A colonoscopy is a medical procedure to check for abnormalities of the large intestine and rectum. A long, flexible tube with a small video camera tip is inserted into the rectum. A physician is able to see the inside of the intestine via the video camera, and he can pass biopsy instruments through the tube to collect tissue samples or remove growths on the intestinal wall. MayoClinic.com states that colonoscopy is generally safe; however, it does pose a few risks.
Sedative Reaction
A colonoscopy is performed under sedation. The person having the procedure will be put to sleep or be put in a state of semi-sleep. Some people experience reactions to sedation, including trouble breathing and a drop in blood pressure. A person undergoing a colonoscopy is medically screened before the procedure to ensure the risks of sedation are low; however, screening does not always indicate that a reaction will not occur. Mild reactions to sedation may also occur, including nausea and vomiting.
Bleeding
Polyps are growths that may develop inside the intestine. Removing polyps during a colonoscopy can help determine whether cancer may be present inside the colon. Additionally, a biopsy may be performed in which tissue samples are snipped from inside the colon to check colon health. Both of these procedures may lead to bleeding. The American Gastroenterological Association states that in some cases, heavy bleeding occurs. These cases may require aggressive measures such as reinsertion of the colonoscope to control bleeding. Severe cases of hemorrhage from a colonoscopy may require a blood transfusion.
Perforation
Perforation of the bowel or intestine may occur during a colonoscopy. Instruments used to collect tissue samples or remove growths on the intestine may cause a tear, or perforation, through the intestinal wall. Perforation of the rectum may also occur. Additional surgery may be needed to repair rectal or intestinal perforation. The University of Maryland Medical Center states that perforation occurs in about three of every 1000 colonoscopies performed.
Additional Risks
MedlinePlus states that additional risks of a colonoscopy may occur from medications used to cleanse the colon before the procedure. The colon must be free of stool before the colonoscopy can be performed. A patient must drink special solutions that cleanse the bowel beforehand. Nausea, vomiting, abdominal fullness and rectal pain or irritation may result.
