Healthy Living

Colonoscopy: The Top 14 Questions

  • Generally, if you’re a healthy individual, you should have your first colonoscopy at 50 years old. African-Americans, meanwhile, even while healthy, should nonetheless have their first colonoscopy at 45 years of age.
  • Your colon will have to be emptied out for the colonoscopy to allow the doctor a clear, unobstructed view of all the parts of your colon.
  • A polyp found during a colonoscopy means a "positive" result. Polyps are not necessarily cancerous, although they can be precancerous or cancerous.

1 At what age should I have my first colonoscopy and how often should I have the succeeding ones?

Colonoscopy is a procedure that screens an individual for colon cancer. The age at which a person should go for screening usually depends on family history and race. Generally, if you’re a healthy individual, you should have your first colonoscopy at 50 years old. African-Americans, meanwhile, even while healthy, should nonetheless have their first colonoscopy at 45 years of age.

Individuals to whom high risk factors apply, such as having a first-degree relative with polyps or colon cancer or a history of inflammatory bowel disease, regardless of ethnicity need to undergo colonoscopy 10 years earlier than the age at which their first relative was diagnosed. For instance, if a first-degree relative is diagnosed with cancer of the colon at the age of 55, you should have your first colonoscopy at the age of 45.

For people at average risk of colon cancer, colonoscopies, with the addition of hemacult (for both men and women), must be done every 10 years. High-risk individuals should have colonoscopies every 3 to 5 years. Sigmoidoscopy and barium enema can be used as alternatives if colonoscopy is not available.

Although 50 years old is the baseline for colonoscopy, everyone should consult their doctor about the right age for them to get their first colonoscopy.

2 What does a positive occult blood test mean? What does a negative result mean?

The fecal occult blood test is a test used to check whether a stool sample has hidden (occult) blood, that is, blood not seen with the naked eye. Fecal occult blood is usually the result of intermittent bleeding from the upper or lower gastrointestinal pathway. This bleeding does not cause color changes in the blood. Although not all colon cancers or polyps bleed, occult blood in the stool could indicate polyps in the colon, or rectum or colon cancer.

This test is recommended as a method to screen for colon cancer. A positive result for a fecal occult blood test indicates that the stool sample has traces of blood. Additional tests such as a colonoscopy are needed to know where the bleeding is coming from. 

3 The colonoscopy prep: How long will the diarrhea last?

Your colon will have to be emptied out for the colonoscopy to allow the doctor a clear, unobstructed view of all the parts of your colon. To do this, the doctor will put you on a regimen that involves following a special diet, drinking only clear liquids, perhaps having an enema, and taking a bowel prep, which will trigger diarrhea to clean out your bowel. 
You will experience multiple bowel movements during your bowel prep. Expect to spend a lot of time in the washroom once you have begun. Diarrhea usually starts a few minutes to three hours after taking the bowel prep.

Most people experience abdominal discomfort and bloating, so you should not be alarmed by these as they are normal side effects of the prep. Nausea is also normal for many people, but if you experience severe nausea, your doctor will likely advise you to take an hour-long break before taking the rest of the bowel prep.

The diarrhea will last for about 16 hours. Doctors may also have you use laxatives and include an enema to fully flush out the colon. Colonoscopy prep is finished once the stool is liquid, clear, and light yellow, just like urine. Continue taking the prep mixture as instructed even if your stool becomes clear prior to the completion of the prep.

4 How can I tell if my colon is cleaned out?

Once the stool that comes out is almost clear or light in color, the colon is clean enough for a colonoscopy. If the stool is still dark-colored and mixed with solid materials, then more laxatives are needed.

A clean colon is needed because this will allow the doctor to examine the entire colon as well as remove, treat, or take biopsy samples of small polyps. Areas of the colon that are not cleaned out completely may cause the doctor to miss polyps or pre-cancerous tumors in those areas. Methane gas may also be present in the colon if a large portion of the colon is not clean. This is dangerous as electricity is used when treating polyps.

5 What if the colonoscopy prep doesn’t work?

The response to the colonoscopy prep differs from person to person.  If it has been more than three hours and the diarrhea has not begun, the prep is not working well. Drink more fluids, and if the prep still has not started working, take the second dose of the bowel prep, then keep drinking fluids. If the prep still has not begun to work after four hours, call your doctor for further instructions.

6 How long before the colonoscopy prep starts working?

Since everyone is different, the duration of colonoscopy prep is also different for every person. Some people begin having diarrhea within minutes, while others experience the response after an hour or more. For people who are less sensitive to laxatives, it could take several hours before the diarrhea starts. To be able to clean their colon, additional laxative may be needed.

7 What do I do if I throw up during colonoscopy prep?

If you start vomiting after taking the colonoscopy prep, wait one to two hours for your stomach to settle. Then, start drinking the bowel prep solution slowly with a longer time interval between gulps. It may take you longer to finish the solution, but slowing down can help prevent vomiting until the rest of the solution is finished.

