Necrotizing Enterocolitis

Objectives

After completing this article, readers should be able to:

1. Define the pathophysiology of necrotizing enterocolitis (NEC).

2. Explain the relationship among minimal enteral nutrition, subsequent feedings, and NEC.

3. List the factors that render human milk enteral feedings protective against NEC.

4. Explain what measures should promote advances in mortality and morbidity associated with NEC in the near future.

5. Describe the complications of NEC.

Introduction

Necrotizing enterocolitis (NEC) is one of the most serious and devastating diseases encountered in the neonatal intensive care unit (NICU). It is the most common gastrointestinal malady in neonates. It affects 1% to 8% of all infants admitted to the NICU and has a mortality rate of 10% to 50%. NEC accounts for at least 1,000 deaths annually in the United States. The increased incidence of NEC over the past few decades may be attributable to advancements in perinatal care, which have allowed very preterm infants to survive long enough to develop NEC.

The only consistently defined risk factor for NEC is prematurity; the incidence varies inversely with birthweight and gestational age. NEC strikes 4% to 13% of all very low-birthweight babies (<1,500 g). Although NEC primarily affects preterm infants, 5% to 28% of cases occur in term and near-term babies. The disease is rare in older children.

Asphyxia, congenital heart disease, polycythemia, umbilical catheterization, and the use of indomethacin and methylxanthines have been proposed as risk factors, although none has been shown to have a consistent association with NEC.

The age of onset of NEC also varies inversely with gestational age. In term infants, the median age at onset is 2 days; the preterm infant may develop the disease at several weeks of age. The risk remains high in preterm infants until they reach 35 to 36 weeks postconceptional age. The disparity in age of onset between term …