Necrotizing Enterocolitis (NEC)

Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed

Etiology/Pathophysiology:
Prematurity, perinatal stress, intestinal hypoxemia, and infection combine to cause intestinal necrosis that can lead to perforation. The most commonly affected areas are the terminal ileum and ascending colon, although any part of the GI tract can be involved. Complications include perforation and post inflammatory intestinal strictures.

Pathology:
Intestinal necrosis which can be superficial or transmural, unifocal or multifocal.

Imaging Findings:
Often the first highly suspicious radiographic sign of NEC is a persistent asymmetric dilation of a loop of bowel.

The classic radiographic triad is pneumatosis intestinalis, portal venous gas, and free air.

Pneumatosis is seen first in the submucosa where it looks like multiple bubbly cystic lucencies next to the bowel wall, and then it extends into the subserosa where it looks like linear lucencies which clearly outline the bowel lumen. Submucosal pneumatosis is difficult to distinguish from an intraluminal mixture of stool and gas.

Portal venous gas is seen in approximately 5% of patients and is caused by invasion of intramural gas into the intestinal venous system with migration to the liver. Portal venous gas appears as branching lucencies in the liver and is distinguished from gas in the biliary tree by being more peripheral in location than biliary tree gas, which is more central. Portal venous gas can also be seen as foci of increased echogenicity inside the liver on ultrasound.

Pneumoperitoneum is a sign of bowel perforation, which most commonly occurs in the ileocecal region.

Post inflammatory strictures most commonly develop in the colon, and are best demonstrated by barium enema.

DDX:

• Not applicable

References:

• Correlapedia

Section Top | Title Page

URL: http://www.virtualpediatrichospital.org/