Unusual Causes of Abdominal Pain after Colonoscopy: A Case Series

Abstract

Purpose: Colonoscopy has an overall complication rate of 0.2-0.35%. These include preparation related complications, colonic perforation, post-polypectomy hemorrhage or coagulation syndrome, and other less common complications. Abdominal pain post-colonoscopy occurs 5-11% of the time. Though the cause is usually minor, we are most concerned about colonic perforation or post-polypectomy coagulation syndrome. However, this is not always the case. We report three separate cases of uncommon causes of abdominal pain after colonoscopy: acute diverticulitis, incarcerated umbilical hernia, and acute gangrenous cholecystitis. A 59 yo male with iron-deficiency underwent colonoscopy. Within two days, he developed LLQ pain and fever. CT abdomen revealed acute sigmoid diverticulitis. A 60 yo female with a history of colon polyps underwent colonoscopy. She presented the same day with an incarcerated umbilical hernia requiring surgical repair. A 75 yo male with a history of colon polyps underwent colonoscopy. He presented the same day with RUQ abdominal pain and was found to have acute cholecystitis. Surgical pathology revealed gallstones & gangrenous cholecystitis. Of the three conditions described above, only acute diverticulitis has been directly linked to colonoscopy with an incidence of 0.56/1000 exams within 7 days and 0.84/1000 exams within 30 days. There are four reports of cholecystitis and one report of incarcerated umbilical hernia post-colonoscopy in the literature. Diverticulitis post-colonoscopy likely results from a microperforation secondary to barotrauma or mechanical forces. Umbilical hernia incarceration is likely related to increased intra-abdominal pressure following colonic air distention forcing the small bowel into the hernia and compromising the blood supply. Regarding acute cholecystitis, possible mechanisms include diminished bile flow and gallbladder distention from lithogenic bile resulting from prep-related dehydration and/or bacterial translocation from mechanical forces and colonic manipulation. In one report, E. faecalis and Clostridium spp were isolated from the pericholecystic fluid. It seems likely that there is causality and not mere coincidence given the timing and possible mechanisms to explain the complications above. Given the minimal number of cases reported, additional studies correlating the incidence of incarcerated umbilical hernia or acute cholecystitis with colonoscopy, as has been described with acute diverticulitis, would be helpful. As gastroenterologists, we must be aware that not all cases of abdominal pain after colonoscopy are due to perforation or post-polypectomy coagulation syndrome and other less common etiologies must be considered.