A colonoscopy is a common screening and diagnostic test that can find colon cancer and other problems in the large intestine, according to the American Society for Gastrointestinal Endoscopy. It is an outpatient procedure that often requires a mild sedative. The doctor inserts a tube with an attached scope into the rectum, and gently snakes it up through the colon so that he can see any abnormalities. If he spots an abnormality, he can insert an instrument into the tube to take a sample for testing. He can also remove any polyps--small growths that are usually benign, but can lead to cancer. If there is bleeding, he can use drugs or heat to stop it. Complications from this procedure are rare.
Bleeding
If a biopsy is performed or a polyp removed, there is a chance of bleeding, according to the American Society for Gastrointestinal Endoscopy. This bleeding is usually minor and may stop without intervention, but it can be very heavy. The doctor may cauterize bleeding blood vessels or use drugs to control the bleeding during the procedure. However, sometimes a follow-up procedure or a blood transfusion is required. The risk of bleeding is higher in older patients or in those with chronic conditions like high blood pressure or diabetes, according to the Annals of Internal Medicine.
Colon Injury
Sometimes the scope used to perform the test tears or punctures the wall of the colon, according to the American Society for Gastrointestinal Endoscopy. This is a serious complication that may require surgery to repair. But it is rare, occurring only about three times in every 1000 colonoscopies, according to the Annals of Internal Medicine. However, older patients or those with chronic health problems are at a higher risk of this complication.
Other Complications
If a sedative is used, it may trigger an allergic reaction in some patients, according to the American Society for Gastrointestinal Endoscopy. There is also a risk that the procedure itself will aggravate existing conditions like heart or lung disease. Also, even with an experienced physician, there is a risk that some abnormalities or signs of cancer could be missed, according to the American Gastroenterological Association.
Symptoms
If complications do occur after a colonoscopy, they can cause abdominal pain, fever or chills, and rectal bleeding, according to the American Society for Gastrointestinal Endoscopy. Bleeding can be a sign of a complication even if it happens several days later. Those affected by these symptoms should contact their doctors.
