Necrotising enterocolitis (NEC) is a disorder affecting premature neonates, where part of the bowel becomes necrotic. It is life-threatening due to the risk of bowel perforation, leading to peritonitis, sepsis and shock.
The cause of necrotising enterocolitis is unclear. There are certain risk factors for developing NEC:
- Very low birth weight (under 1.5kg)
- Very/extremely premature (before 32 weeks gestation)
- Formula feeding (it is less common in breast milk-fed babies)
- Respiratory distress syndrome and assisted ventilation
- Sepsis
- Patent ductus arteriosus
Presentation
Presenting features include:
- Intolerance to feeds
- Vomiting, particularly with green bile
- Generally unwell
- Distended, tender abdomen
- Absent bowel sounds
- Blood in stools
Infants with bowel perforation will be severely unwell, with peritonitis and shock.
Investigations
Blood tests include:
- Full blood count for thrombocytopenia (low platelets) and neutropenia (low neutrophils)
- CRP (raised with inflammation)
- Capillary blood gas (metabolic acidosis)
- Blood culture (to identify sepsis)
Abdominal x-ray is the initial investigation for diagnosis. The main view is anteroposterior, with the infant supine (lying on their back). Additional views may be used to help detect free gas in the abdomen, indicating perforation:
- Lateral (from the side with the infant on their back)
- Lateral decubitus (from the side with the infant on their side)
X-ray findings include:
- Dilated loops of bowel
- Bowel wall oedema (thickened bowel walls)
- Pneumatosis intestinalis refers to gas in the bowel wall
- Pneumoperitoneum refers to free gas in the peritoneal cavity and indicates perforation
- Gas in the portal veins
Management
Initial management involves:
- Nil by mouth
- IV fluids and total parenteral nutrition (TPN)
- Antibiotics
- Nasogastric tube to drain fluid and gas from the stomach and intestines
NEC is a surgical emergency and requires immediate referral to the neonatal surgical team. Some neonates will recover with medical treatment. In others, surgery may be required to remove the dead bowel tissue. They may be left with a temporary stoma if a significant section of the bowel is removed.
Complications
Short-term complications include:
- Perforation and peritonitis
- Sepsis
- Death
Long-term complications include:
- Strictures
- Abscess formation
- Recurrence
- Long-term stoma
- Short bowel syndrome after surgery
Last updated May 2025
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