Complications

Complication
Timeframe
Likelihood
short term
medium

The finding of distal polyps (adenomatous or hyperplastic) or of high-risk polyps increases the risk of synchronous malignancy. Any finding of adenomatous polyps or of large or multiple hyperplastic polyps should prompt full colonoscopic evaluation.

short term
low

The incidence of perforation is 0.58 per 1000 colonoscopies, and the risk of bleeding is 2.4 per 1000 colonoscopies.[27]

Colonoscopic polypectomy is associated with an increased risk of bleeding compared with colonoscopy alone. Risk factors for post-polypectomy bleeding include: increasing polyp size, larger number of polyps removed, recent warfarin therapy, right-sided colon location, and hyperplastic histology.[27]

Patients usually complain of abdominal discomfort or pain within a few hours of their endoscopy, and often the endoscopist recognises a higher-risk procedure or perforation itself at the time of endoscopy and will opt for longer than usual observation of the patient post-procedure.

Diagnosis of this complication is made using erect chest radiography or CT to demonstrate extra-intestinal air within the abdomen.

Treatment can be conservative, with antibiotics and supportive management. Alternatively, treatment can be surgical, during which wash-out of the abdominal cavity with or without repair of the perforation can be carried out via laparotomy or laparoscopy.

short term
low

A polyp causing obstruction through intussusception will be excised with the bowel at the time of resection, or if the obstruction is treated conservatively in the first instance (e.g., using an air enema), it will be removed endoscopically thereafter.

long term
low

Adenomatous polyps have a significant risk of malignant transformation. Prevention of this complication is by identification and endoscopic excision of adenomas on asymptomatic screening or in response to symptoms, and then by post-polypectomy surveillance colonoscopy.

Colorectal cancer

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