A colonoscopy is a type of test in which a flexible, lighted tube called an endoscope is inserted through the anus to examine the wall of the large intestine and other …
The scope helps deliver air to allow for patient examination during a colonoscopy. The risks associated with this medical procedure can include bleeding, perforation within or outside cont…
Although not always needed, when doctors prefer to carry out further diagnostic tests before performing a colonoscopy they may use this procedure as part of their investigation. Sometimes they may also recommend taking certain medications to reduce the risk of colon cancer.
The colon opens into the rectal or pelvic cavity (or both) at a skin fold near the anus called the anal opening. The large intestine extends from the rectum and ends at the sigmoid flexure, an area on each side of this suture between the straight and twisting muscles. Another important area is the transverse or sigmoid colon where blood vessels and lymphatic vessels are located.
What Is a Colonoscopy?
Colonoscopy is a procedure that enables an examiner (usually a gastroenterologist) to evaluate the inside of the colon (large intestine or large bowel). The colonoscope is a four-foot long, flexible tube about the thickness of a finger with a camera and a source of light at its tip. The tip of the colonoscope is inserted into the anus and then is advanced slowly, under visual control, into the rectum and through the colon usually as far as the cecum, which is the first part of the colon. Usually, it also is possible to enter and examine the last few inches of the small intestine (terminal ileum).
The scope bends, so the doctor can move it around the curves of your colon. You may be asked to change position occasionally to help the doctor move the scope. The scope also blows air into your colon, which expands the colon and helps the doctor see more clearly.
You may feel mild cramping during the procedure. You can reduce the cramping by taking several slow, deep breaths during the procedure. When the doctor has finished, the colonoscope is slowly withdrawn while the lining of your bowel is carefully examined.
During the colonoscopy, if the doctor sees something that may be abnormal, small amounts of tissue can be removed for analysis (called a biopsy), and abnormal growths, or polyps, can be identified and removed. In many cases, colonoscopy allows accurate diagnosis and treatment without the need for a major operation.
What Are the Risks of a Colonoscopy?
As with any medical procedure, colonoscopy has a small risk of complications.
Approximately 5/1,000 people will have a serious complication. Complications can include a reaction to the bowel preparation or medication used for sedation, heart or lung problems, an infection, bleeding from the colon, and/or perforation of the colon (hole in the colon).
If a complication occurs, treatment including antibiotics, blood transfusion, hospitalization, repeat colonoscopy, or surgery may be required. The risk of dying from colonoscopy is less than 1/14,000. There is also a risk of missing a significant abnormality. This occurs in less than 1/10 cases.
Certain cancers may never cause any symptoms or affect life expectancy or quality of life. However, research shows that most colon cancers are harmful and that colon cancer should be detected and treated as early as possible.
How Do You Prepare for A Colonoscopy?
There may be some diet or fluid restrictions before you have a colonoscopy, but this will vary according to your doctor’s instructions. You may be asked to limit or eliminate solid foods for a few days before the test. You may also be asked to take laxatives by mouth.
Make sure you arrange for a driver to bring you home after the colonoscopy. Because you receive sedating medication during the procedure, it is unsafe for you to drive or operate machinery for 8 hours after the procedure.
What Bowel Preparation Is Needed for Colonoscopy?
If the procedure is to be complete and accurate, the colon must be completely cleaned, and there are several different colonoscopy preparations. Patients are given detailed instructions about the cleansing preparation. In general, this consists of drinking a large volume of a special cleansing solution or several days of a clear liquid diet and laxatives or enemas prior to the examination. These instructions should be followed exactly as prescribed or the procedure may be unsatisfactory (visualization of the lining of the colon may be obscured by residual stool), and it may have to be repeated, or a less accurate alternative test must be performed in its place.
Instructions may also be given to avoid certain foods for a couple of days prior to the procedure, such as stringy foods, foods with seeds, or red Jell-O.
Can I Take My Medications Before a Colonoscopy? Is There a Special Diet?
Most medications should be continued as usual, but some may interfere with the examination. It is best if the colonoscopist is informed of all current prescription and over-the-counter medications. Aspirin products, blood thinners such as warfarin (Coumadin), arthritis medications, insulin, and iron preparations are examples of medications that may require special instructions. The colonoscopist will also want to be aware of a patient’s allergies and any other major illnesses. The colonoscopist should be alerted if, in the past, patients have required antibiotics prior to surgical or dental procedures to prevent infections.
Drinking Clear Fluids
Your doctor may advise you to also drink only fluids, such as water, broth, black tea and coffee, and clear fruit juice (without pulp) for 12 to 24 hours before the test. This will help to prevent you from getting dehydrated.
Ask If You Need an Enema
A common way to clear the bowel is by using an enema. This involves inserting liquid directly into the rectum. The enema solution washes out the lower part of the bowel, and is passed into the toilet along with any faeces.
What Happens During a Colonoscopy?
