Colonoscopy is an endoscopic procedure to directly examine the interior of the large intestine (large bowel) from the rectum to the terminal ileum using a colonoscope. The procedure takes approximately 20–40 minutes and is usually performed as an outpatient. Diagnostic colonoscopy is recommended for alterations in bowel habits, occult or frank blood in the stool, unexplained anemia, and as a screening procedure for colon cancer.
The colon must be completely clean for colonoscopy to be thorough and safe. Patients may be placed on a liquid diet for 1–2 days before the examination and administered oral laxatives and/or enemas to clear the colon. Patients are asked to arrive at the endoscopy suite about 1–2 hours prior to the procedure and should be accompanied by a responsible adult to transport them home. The patient is registered and a medical history is documented. Then, a needle/catheter is inserted into a vein for intravenous access (allowing for fluid and sedative administration).
The videocamera on the colonoscope transmits images of the inside of the colon to a monitor. Multiple monitors in the endoscopy suite can allow for multiple examiner viewing. After the sedation is administered the physician usually performs a digital rectal exam after which the colonoscope is inserted into the rectum. The colonoscope is advanced to the cecum. During the exam, air may be introduced into the colon to improve visibility. The physician may take biopsies or remove polyps during the procedure using instruments passed through the endoscope. The tissue samples are sent to a laboratory for analysis. If there is bleeding in the colon the physician has a variety of instruments at his disposal to treat bleeding. There is no pain involved with these procedures.
On completion of the examination, patients remain in the recovery area for 1–2 hours until the effects of the medication wear off. The physician will inform the patient about the results of the colonoscopy and provide additional information as needed. Patients are discharged with instructions to have limited activity for the remainder of the day. Walking may help relieve bloatedness or gas.
Colonoscopy is safe and effective when performed by professionals with appropriate training and experience. Complications are rare (1:10,000). Complications may include bleeding from a biopsy site or perforation (a tear in the bowel wall). Symptoms of abdominal pain, distention, nausea, vomiting, chills, fever or rectal bleeding should be reported to the physician.
Instructions for Colonoscopy Preparation