Preliminary Diagnosis: Large Bowel Obstruction
I. What imaging technique is first-line for this diagnosis
-
CT with IV and PO contrast
II. Describe the advantages and disadvantages of this technique for diagnosis of large bowel obstruction.
Advantages
-
High sensitivity and specificity for large bowel obstruction
-
Identifies transition point of obstruction
Continue Reading -
Identifies degree of obstruction (low grade, high grade, or complete)
-
Can identifiy complications from obstruction (i.e., perforation, bowel ischemia)
-
May identify cause of large bowel obstruction (e.g., neoplasm, inflammatory disorder, volvulus), which will often affect clinical management
Disadvantages
-
Exposure to ionizing radiation
III. What are the contraindications for the first-line imaging technique?
-
If a complete or high grade obstruction is suspected, then PO contrast should not be given.
-
Due to radiation exposure, CT should be used conservatively in the pediatric population and is contraindicated in pregnancy.
IV. What alternative imaging techniques are available?
-
Plain radiograph
-
Barium enema
V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of large bowel obstruction.
Plain radiograph
Advantages
-
May show large bowel dilatation, which can be diagnostic of large bowel obstruction
-
Can also demonstrate signs of complications from obstruction (e.g., pneumoperitoneum)
Disadvantages
-
Typically does not provide the cause, degree, or precise location of obstruction, which would often affect clinical management
-
Often not diagnostic
Barium enema
Advantages
-
Can clearly identify transition point in sigmoid originating large bowel obstructions.
Disadvantages
-
Does not provide any information on extracolonic abnormalities, which would identify cause of large bowel obstruction
-
Does not provide evidence of mural changes or complications from obstruction
-
Exposure to ionizing radiation
VI. What are the contraindications for the alternative imaging techniques?
Plain radiograph
-
No significant contraindications; may require consent for pregnant patients at some institutions
Barium enema
-
Contraindicated if perforation suspected
Copyright © 2017, 2013 Decision Support in Medicine, LLC. All rights reserved.
No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.