Colonoscopy Practice and Quality: Colonoscopy Practice and Quality: Adverse Events

0:00Welcome to Board Pearls. This is episode four of five of the Colonoscopy Practice and Quality chapter, in the Endoscopic Procedures module. This episode is what can go wrong after a polyp comes out, and how each problem is recognized and managed. The first patient is a woman with a large cecal resection who takes aspirin, and her case shows who bleeds after polypectomy and when, what's done about it, which defects should be clipped closed to prevent bleeding and which shouldn't, and how a perforation is closed and when it needs a surgeon. The second patient is a man with fever after a hot snare, and his case shows the complication that looks like a perforation but isn't. A woman with left shoulder pain after a difficult colonoscopy shows the complication that happens away from the polyp altogether.

0:43Here's the first patient. She's the sixty-three-year-old woman from episode two, whose thirty-five-millimeter cecal lesion was removed by endoscopic mucosal resection, EMR, with the nodule taken in one piece and the margins treated with snare-tip soft coagulation. Her defect is large and proximal. She takes aspirin for secondary prevention after a coronary stent eight years ago.

1:07Her large proximal defect and her aspirin put her at risk of post-polypectomy bleeding. Post-polypectomy adverse events are recognizable and largely manageable when caught early, and each has a specific anatomic or thermal mechanism that decides its management. Bleeding occurs after zero point three to two point five percent of polypectomies overall, and the risk rises sharply with polyp size, hot snare use, and antithrombotic drugs. Her lesion is large, and her aspirin continues anyway, because it's for secondary prevention after a stent. Aspirin is continued through nearly all procedures in that setting, because stent thrombosis is far deadlier than procedural bleeding, which can usually be treated at the scope.

1:46Her bleeding risk comes in two forms, separated by timing, and each is managed differently. Immediate bleeding is seen from the polypectomy site during the procedure and is managed then: with hemoclips that close the visible vessel, thermal coagulation with the snare tip or coagulation forceps, or epinephrine injection, which constricts vessels and tamponades by mass effect. It's the easier form to manage, because the source is in view. Delayed bleeding presents one to fourteen days later as hematochezia after a recent polypectomy. It's often self-limited but sometimes brisk, and it's managed by repeat colonoscopy with endoscopic hemostasis on the polypectomy scar, which is still recognizable.

2:26Her defect is clipped closed before the scope is withdrawn, because she's exactly the patient in whom closure prevents delayed bleeding. Prophylactic clip closure of large EMR defects in the proximal colon reduces delayed bleeding. In a randomized trial of polyps twenty millimeters or larger, clip closure substantially reduced delayed bleeding from proximal lesions, with about sixteen patients closed to prevent one bleed, while distal lesions showed no benefit. Clips bring the defect edges together, protect the exposed submucosal vessels from luminal acid and mechanical stress while they heal, and speed mucosal healing. Her defect, after a lesion over twenty millimeters in the cecum, is the kind the trial showed benefit for. The same lesion in the sigmoid wouldn't be expected to benefit, so defects aren't closed by reflex.

3:13Closure lowers her risk without removing it, and five days later she has two episodes of maroon stool, a heart rate of ninety-eight, and a hemoglobin fall of one and a half grams. She has delayed post-polypectomy bleeding, inside the one-to-fourteen-day window. Her repeat colonoscopy shows a clip off one end of the defect and a visible vessel, which is clipped, and her bleeding stops. Under the adverse event lexicon covered in chapter twenty-eight, that's a moderate event, because it needed repeat endoscopic treatment.

3:45Her large resection also carried a risk of perforation, and when it's found decides how it's treated. Perforation follows zero point zero five to zero point one percent of diagnostic colonoscopies and rises to one percent or more for therapeutic procedures such as large EMR, endoscopic submucosal dissection, and dilation. During the procedure, it's recognized by seeing the muscularis propria or structures outside the colon through the defect. After the procedure, it presents with peritoneal signs, fever, leukocytosis, and free air on imaging. A perforation recognized during the procedure and smaller than two centimeters is closed endoscopically, with through-the-scope clips, over-the-scope clips, or endoscopic suturing, with success in more than ninety percent of published cases. That works because a fresh perforation hasn't yet meaningfully contaminated the peritoneum, the tissue is fresh enough to clip, and prompt closure prevents the contamination that would otherwise force an operation. Larger or older perforations, those with established peritoneal contamination, and those in positions that can't be closed need surgery.

