Diagnostic Considerations
Conditions that should be considered when evaluating a patient with large-bowel obstruction (LBO) include constipation, cecal or sigmoid volvulus, intussusception, intestinal perforation, acute colonic pseudo-obstruction (ACPO; Ogilvie syndrome), mesenteric and mesenteric artery ischemia. As noted earlier, incarcerated hernias are a frequently missed cause of bowel obstruction, particularly left-sided inguinal hernias in which colon obstruction occurs with the sigmoid colon incarcerated in the hernia. [14]
Suspect bowel perforation in patients with persistent unexplained tachycardia, fever, or abdominal pain. In addition, malignancy, such as colorectal carcinoma, should be considered for all patients who present with large-bowel obstruction.
Differential Diagnoses
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This chest radiograph demonstrates free air under the diaphragm, indicating bowel perforation in a patient with large-bowel obstruction. Radiograph courtesy of Charles J McCabe, MD†.
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Abdominal (kidney-ureter-bladder [KUB]) film of a patient with obstipation. Dilatation of the colon is associated with large-bowel obstruction. Radiograph courtesy of Charles J McCabe, MD†.
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Gastrografin study in a patient with obstipation reveals colonic obstruction at the rectosigmoid level. Radiograph courtesy of Charles J McCabe, MD†.
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Contrast study demonstrates colonic obstruction at the level of the splenic flexure, in this case due to carcinoma. Radiograph courtesy of Charles J McCabe, MD†.
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Abdominal (kidney-ureter-bladder [KUB]) radiograph depicting massive dilatation of the colon due to a cecal volvulus. Radiograph courtesy of Charles J McCabe, MD†.
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Contrast study of patient with cecal volvulus. The column of contrast ends in a "bird's beak" at the level of the volvulus. Radiograph courtesy of Charles J McCabe, MD†.
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Massive dilatation of the colon due to a sigmoid volvulus. Radiograph courtesy of Charles J McCabe, MD†.
