6 optical colonoscopy complications every radiologist should know

When patients report symptoms following an optical colonoscopy, radiologists often rely on CT to determine the problem. A recent analysis published in the American Journal of Roentgenology reviewed some of the complications that can be seen by CT.

Robin B. Levenson, MD, and colleagues from the department of radiology at the Beth Israel Deaconess Medical Center in Boston, wrote the review, saying it is “imperative for appropriate diagnosis and subsequent patient management” that all radiologists are up to speed.

“As the number of people in the population older than 50 years continues to rise, the number of patients undergoing optical colonoscopy will likely increase as well,” the authors wrote. “Although serious optical colonoscopy complications are uncommon, reportedly in 0.1–0.3 percent of cases overall and in up to 5 percent of cases after biopsy, polypectomy or other therapeutic procedure, they can be life-threatening if not quickly recognized.”

Levenson et al. noted that more than 14 million optical colonoscopies are performed in the U.S. each year, so radiologists have a good chance of eventually encountering every type of complication, no matter how rare it may be.

The authors wrote about six potential complications in detail:

1. Bowel perforation

Levenson and colleagues said bowel perforation is rare, but when it does occur, it can usually be traced to one of three causes: “direct trauma from diagnostic colonoscopy, barotrauma from overinsufflation and perforation from therapeutic intervention.” They also noted that patients suffering from perforation often present with abdominal pain.

“Early symptoms include persistent abdominal pain and possibly abdominal distention,” the authors wrote. “The patient may also have fever, leukocytosis and subsequent peritonitis, raising concern for sepsis. Patients may also present with subcutaneous gas or gas tracking into the chest or elsewhere, possibly leading to pneumomediastinum or pneumothorax.”

Surgery is often necessary in cases of bowel perforation.

2. Postcolonoscopy hemorrhage

Hemorrhages are the most common complication following an optical colonoscopy, and patients who have previously undergone polypectomy are a greater risk. The good news for patients is that it rarely requires surgery.

“Treatment of hemorrhage after colonoscopy includes repeat optical colonoscopy with clipping, epinephrine injection or both in stable patients or angiography with embolization, particularly in less stable patients,” the authors wrote.

3. Postpolypectomy Syndrome

Postpolypectomy syndrome is “relatively rare,” according to Levenson and colleagues, but it’s not pretty.

“Electrocoagulation injury to the bowel wall from electrical current applied during polypectomy induces a transmural burn and localized peritonitis without evidence of perforation on imaging examinations,” the authors wrote. “Patients typically present within 12 hours with abdominal pain and tenderness, but symptoms may present up to 5 days after the procedure. Patients may also have fever, leukocytosis and tachycardia, which can clinically mimic bowel perforation.”

Abdominal and pelvic CT, the authors add, can help specialists tell the difference between postpolypectomy syndrome and bowel perforation. And if a complication is determined to be postpolypectomy syndrome, it can be treated with “bowel rest, IV hydration and possible antibiotics.”  

4. Splenic injury

Splenic injury is rare, but has a mortality rate of 5 percent.

“Only approximately 100 cases of splenic injury from optical colonoscopy have been reported in the literature to our knowledge,” the authors wrote. “Although the exact mechanism is unknown, three possibilities have been proposed. One proposed mechanism is excessive traction on the splenocolic ligament, which may cause partial capsular avulsion or splenic tears. Other theorized mechanisms of splenic injury from optical colonoscopy are direct trauma from navigation of the splenic flexure by the colonoscope and excess traction on splenocolic adhesions that developed from prior surgeries or other intra-abdominal inflammatory processes.”

Symptoms of splenic injury following an optical colonoscopy include left upper quadrant abdominal pain and dizziness, and such symptoms are typically presented within 24 hours of the procedure. There have been cases, however, where symptoms were delayed.

Most splenic injuries are treated with a splenectomy, data shows, while some are treated “conservatively” and a very small number are treated with splenic artery embolization.

5. Appendicitis

Appendicitis is another rare complication of optical colonoscopies, but 28 such cases have been documented to the authors’ knowledge.

“The pathophysiology is not well understood, but a few mechanisms have been suggested,” the authors wrote. “They include barotrauma from overinsufflation, direct trauma from accidental intubation of the lumen of the appendix causing inflammation, compression of stool into the appendix that may cause obstruction or inflammation, and exacerbation of subclinical disease. Additionally, preexistent appendicoliths may be present that, combined with appendiceal trauma from optical colonoscopy, may predispose to appendicitis.”

Appendicitis following an optical colonoscopy is treated the same as traditional cases of appendicitis: with surgery.

6. Diverticulitis

Diverticulitis is also uncommon after an optical colonoscopy, yet not as rare as splenic injury or appendicitis.

“This abnormality is thought to result from microperforation from increased intraluminal pressures, direct trauma or possibly inflammation resulting from displacement of retained stool into a diverticulum,” the authors wrote.

Patients in these cases are often treated with “antibiotics, hydration and symptom relief,” but image-guided drainage or surgery are required in more extreme cases.