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large bowel obstruction


  • obstruction of the large bowel results in proximal dilatation (and potentially dilatation of small bowel) with inability to pass faeces or flatus.
  • excessive distension may result in perforation and peritonitis
  • closed loop obstructions may strangulate leading to infarction and perforation.
  • true mechanical obstruction must be differentiated from pseudo-obstruction which may result from:


AXR findings of large bowel obstruction

  • dilated colon, especially a dilated caecum
    • caecum is normally < 9cm wide, and becomes at risk of perforation if > 12cm
    • remainder of colon is normally < 6cm wide, and becomes at risk of perforation if > 9cm
  • small bowel dilatation (in 25% of cases due to reflux through the ileocaecal valve)
  • air-fluid levels in the colon, especially distal to the hepatic flexure
lbo.txt · Last modified: 2011/01/07 16:42 (external edit)