S4002 Between a Tumor and a Hard Place: Post-Colonoscopy Bowel Perforation in a Patient With Peritoneal Carcinomatosis

Introduction: Post-colonoscopy perforation is an uncommon occurrence, with an incidence of less than one per thousand for diagnostic colonoscopy.1 The use of carbon dioxide insufflation rather than air is one of many strategies to reduce barotrauma and risk of perforation.2 Both water immersion and carbon dioxide insufflation are generally considered safe.3 This is a case of post-colonoscopy colon perforation after use of water immersion to proceed past a sigmoid stricture caused by extrinsic carcinomatosis. Case Description/Methods: A 49-year-old woman with history of invasive left lobular breast carcinoma and prior small bowel obstruction (SBO) presented with abdominal pain with imaging revealing a transition point in the terminal ileum and thickening of the terminal ileum and colon. A severe 8 mm stricture was noted in the sigmoid colon on prior flexible sigmoidoscopy. The patient underwent colonoscopy to rule out Crohn’s disease, which revealed a non-traversable stricture in the descending/sigmoid colon with lumen of approximately 2.5 mm at the narrowest point. Water immersion was used to open the lumen and advance past the stricture point but was unsuccessful. The patient then developed severe abdominal pain requiring emergency exploratory laparotomy. A transverse colon perforation was identified, and the patient underwent diverting loop ileostomy. There were findings of omental caking consistent with metastatic breast cancer. The patient was discharged after a prolonged recovery. Discussion: Water immersion is often used to open the lumen and transverse strictures. However, in cases where the lumen is severely narrowed, water may not flow out of the stricture which causes air and fluid to be trapped in the proximal segment of the colon, creating a water seal. This patient had a transition point at the terminal ileum as well as sigmoid stricture, leaving the transverse colon susceptible to perforation if subjected to distension. In cases of stricture, carbon dioxide insufflation should be considered first to traverse the stricture, as the molecule absorbs quickly through the large bowel epithelium compared to water and thus carries a lower risk of bowel perforation. References 1. Reumkens A, Rondagh EJ, Bakker CM, Winkens B, Masclee AA, Sanduleanu S. Post-Colonoscopy Complications: A Systematic Review, Time Trends, and Meta-Analysis of Population-Based Studies. Am J Gastroenterol. 2016;111(8):1092-101. 2. Memon MA, Memon B, Yunus RM, Khan S. Carbon Dioxide Versus Air Insufflation for Elective Colonoscopy: A Meta-Analysis and Systematic Review of Randomized Controlled Trials. Surg Laparosc Endosc Percutan Tech. 2016;26(2):102-16. 3. ASGE Standards of Practice Committee; Fisher DA, Maple JT, Ben-Menachem T, et al. Complications of colonoscopy. Gastrointest Endosc. 2011 Oct;74(4):745-52. Erratum in: Gastrointest Endosc. 2016 Nov;84(5):883.