A colonoscopy is a procedure to look at the inside of the colon. The colon is the large intestine and the last part of the digestive system. The colon dries, processes, and eliminates the waste left after the small intestine has absorbed the nutrients in food. The colon is about 3 to 5 feet long. It travels from the lower right corner of the abdomen (where the small intestine ends) up to the liver, across the body to the spleen in the upper left corner, and then down to form the rectum and anus. The doctor will use an instrument called the colonoscope to perform a colonoscopy. It is a long (about 5 feet), thin (about 1 inch), a flexible fiberoptic camera that allows the doctor to visualize the entire colon.
Most people develop polyps after age 50, so the American College of Gastroenterology (the digestive specialists) recommends screening examinations every 10 years for early detection and removal of these cancer-causing growths after that age.
What Diseases and Conditions Can Colonoscopies Diagnose?
A doctor may order a colonoscopy to investigate many different diseases of the colon. Colonoscopy is best known for its use as a screening tool for the early detection of colorectal cancer. Colorectal cancer is the second leading cause of cancer deaths in the United States. Colon cancer develops from growths within the wall of the intestine such as polyps or tumors. These growths often take 5 to 10 years to develop and may not cause many symptoms. A person may not have any symptoms of colon cancer, but having a close relative with the disease increases the risk of the disease compared to the general public.
Colonoscopy is used to investigate other diseases of the colon, for example, to find the place and cause of bleeding as well as to check areas for irritation or sores in the colon. These colon problems can cause unexplained changes in bowel habits. Pain, bloody diarrhea, and weight loss can be caused by inflammation of the bowel, which may be the result of Crohn's disease or ulcerative colitis. These inflammatory digestive diseases tend to occur in young adults and, if undetected, can produce chronic symptoms and increase the risk of colon cancer. Colonoscopy is used when there is concern a disease of the colon may exist.
The doctor may recommend this test if other screening tests such as a manual rectal examination, a fecal occult blood test (a test that detects blood in the feces), or a barium enema (a test in which barium is used to make the colon visible on an X-ray) suggest that further information is needed to make a diagnosis. A colonoscopy may be required when symptoms of digestive disease or other warning signs are present, for example, rectal bleeding (which may appear as bright red, very dark, or black); pain in the lower abdomen; changes in bowel habits; non-dietary weight loss
A new test called Cologuard, a stool-based colorectal screening test that detects the presence of red blood cells and DNA mutations, may indicate the presence of certain kinds of abnormal growths that may be cancers such as colon cancer or precursors to cancer. If this test reveals the possibility of colon cancer, a colonoscopy may be necessary.
Only doctors who specialize in the study of digestive or rectal diseases, have special training in endoscopy and are certified to perform colonoscopy qualify to perform this procedure.
Most people develop polyps after age 50, so the American College of Gastroenterology (the digestive specialists) recommends screening examinations every 10 years for early detection and removal of these cancer-causing growths after that age.
As with any procedure, there are risks associated with a colonoscopy. Before obtaining your consent for the procedure, the doctor will tell you about the potential risks.
A colonoscopy can be performed in a hospital, clinic, or in a doctor's office, depending on the facility and situation. The patient will be given an appointment and a set of instructions to follow before the test is performed.
On the day of the colonoscopy, the patient may be asked to arrive early to prepare for the test itself, and to ask further questions. The patient will be asked the following questions. When did you last eat? What allergies do you have? Did you remember to take all your bowel preparation medication?
Once the patient has changed into an examination gown, vital signs (blood pressure, heart rate, respiration rate, and temperature) will be monitored and an intravenous line (IV) will be placed to sedate the patient, and provide pain medication during the test, if necessary. Although the patient will not be fully asleep during the procedure, these medications will produce a sleepy state (sedation) and make the test more comfortable.
The procedure will begin with the patient lying flat on the left side. The colonoscope, is lubricated to allow it to enter the anus. For a thorough investigation, air is required to gently open the folded colon. This may cause a temporary uncomfortable bloated sensation. When the doctor applies gentle pressure, the colonoscope moves further into the colon and is slowly advanced until the entire colon is seen.
The colonoscope has a tiny camera on the end of it, which is connected to a monitor. This allows the physician to see the colon through the tip of the instrument even when it is far inside the body. As the scope passes the course of the colon, the normal turns and contours of the colon may impede the passage of the scope. The patient may be asked to change positions for better visualization. It is common for fluid and gas to escape through the rectum and anus; this should be expected. The entire procedure can take from 30 minutes up to 1 hour. In addition to simply viewing the bowel wall, the colonoscope has special attachments that allow the doctor to collect tissue samples or biopsies, remove small growths, and stop bleeding with laser, heat, or medication.
You will go home later during the day after you have your colonoscopy. Colonoscopy usually is performed without checking into the hospital (as an outpatient procedure). You will be monitored and observed in the doctor's office until the side effects of the medications have worn before you can go home. The side effects of the medication may cause symptoms like nausea, bloating, and drowsiness, that may continue for some time after the procedure. You should make arrangements for someone to come and pick you up at the doctor's office and take you home because of these side effects. Recovery time after the procedure can vary. If there are no complications it can range from a few hours to a few days.
Your doctor will give you a follow-up appointment. The final results of the test are generally available at that appointment, although biopsy results may take some time. The doctor may give you specific instructions in regard to what symptoms to monitor, which ones are normal, and which are more serious. You also may receive information in regard to your diet after a colonoscopy.
Other tests can help a doctor detect diseases of the colon. Sometimes these tests can be done instead of a colonoscopy, but at other times they are performed in addition to a colonoscopy because each test can provide different types of information.
Your doctor will decide which of these tests is most appropriate for you.
Call a doctor if any unexpected symptoms occur, including:
If there are additional concerns, call the doctor's office for advice and evaluation.
Minor symptoms, such as bloating, are common after this procedure. More serious symptoms should prompt the patient to seek urgent medical attention. Call your physician and go directly to the emergency department if the patient experiences any of the following:
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Colon cancer, also referred to as colorectal cancer, occurs when cancer cells form in lining of the colon or rectum. In the early stages of colon cancer there often are no symptoms. As the cancer progresses through the large intestine, symptoms and signs may begin appear, for example:
