Acute colonic pseudo-obstruction

GASTROINTESTINAL ENDOSCOPY 789 This is one of a series of statements discussing the utilization of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy prepared this text. In preparing this guideline, a MEDLINE literature search was performed, and additional references were obtained from the bibliographies of the identified articles and from recommendations of expert consultants. When little or no data exist from well-designed prospective trials, emphasis is given to results from large series and reports from recognized experts. Guidelines for appropriate utilization of endoscopy are based on a critical review of the available data and expert consensus. Further controlled clinical studies are needed to clarify aspects of this statement, and revision may be necessary as new data appear. Clinical consideration may justify a course of action at variance to these recommendations. Acute colonic pseudo-obstruction (ACPO) is characterized by massive colonic dilation in the absence of mechanical obstruction; synonyms include acute colonic ileus and Ogilvie’s syndrome.1-3 Ischemia or perforation are the feared complications of ACPO; spontaneous perforation has been reported in 3% to 15% of patients with a mortality rate of 50% or higher.4 The rate of perforation and/or ischemia rapidly increases with cecal diameters >10 to 12 cm and when the duration of distention exceeds 6 days.5 In evaluating a patient with signs or symptoms of suspected acute colonic dilation (Fig. 1), mechanical obstruction should be excluded because surgical management may be required. Although initial conservative management for mechanical obstruction overlaps with the initial management of ACPO (e.g., nothing by mouth, intravenous fluids, nasogastric suction), the possibility of mechanical obstruction must always be considered particularly if there is no response to conservative management. If there is any suspicion of mechanical obstruction, a water soluble contrast enema of the rectum and distal colon should be obtained. The causes of and predisposing factors associated with the development of ACPO are multiple (Table 1). Often more than one of these factors are present. Most commonly, this syndrome is associated with intraperitoneal or extraperitoneal surgery. Multiple case reports and case-series have linked postoperative ACPO to pelvic surgery (i.e., orthopedic, gynecology, and urologic) and lumbar spine surgery.6,7 Based on LaPlace’s law, increasing diameters accelerate the rise in tension experienced by the colon wall. Although risk does increase with expanding dimensions, there is only a poor association with absolute diameters.Animal and retrospective data suggest critical thresholds of 9 cm for the transverse colon and 12 cm for the cecum; however, many patients present with dimensions greater than this without sequelae.8 American Society For Gastrointestinal Endoscopy