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Gastrointestinal: NICU Handbook

Provider Education
May 18, 2022

Steven J McElroy MD
Peer Review Status: Internally Peered Review

Neonatal necrotizing enterocolitis

  • Neonatal necrotizing enterocolitis (NEC) is an inflammatory intestinal disease of newborn infants.
  • Nationwide, NEC affects 1-3% of all NICU admissions and 7% of infants with birth weights less than 1500g
  • Mortality rate nationwide is around 20-30%
  • Incidence varies inversely with birth weight and gestational age
    • Greatest risk for infants born <30 weeks and <1000g
  • Despite a higher incidence in ELBW infants, the majority of infants do not develop NEC until after 28 weeks corrected gestation (usually 2-3 weeks after birth)

Risk factors

  • Prematurity
  • Enteral feeding
  • Bacterial colonization

Term infants

  • Up to 10% of infants who develop NEC are born at term
  • Normal rate of term infants developing NEC is 0.5%
  • Risk factors for developing NEC for term infants
    • Gastroschisis
    • Congenital Heart Disease (especially HLHS – hypoplastic left heart syndrome and TA – truncus arteriosus)
  • Term infants with Congenital Heart Disease who develop NEC have
    • Higher mortality (39-57%)
    • Earlier onset (Average age is 7 days after birth)

Prevention

  • The ONLY currently proven prevention for NEC is maternal breast milk feedings
  • Infants fed breast milk developed 6-10 times less NEC than infants fed formula alone and 3 times less than infants fed breast milk + formula

Treatment

  • Antibiotics
    • Choice of antibiotics will depend upon previous therapy, presence of invasive lines, epidemiology of the nursery, and will generally target anaerobes and gram negative organisms.  In general, begin with vancomycin and gentamicin.  Flagyl should be added in the event of a bowel perforation.
  • NPO
    • Duration of NPO depends upon the severity of the illness.  Any baby with definite NEC should be NPO for a minimum of 7 days.  All babies should receive TPN with lipids starting after the acute sepsis is resolved.
  • Orogastric Suction:
    • A large bore suction catheter tube connected to low intermittent wall suction should be started initially and maintained until distention is resolved, pneumatosis is resolved, and output is less than 10 ml/Kg/day.
  • Serial Evaluations
    • Abdominal girth
    • Serum electrolytes
    • Complete blood counts
    • Blood gases for metabolic acidosis
    • Abdominal x-rays
  • Surgery
    • Consult surgery early
    • Indications for surgery include free abdominal air, worsening clinical symptoms, signs of peritonitis
  • Currently there is no consensus literature to support routine probiotic use
  • Currently there is no literature to support direct causality between transfusions and NEC
  • Currently there is no consensus literature that donor milk is definitively preventative against NEC

References

  1. Yee, W.H., et al. Incidence and timing of presentation of necrotizing enterocolitis in preterm infants. Pediatrics 129, e298-304 (2012).=
  2. Neu, J. & Walker, W.A. Necrotizing enterocolitis. N Engl J Med 364, 255-264 (2011).
  3. Fitzgibbons, S.C., et al. Mortality of necrotizing enterocolitis expressed by birth weight categories. J Pediatr Surg 44, 1072-1075; discussion 1075-1076 (2009).
  4. Lin, P.W., Nasr, T.R. & Stoll, B.J. Necrotizing enterocolitis: recent scientific advances in pathophysiology and prevention. Semin Perinatol 32, 70-82 (2008).
  5. McElroy, S.J., Underwood, M.A. & Sherman, M.P. Paneth Cells and Necrotizing Enterocolitis: A Novel Hypothesis for Disease Pathogenesis. Neonatology 103, 10-20 (2012).