8 How long before the colonoscopy prep does one have to stop eating?

You are advised to not eat solid food the day before your exam, and only clear liquids such as water, broth, tea, carbonated beverages, and coffee without cream or milk are allowed. Any red-colored liquid must be avoided as it might be mistaken for blood during the procedure. Patients will usually not be able to drink or eat anything past midnight prior to the colonoscopy.

9 What is the Miralax colonoscopy prep?

Miralax is a laxative solution that helps increase the amount of water in the intestines, thus triggering bowel movements. It is used to manage irregular bowel movements as well as occasional constipation. Miralax is often used for colonoscopy prep and consumed a day before the colonoscopy.

Miralax is mixed with a clear liquid such as Gatorade and must be fully dissolved before you drink it. Depending on the doctor’s advice, the solution can be consumed all at once or be drunk half and half. Also, prior to drinking the Miralax solution, you should take 4 tablets of Dulcolax.

10 Can one drive home after a colonoscopy?

You are not allowed to drive after a colonoscopy because you will be sedated during the procedure. Thus, you will probably not be able to efficiently and accurately make decisions soon after it. It can take an entire day before all the effects of the sedative wear off.

You should arrange for someone to drive you home after the procedure. You may take public transportation only if you have a companion.

11 When will I get the results from my colonoscopy?

After having undergone their colonoscopy, some patients receive the early results of the procedure. The doctor who performed the procedure will usually be the one to discuss the results. Any samples or biopsies taken are sent to the laboratory for further study, and the results will be sent to your doctor in a week's time. Once your doctor has received the results, he will call you to discuss them. Call your doctor if you don’t hear from him within two weeks.

12 What are the risks and possible side effects of colonoscopy?

Colonoscopy is a medical procedure that imposes risks just like other procedures. These risks as well as possible side effects are explained by the doctor to the patient before the procedure.

The most frequent side effects of colonoscopy are abdominal swelling and cramps. The swelling is due to the air that was used to inflate the intestine during the procedure. The symptom usually resolves on its own, as the air is expelled immediately after the colonoscopy.

A colonoscopy also carries the risk of damage to the intestinal wall, and perforation, bleeding, and possibly infection may occur in unfortunate cases. Fortunately, these are rare. Other risks include bleeding from the anus if biopsy is done along with the colonoscopy as well as adverse reactions to the anesthesia during the procedure.

If the patient experiences abdominal pain that gets worse, runs a fever, and passes a large amount of blood from the anus within 48 hours after the colonoscopy, the doctor must be consulted immediately.

13 What is a virtual colonoscopy?

Virtual colonoscopy is a type of procedure that can identify abnormalities such as bleeding, diverticulitis, and signs of colorectal cancer in the colon and rectum. It is also used to locate growths of tissue and polyps, which could be precancerous, in the colon as well as in the rectum.

Virtual colonoscopy uses a CT scan to create images of the large intestine. In some cases, MRI is also used. After the scan, images of the colon and rectum are combined by a computer to produce two- or three-dimensional views.

The difference between virtual colonoscopy and conventional colonoscopy is that the former uses imaging scans instead of the colonoscope, the instrument used for taking images and video during conventional colonoscopy.

Prior to a virtual colonoscopy, the bowel will also need to be emptied as with a conventional colonoscopy, thus the same need for bowel prep. The procedure is done on an outpatient basis and usually takes only 10 to 15 minutes. Unlike in conventional colonoscopy, patients who undergo virtual colonoscopy are not sedated.

Some of the advantages of virtual colonoscopy are:

  • Faster procedure compared to conventional colonoscopy
  • More comfortable than conventional colonoscopy
  • Does not require the use of sedatives
  • Less risk of injury to the intestinal walls
  • Patients can resume normal activities immediately after the procedure
  • Allows the doctor to assess the large intestine if it is constricted by swelling or an abnormal growth 

14 What happens if they find a polyp during the colonoscopy? How many polyps are normal?

A polyp found during a colonoscopy means a "positive" result. Polyps are not necessarily cancerous, although they can be precancerous or cancerous. Polyps found during the procedure will be removed and sent to the laboratory for further evaluation. Removal of all the polyps from the colon and rectum is usually recommended because of the possibility of these polyps being cancerous. After the polyps are examined in a laboratory, the result will be sent to the doctor. The doctor will then know whether the polyps that were taken were noncancerous, precancerous, or cancerous. A more thorough screening might be needed depending on the number and size of the polyps.

If the colonoscopy revealed one or two polyps with a diameter of less than 1 cm, a repeat colonoscopy within 5 to 10 years is recommended. However, more polyps or larger ones as well as polyps with certain cell characteristics might call for another colonoscopy after 3 to 5 years. If the polyps that were found were cancerous, a follow-up is needed within three to six months.

There is no exact number of polyps that is considered normal. Polyps are common and occur in thirty to fifty percent of adults. There are polyps that aren't and won't become cancerous, but there are also polyps that could or will. Polyp size is of greater concern than number because a polyp that has a diameter of greater than 1 cm could be cancerous.