Abstract
The most salient dilemma in the post-surgical patient with abdominal distention and feeding intolerance is whether the bowel is obstructed. If the index of suspicion is high the questions of whether it is a functional or mechanical obstruction and where is the location of the obstruction needs to be addressed. If there is no bowel obstruction the diagnostic question turns towards the location and cause of the suspected ileus. The definitive cause of abdominal distention and feeding intolerance may be due to a variety of factors that include mechanical or functional small or large bowel obstruction, adynamic/paralytic ileus, or sepsis from a variety of causes including both intra- and extra-peritoneal etiologies. Radiographic studies play an important role in determining the etiology, evaluating for complications, and in monitoring resolution once the cause has been treated. The initial radiographic examination for evaluation and triage of patients with abdominal distention is the plain abdominal film. Computed tomography is the imaging modality of choice to confirm the diagnosis of small bowel obstruction and to identify its cause. If the initial radiograph or CT is inconclusive the differential diagnoses of low-grade, partial SBO or of an ileus should be considered and an imaging technique with increased sensitivity and specificity for distinguishing between the two has to be selected. Functional studies can reveal subclinically obstructed segments. This chapter will cover all these issues in detail.