU.
Common Exam Traps
Trap 1
Prematurity is the strongest risk factor.
Trap 2
Blood-stained stools should raise suspicion.
Trap 3
Pneumatosis intestinalis is the hallmark radiological sign.
Trap 4
Breast milk reduces NEC risk.
Trap 5
Pneumoperitoneum suggests perforation.
Trap 6
Do not continue enteral feeds when NEC is suspected.
One Minute Revision
Commonest neonatal GI emergency.
Prematurity is the main risk factor.
Feeding intolerance and abdominal distension are common.
Blood-stained stools are important.
Abdominal X-ray is key.
Pneumatosis intestinalis = hallmark sign.
Stop feeds immediately.
Start antibiotics.
Watch for perforation.
Related Question of the Day
A 28-week infant develops abdominal distension and blood-stained stools. Abdominal X-ray demonstrates gas within the bowel wall. What is the most likely diagnosis?
A. Hirschsprung disease
B. Malrotation
C. Necrotising Enterocolitis
D. Pyloric stenosis
E. Gastro-oesophageal reflux
Answer
C. Necrotising Enterocolitis
Explanation
Pneumatosis intestinalis (gas within the bowel wall) is the hallmark radiological feature of NEC.
Related Topics
Neonatal Sepsis
Respiratory Distress Syndrome
Hypoglycaemia
Patent Ductus Arteriosus
Apnoea of Prematurity
Suggested References
Rennie & Roberton's Textbook of Neonatology
Nelson Textbook of Pediatrics
BAPM Guidance
BNF for Children
Neonatal Life Support (NLS) Manual
European Society for Paediatric Gastroenterology (ESPGHAN)
Disclaimer
These notes are intended for MRCPCH revision and educational purposes only. They do not replace local, national or institutional guidelines. Clinical decisions should always be based on current guidance, senior advice and individual patient circumstances.
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