Necrotizing Enterocolitis

  • Etiology: multifactorial – bowel ischemia / paralysis / bacterial invasion leading to ulceration, mainly affects colon + ileum
  • AXR: early (diffusely dilated loops of bowel / ileus, asymmetrically dilated loop of bowel), later (classic triad of pneumatosis intestinalis, portal venous gas, free air), fixed loop can be sign of impending perforation, some perforations can be walled off due to surrounding inflammation and not show free air on AXR, many cases have no AXR findings as some findings of necrotizing enterocolitis on AXR are transient (pneumatosis intestinalis + portal venous gas)
    — Bubbly pneumatosis = submucosal gas, curvilinear pneumatosis = subserosal gas
    — Note: biliary air is more central in liver, portal venous gas is more peripheral in liver
  • US: complicated ascites + free air are signs of perforation, portal venous gas appears as echogenic bubbles in portal veins, pneumatosis intestinalis
  • Complications: strictures in 25%, more common in colon than small bowel, especially in left colon
  • Clinical: stricture should be suspected in an infant with a persistently distended abdomen after treatment for necrotizing enterocolitis

Cases of Necrotizing Enterocolitis

AXR of necrotizing enterocolitis
Supine AXR shows diffusely dilated loops of bowel throughout the abdomen. There is no evidence of pneumatosis intestinalis, portal venous gas, or free air.
AXR of necrotizing enterocolitis
Supine AXR shows linear pneumatosis intestinalis involving several loops of bowel in the left lower quadrant of the abdomen.
AXR of necrotizing enterocolitis
Supine AXR shows numerous branching linear lucencies throughout the liver consistent in appearance with portal venous gas.
Enema of necrotizing enterocolitis
AP image from an enema shows two fixed strictures in the colon, the first at the junction of the sigmoid colon and descending colon, and the second at the splenic flexure.
Surgical image of necrotizing enterocolitis
Surgical image shows the bowel was white and necrotic throughout its entire length from the duodenum to the colon. There was no salvageable bowel.