A colonoscopy is a diagnostic procedure performed to examine the inner lining of the colon, or large intestine, and the rectum. The colonoscopy procedure is performed routinely in patients who are age 45 or above as a means detecting colorectal cancer in its early stages. It is also employed diagnostically to help determine the cause of abnormal bowel activity, abdominal pain or rectal bleeding. During a colonoscopy, tissue samples may be collected for a biopsy, and polyps or other abnormal growths may be removed.
Reasons for a Colonoscopy
Colonoscopies are recommended for people who are at increased risk of developing colorectal cancer. This type of cancer is much more effectively treated when it is detected early. Individuals at increased risk of developing colon cancer include those who:
- Have a personal or family history of colorectal polyps
- Have a personal or family history of colorectal cancer
- Have a personal or family history of inflammatory bowel syndrome (IBS)
- Are obese or have a poor diet
- Smoke or consume alcoholic beverages to excess
- Have diabetes
- Do not exercise regularly
All individuals over the age of 50 should undergo regular colonscopies and the procedure may be recommended for younger patients at elevated risk, whether they are experiencing symptoms or not.
Preparing for a Colonoscopy
In order to prepare for a colonoscopy, the colon must be cleansed so that its inner surface will be visible. Prior to the colonoscopy, patients are given written instructions which may vary a bit from one physician to another. Typically, the patient is told to drink clear liquids for a day or two before the procedure, including water, tea, coffee, strained fruit juices, sports drinks and clear broths. Patients are also permitted to consume gelatin. One strict prohibition is any liquid or gelatin with a red or purple coloration.
The day before the procedure, patients are instructed to drink a quantity of a special laxative solution or to take a large number of laxative pills. It is important that the patient remain close to home during this day because the toilet must be available for frequent use.
Patients who take aspirin or other blood-thinning medication must advise their doctors before going through the colonoscopy procedure. Most other medications can be continued.
The Colonoscopy Procedure
A colonoscopy is generally performed as an outpatient procedure. The patient is positioned on the left side and a sedative is administered intravenously. Once the patient is sedated, a colonoscope, a thin flexible tube with a camera attached to it, is gently inserted into the rectum. The colonoscope is then carefully snaked into the lower portion of the large intestine and guided upward toward the lowest portion of the small intestine. This enables the gastroenterologist to clearly visualize the entire length of the colon. Vital signs are closely monitored throughout the procedure.
The doctor watches the procedure on a computer monitor in real time, and is able to see any abnormalities clearly. If necessary, tiny instruments will be inserted through the colonoscope to enable the surgeon to removed any polyps or other abnormal growths for biopsy. The procedure usually takes between 30 and 60 minutes to perform.
Recovery from a Colonoscopy
After the colonoscopy procedure, the patient is kept for observation for up to 2 hours, until the sedative wears off. Reflexes and judgment may be impaired and driving is not permitted for 24 hours after the procedure. Some people may experience pressure, bloating, nausea or cramping in the abdomen after the procedure, but these side effects are temporary. The patient should expect to expel an unusually large amount of gas after the procedure. This is considered normal.
Risks of a Colonoscopy
A colonoscopy is a safe, effective procedure. Nonetheless, as with any medical procedure, there is a slight risk of complication. Risks of a colonoscopy include:
- Infection
- Abdominal pain
- Excessive bleeding
- Perforation of the bowel wall
- Adverse reaction to sedative medication
Despite the unpleasantness of the preparation and the very slight chance of a mishap during the procedure, the colonoscopy is an invaluable diagnostic tool that has saved countless lives.
Colonoscopy FAQs
1. What is a colonoscopy?
A colonoscopy is a diagnostic procedure performed to examine the inside of the colon and rectum.
2. Why is a colonoscopy performed?
The colonoscopy procedure can aid in determining the cause of changes in bowel activity, abdominal pain, rectal bleeding, as well as detect early signs of cancer. A colonoscopy may be recommended as an option for people who are at risk of developing cancer of the colon and rectum, known as colorectal cancer, or CRC.
3. How can I prepare for the procedure?
Patients will be given a set of written instructions to follow. A clear liquid diet should be followed for 1 to 3 days prior to the procedure. Depending on the instructions provided, a laxative or enema may be required. Patients may need to drink a special bowel cleansing solution, the day before the procedure. Most medications can still be taken, although some such as aspirin or blood thinners may require special instructions.
4. What can I expect during a colonoscopy?
Before the colonoscopy procedure, an intravenous, or IV, with a light sedative will be used to make the patient comfortable. Vital signs will be monitored throughout the procedure. The patient will lie on their left side as the colonoscope is inserted into the anus and guided to the opening of the small intestine. The colonoscope is then slowly withdrawn from the colon and the lining of the colon is examined carefully by the physician. The removal of polyps, or growths, for biopsy may also be conducted during the procedure. The colonoscopy procedure usually takes between 30-60 minutes to perform.
5. What happens after a colonoscopy?
After the procedure, patients will be kept under observation for up to 2 hours, until the sedative used for the procedure wears off. Reflexes and judgment may be impaired and driving is not permitted for 24 hours after the procedure. Some people may experience pressure, bloating and cramping in the abdomen after the procedure, but these effects are temporary.
6. What are the risks or complications of the procedure?
Complications of a colonoscopy are rare. If they do occur, complications can include fever, abdominal pain, dizziness, bleeding from a biopsy site, perforation of the bowel wall or a reaction to the medication used in the IV.