4:51Her case shows how the same hole can be managed in opposite ways. Had an eight-millimeter defect showing structures beyond the muscle appeared during her resection, it would have been clipped closed then, very likely sparing her an operation. Had she instead come back two days later with diffuse peritonitis, fever, and free air, that would be a delayed perforation with established contamination, and she'd go to surgery, because the advantage of a fresh hole in a clean field is gone. That difference is why a large resection defect is inspected for perforation before the scope comes out.

5:24The second patient's symptoms look like a perforation, and the scan is what separates them. He's the forty-seven-year-old man from episodes one and three, whose twenty-two-millimeter pedunculated sigmoid polyp was removed with a hot snare. Thirty-six hours later he has a fever of thirty-eight point five, focal left lower quadrant tenderness, and a white count of fourteen thousand. His computed tomography, CT, shows no free air.

5:49He has post-polypectomy electrocoagulation syndrome, not a perforation. Post-polypectomy electrocoagulation syndrome, also called post-polypectomy syndrome, is a transmural thermal injury that doesn't perforate but mimics perforation. It follows about half a percent to one percent of hot snare polypectomies and presents with fever, focal peritoneal signs in the right or left lower quadrant, and leukocytosis twenty-four to seventy-two hours after the procedure. The muscularis propria is injured but not breached, so the discriminator from perforation is the absence of free air on imaging. He had a hot snare, his symptoms began inside the window, his tenderness is focal over the polypectomy site, and his CT shows no free air.

6:32His management is conservative, because there's no hole to close. It's bowel rest, intravenous antibiotics covering colonic flora, and observation, and most patients improve over two to five days without surgery. He's admitted, kept nothing by mouth, and given intravenous antibiotics, and by day three his fever has gone and he's eating. His CT changed his course: with free air, he'd have needed surgical consultation and possibly an operation. The electrosurgical energy his thick stalk needed is what put him at risk of this syndrome, which is one reason cold snare is the default for small polyps, as episode two covers.

7:08One more complication happens away from the polyp site, which is why it's easy to miss. A seventy-year-old woman had a difficult colonoscopy with repeated looping at the splenic flexure. That evening she has left upper quadrant pain spreading to her left shoulder, and her blood pressure is falling. She has a splenic injury, a rare but recognized adverse event caused by traction on the attachments between the colon and the splenic capsule. The shoulder pain is the Kehr sign, from irritation of the diaphragm, and imaging shows free fluid. Her blood pressure decides her management. A stable patient with a contained injury is observed, while an unstable patient with active bleeding, like her, needs splenic artery embolization or splenectomy.

7:50Taken together, the location and timing of symptoms after colonoscopy point to the cause. Right or left lower quadrant tenderness with fever a day or two after a hot snare, without free air, suggests post-polypectomy syndrome. Diffuse peritonitis with free air means perforation. Hematochezia days later means delayed bleeding. And left upper quadrant and shoulder pain with hypotension after a difficult examination means the spleen.

8:17Here are the traps the boards set in these patients. Secondary-prevention aspirin isn't stopped to prevent post-polypectomy bleeding. Delayed bleeding is managed with repeat colonoscopy rather than watchful waiting alone. Large proximal defects of twenty millimeters or more are clipped closed, and distal defects aren't closed expecting a benefit. A small perforation recognized during the procedure is closed endoscopically rather than sent straight to surgery. A delayed perforation with peritonitis goes to surgery rather than endoscopic closure. Fever and focal tenderness after a hot snare without free air is post-polypectomy syndrome, and it isn't operated on. And left upper quadrant and shoulder pain after a difficult examination points to splenic injury.

9:03So, start to finish. Manage immediate bleeding at the time with clips, coagulation, or epinephrine, and delayed bleeding, one to fourteen days later, with repeat colonoscopy. Clip closure of proximal defects twenty millimeters or larger prevents delayed bleeding, while distal defects don't benefit.

9:23Close a perforation recognized during the procedure and smaller than two centimeters endoscopically, with success in more than ninety percent, and send delayed or large perforations with peritonitis to surgery. Fever and focal tenderness twenty-four to seventy-two hours after a hot snare, without free air, is post-polypectomy syndrome, treated with bowel rest and antibiotics. Left upper quadrant pain with a Kehr sign after a difficult examination suggests splenic injury, managed by observation, embolization, or splenectomy depending on stability.

9:55Episode five, the last of the chapter, is colonoscopy in special populations.

10:01For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode four of five of chapter thirty, and I'll see you in the next one.