A colonoscopy is a screening technique designed to discover the presence of colorectal polyps and cancer. Colonoscopies facilitate the diagnosis and prevention of colorectal cancer. During the procedure, the doctor examines the colon and rectum for polyps or abnormal growths. According to the American Cancer Society, the risks associated with colonoscopies are rare.
Oral Laxative Reactions
The oral laxatives used to induce bowel cleansing the day before the colonoscopy procedure may cause nausea, bloating, rectal irritation and vomiting.
Sedative Reactions
Some patients have a negative reaction to the sedative used during the colonoscopy. Mild problems include cramping and gas pains after the colonoscopy procedure. Other sedative-related risks include breathing difficulties, changes in heart rhythms and low blood pressure. Sedative-related complications occur in six out of every 10,000 colonoscopies, according to Medline Plus, a website of the National Institutes of Health.
Excessive Bleeding
The American Cancer Society reports that patients may notice blood in the stool a day or two after the colonoscopy procedure. Excessive bleeding, however, is a complication experienced by seven out of 1,000 patients receiving a colonoscopy, according to Medline Plus. Excessive bleeding typically stems from the site of biopsy or polyp or abnormal growth removal performed during the colonoscopy.
Perforations
Perforations are the result of tearing in the lining of the colon or rectum. Corrective surgery may be required to repair the damage. Medline Plus estimates that between one and three out of every 1,000 colonoscopies involve perforations.
Infections
An extremely rare risk from colonoscopies is bacterial infection. Antibiotics can successfully treat the infection.
