July 21, 2010

Colonic Closed Loop Obstruction

Supine radiographic study of a 41-year-old woman shows a focally dilated loop of large bowel (star) in the right side of the abdomen. There is little gas in the more distal colon.
Axial CT image shows a dilated right colon (star) with a transition point with a 'whirl-like' appearance (shown on contiguous images) in the mid abdomen (arrow). The rest of the colon is not dilated. Findings are most concerning for closed loop obstruction.

Facts: Closed Loop Obstruction of the Colon
  • Colonic obstruction is rarely caused by postoperative adhesion (less than 1%). It is most commonly due to tumor
  • CT should be the next imaging work-up to look for a mass. Contrast enema should be omitted due to the risk of perforation
  • Closed loop obstruction of the colon usually is due to volvulus, which can be sigmoid (80%), cecal (15%) or involving the transverse colon (5%). Long mesocolon can predispose to malrotated cecum and result in a bascule or volvulus
  • Signs of closed loop obstruction on imaging include focally dilated bowel loop with little gas distally and proximally, transition point with a whirl-like appearance at the mesenteric root, mesenteric haziness and free fluid
Our case: transverse colonic closed loop obstruction due to extralong colonic mesentery

Halpert RD. Gastrointestinal imaging case review series, 2nd ed, 2008.

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