Bowel obstruction / Ileus

What are the sites of bowel obstruction?

• Small bowel
• Large bowel

What is ileus?

Dilated bowel which may be from:

• Paralytic
• Obstructive

What are the common causes of ileus?

• Paralytic ileus occurs when there is inflammation in the peritoneum, most often following abdominal surgery; or other inflammations, like appendicitis, pancreatitis, etc.
• Normal postoperative ileus lasts 48 hours.
• The absence of bowel sounds, flatus, or bowel movements beyond the expected period indicates delayed resolution, or obstructed ileus.

What are the common causes of small bowel obstruction?

• Post-op adhesions
• Gallstone ileus
• Intussusseption
• Tumors

What are the common causes of large bowel obstruction?

• Cancer colon
• Fecal impaction
• Diverticulitis

What are the anticipated imaging findings of bowel obstruction?

• Dilated loops of bowel 
• Air fluid levels in the small bowel loops.

Plain film in a case with Small bowel obstruction Multiple dilated small bowel loops are seen (white arrowheads). There is fecal material in the right and left colon (arrows). Air is seen in the rectum. The surgical staples indicate recent abdominal surgery. (black arrowheads).

Small bowel obstruction Cross lateral view shows multiple dilated fluid filled loops of bowel with air fluid levels.

CT scan of another patient showing findings of bowel obstruction:
A: Post op changes in abdominal wall. Arrowheads: Normal size of distal small bowel and Recto sigmoid (RS) B: Arrowheads: Dilated small bowel loops. Arrow: Area of obstruction

Lower GI in a patient with Large bowel Obstruction Dilated bowel loops proximal to the obstruction. Arrow points to the etiology of obstruction.