Necrotizing enterocolitis (NEC) is the most common life threatening surgical and medical emergency affecting the gastrointestinal tract encountered in the neonatal intensive care unit. NEC occurs in 2-5% of all preterm infants although the majority of cases develop in infants less than 36 weeks of gestational age. It has been noted that infants born at earlier gestational age, develop NEC at a later chronological age. The average age of onset of disease is 20.2 days for infants born less than 30 weeks of gestation whereas disease onset is reduced to 13.8 days for infants born at 31-33 weeks and 5.4 days for infants born after 34 weeks of gestation. Epidemiological studies have identifi ed multiple risk factors for NEC, although a history of hypoxia, asphyxia and the introduction of enteral feeding are characteristically associated with premature infants that develop NEC. Despite its predilection for premature infants, NEC has also been described in term infants particularly those with cyanotic heart disease. There is no clear evidence to suggest that geographical origin, ethnicity or gender alter the incidence of NEC. NEC is characterized by intestinal inflammation accompanied by epithelial barrier disruption, bacterial overgrowth and submucosal invasion. In its most severe form, NEC is characterized by full-thickness destruction of the intestinal wall leading to intestinal perforation, peritonitis, sepsis and death. Although the overall mortality for patients with NEC ranges from 10% to 50%, it approaches 100% in infants with the most severe form of the disease, characteristically the smallest and most premature infants. Moreover, infants that recover from NEC may still require prolonged hospitalization due to complications from disease, such as intestinal obstruction due to scarring, short bowel syndrome and complete intestinal failure further impacting long-term survival, growth and development.
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