Published on 19/07/2015 by admin

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Last modified 19/07/2015

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 SB > 3 cm on plain films, 2.5 cm on CT

image Air-fluid levels on upright and decubitus films


• SB or colonic obstruction
• Intestinal pseudoobstruction
• Ogilvie syndrome
• Aerophagia


• Postoperative ileus is most common cause of delayed discharge from hospital

image Usually resolves spontaneously in 3-7 days
• Most common signs/symptoms

image Tympanic abdomen on percussion, lack of flatus
image Gaseous distension, abdominal pain, nausea, and vomiting
image Absence of bowel sounds on auscultation
• Treatment

image Treat underlying etiology (e.g., hypokalemia, sepsis)
image IV fluids, nasogastric suction


• Pitfalls: Ileus plus ascites, and recent bowel surgery mimic SBO on plain films

image CT can be used to resolve issue if necessary
(Left) Supine abdominal radiograph in an 88-year-old man with abdominal distension and hypokalemia from diuretic use shows proportional dilation image of the large and small bowel with no clear transition point. The ileus resolved with electrolyte replacement.

(Right) Supine radiograph in a 90-year-old woman with abdominal distension and pain following a hip “pinning” shows gaseous dilation of the colon image and the small bowel image in a uniform pattern with no point of transition.
(Left) This 52-year-old woman has cirrhosis with increasing abdominal distention and nausea. A supine abdominal film, requested to evaluate possible SBO, shows dilated transverse colon image and small bowel image, but no gas in other colon segments. Ascites image fills the pelvis and paracolic gutters.

(Right) CT in the same patient shows ascites image and fluid-distended bowel image. Gas fills only a portion of the nondependent bowel, while the dependent SB & colon image are fluid-filled & less dilated. This may be misinterpreted as SB obstruction.



• Adynamic ileus


• Proportional gaseous dilatation of large and small bowel (SB) due to lack of intestinal peristalsis, not mechanical obstruction


General Features

• Best diagnostic clue

image Proportional dilatation of large and small intestine on plain films with no transition point
• Location

image Large and small bowel
• Size

image Small bowel > 3 cm

Imaging Recommendations

• Best imaging tool

image Plain abdominal radiography, including supine and upright or decubitus views

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