Prior to colonoscopy, intravenous fluids are started, and the patient is placed on a monitor for continuous monitoring of heart rhythm and blood pressure as well as oxygen in the blood. Medications (sedatives) usually are given through an intravenous line so the patient becomes sleepy and relaxed, and to reduce pain. If needed, the patient may receive additional doses of medication during the procedure. Colonoscopy often produces a feeling of pressure, cramping, and bloating in the abdomen; however, with the aid of medications, it is generally well-tolerated and infrequently causes severe pain.
Patients will lie on their left side or back as the colonoscope is slowly advanced. Once the tip of the colon (cecum) or the last portion of the small intestine (terminal ileum) is reached, the colonoscope is slowly withdrawn, and the lining of the colon is carefully examined. Colonoscopy usually takes 15 to 60 minutes. If the entire colon, for some reason, cannot be visualized, the physician may decide to try colonoscopy again at a later date with or without a different bowel preparation or may decide to order an X-ray or CT of the colon.
You may have a colonoscopy in an outpatient setting or as part of your stay in a hospital. The way the test is done may vary depending on your condition and your health care provider’s practices.
Generally, the colonoscopy follows this process:
- You will be asked to remove any jewelry or other objects that mightget in the way during the procedure.
- You may be asked to remove your clothing and put on a hospital gown.
- An intravenous (IV) line will be inserted into your arm or hand. A sedative or a pain medicine will be injected into the IV.
- You will be given oxygen to breathe.
- Your heart rate, blood pressure, respiratory rate and oxygen level will be checked during the procedure.
- You will be asked to lie on your left side with your knees pulled up towards your chest.
- A lubricated tube will be put into your anus and moved into your rectum and colon. You may feel mild pain, pressure or cramping during the procedure. A sedative is used to reduce your discomfort.
- Depending on the type of anesthesia used, you may be completely asleep during the procedure. If awake, you may be asked to take slow, deep breaths while the tube is being inserted. This helps to relax your abdominal muscles and decrease the discomfort. You may also be asked to change your position to help the tube pass through.
- Air may be injected into your bowel. This may make it easier to see the inside surfaces. A water jet may also be used to clean the lining of your colon. A suction device may be used to remove any liquid stool.
- The health care provider will check your colon and may take photos. If a polyp is seen, it may be taken out. Or it may be left in the colon until a future procedure is performed.
- After the procedure is over, the tube will be taken out.
What If There Are Abnormalities Detected During Colonoscopy?
If an abnormal area needs to be better evaluated, a biopsy forceps can be passed through a channel in the colonoscope and a biopsy (a sample of the tissue) can be obtained. The biopsy is submitted to the pathology laboratory for examination under a microscope by a pathologist. If the infection is suspected, a biopsy may be obtained for culturing of bacteria (and occasionally viruses or fungus) or examination under the microscope for parasites.
If colonoscopy is performed because of bleeding, the site of bleeding can be identified, samples of tissue obtained (if necessary), and the bleeding controlled by several means. Should there be polyps, (benign growths that can become cancerous) they almost always can be removed through the colonoscope? Removal of these polyps is an important method of preventing colon and rectal cancer, although the great majority of polyps are benign and do not become cancerous. None of these additional procedures typically produces pain. Biopsies are taken for many reasons and do not necessarily mean that cancer is suspected.
What Happens After a Colonoscopy?
Most people who have a colonoscopy do not have bowel cancer. However, if referred, it is important that you have the procedure to be sure. If a colonoscopy reveals anything of concern (such as polyps, which may or may not be potentially cancerous), a sample will be taken to be tested by a pathologist. The person may also need to have imaging (such as abdominal scans) before deciding the best type of treatment for the bowel cancer.
Sometimes the first sign of bowel cancer is sudden blockage of the bowel. When this happens, bowel cancer is diagnosed by x-ray or computed tomography (CT) scan and usually requires an emergency operation.
After bowel cancer is diagnosed, doctors work out what stage it is at (how far it has spread). This may be done by checking findings of the scans. Tissue taken at the time of colonoscopy may be tested for genetic changes in the cancer cells, which can influence choice of treatment. The health professionals treating the individual will work closely together to get an accurate understanding of the cancer.
What Should I Expect When My Colonoscopy Is Done?
Patients will be kept in an observation area for an hour or two post-colonoscopy until the effects of medications that have been given wear off. If patients have been given sedatives before or during colonoscopy, they may not drive, even if they feel alert. Someone else must drive them home since their reflexes and judgment may be impaired for the rest of the day, making it unsafe to drive, operate machinery, or make important decisions.
Should patients have some cramping or bloating, this can be relieved quickly with the passage of gas, and they should be able to eat upon returning home. After the removal of polyps or certain other manipulations, the diet or activities of patients may be restricted for a brief period of time.
Prior to the patient’s departure from the coloscopic unit, the findings can be discussed with the patient. However, at times, a definitive diagnosis may have to wait for microscopic analysis of biopsy specimens, which usually takes a few days.