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Necrotising Enterocolitis

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Overview

Necrotising enterocolitis (NEC) is one of the most common causes of death in premature or very low birth weight infants and is a life-threatening emergency characterised by inflammation, bacterial invasion, and necrosis of the intestines. As NEC progresses, bowel perforation can occur, leading to peritonitis, sepsis, shock, and death.

Epidemiology

  • NEC is more common in premature or very low birth weight infants
  • Term infants can still develop NEC, but this is much less often
  • NEC tends to occur in the 2nd-3rd weeks of life

Risk Factors

  • Foetal risk factors:
    • Prematurity
    • Low birth weight
    • Congenital heart disease (e.g. patent ductus arteriosus)
    • Congenital gastrointestinal disorders (e.g. gastroschisis)
  • Maternal risk factors:
    • Illicit drug use
    • Chorioamnionitis
    • HIV
    • Placental abruption
  • Other risk factors:
    • Formula-feeding, breast milk seems to protective

Presentation

Overview

NEC is generally seen in the 2nd-3rd weeks of life and features are often non-specific:

  • Feeding intolerance
  • Abdominal distention
  • Bloody stools
  • Vomiting which may contain bile
  • Generally unwell
  • Absent bowel sounds

If perforation occurs, peritonitis and shock may be present, and the neonate is severely unwell with:

  • Apnoea
  • Respiratory distress
  • Temperature instability
  • Lethargy
  • Bradycardia

Investigations

Overview

  • Abdominal X-ray – the investigation of choice and should be performed as soon as the diagnosis is suspected
    • May show:
      • Dilated bowel loops
      • Bowel wall thickening
      • Pneumatosis intestinalis – gas in the bowel wall
      • Pneumoperitoneum if perforation has occurred

Other investigations may include:

  • Full blood count (FBC):
    • May show thrombocytopenia and/or neutropenia suggesting severe disease
  • C-reactive protein:
    • Non-specific marker of inflammation, may be elevated
  • Blood gases:
  • Blood cultures:
    • Sepsis may be present

Management

Overview

If NEC is suspected, neonates are initially made nil by mouth and given IV fluids and total parenteral nutrition to rest the bowel, along with IV antibiotics.

Surgery is commonly performed to remove the dead bowel tissue, although some infants may recover with medical treatment alone. If a large amount of bowel is removed, babies may be given a temporary stoma.

Complications

  • Perforation – which leads to peritonitis, sepsis and shock and mortality approaches 100%
  • Short bowel syndrome after surgery
  • Abscess formation
  • Recurrence – rare

Prognosis

  • Neonates requiring surgery have higher mortality rates (up to 30%)
  • If perforation occurs, mortality rates approach 100%

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