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Pathology and pathogenesis of necrotizing enterocolitis in newborns

Richard J Schanler, MD
Section Editor
Steven A Abrams, MD
Deputy Editor
Melanie S Kim, MD


Necrotizing enterocolitis (NEC), the most common gastrointestinal emergency in the newborn infant, is a disorder manifested by ischemic necrosis of the intestinal mucosa [1]. It is associated with inflammation, invasion of enteric gas-forming organisms, and dissection of gas into the muscularis and portal venous system.

NEC occurs in 1 to 3 per 1000 live births and is seen predominantly in preterm infants with an incidence of approximately 6 to 7 percent in very low birth weight (VLBW) infants (BW <1500 g). Although early recognition and aggressive treatment of this disorder has improved clinical outcomes, NEC accounts for substantial long-term morbidity in survivors of neonatal intensive care, particularly in VLBW infants.

First described in 1965, the etiology of NEC remains uncertain [2-4]. Based on the available evidence, the pathology and pathogenesis of NEC are reviewed here. The clinical features, management, and prevention of this disorder are discussed separately. (See "Clinical features and diagnosis of necrotizing enterocolitis in newborns" and "Management of necrotizing enterocolitis in newborns" and "Prevention of necrotizing enterocolitis in newborns".)


The pathology of NEC is primarily due to changes from intestinal infarction [5]. The specific findings vary and depend upon the progression of the disease and the presence of underlying pathogenic factors. The terminal ileum and colon are involved in the majority of cases, although the entire gastrointestinal (GI) tract is affected in severe cases.

On gross examination, the bowel appears distended and hemorrhagic. Subserosal collections of gas occasionally are present along the mesenteric border. Gangrenous necrosis occurs on the antimesenteric border, and perforation may be present. As the gut heals, thickening of the bowel wall, fibrinous adhesions, and areas of stenosis appear.

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Literature review current through: Nov 2017. | This topic last updated: Mar 09, 2017.
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