April 21, 2024

Colonoscopy: What are Some of the Contraindications?

A colonoscopy is a procedure that is done to look inside the large intestine or colon. The procedure uses a device called a colonoscope which will be inserted into the rectum. A colonoscopy is done by a gastroenterologist.

The procedure is also done to check for colon cancer. Colonoscopy is also done to evaluate certain conditions that relate to the colon including rectal bleeding, abdominal pain, and any change in bowel habits.

After the colonoscope has been inserted into the patient’s rectum, the tube will be threaded through the colon. This is done so images can be viewed on the monitor. This makes it easy as well to see any abnormalities or tissue growths.

Some of the abnormalities that will be checked include tissue growths (polyps), ulcers (sores), bleeding, and inflammation. Aside from checking for abnormalities, colonoscopy is also used to treat specific issues.

For instance, tiny instruments can be inserted through the scope to remove polyps. Biopsies or tissue samples may also be obtained during the procedure.

Colonoscopy Contraindications

Below are some of the contraindications of the procedure:

  • Severe toxic megacolon
  • Fulminant colitis
  • Recent heart attack
  • Peritonitis
  • Hemodynamic instability
  • Suspected or known colon perforation
  • Bowel injury and repair
  • Colonic anastomosis

Potential Colonoscopy Risks

Below are some of the potential risks of the procedure:

Side effects of the medication

Some people have an allergic reaction to the sedative or pain medications used. Some of the most common side effects include vomiting or nausea. However, this is very rare. You should raise up any allergies you may have to the doctor before the procedure.


Bleeding usually only occurs in 1 of 1000 colonoscopy procedures. Bleeding is more likely when removal of polyp is done.

Colon Perforation

Colon perforation is very rare. However, it can still happen. Colon perforation occurs when air is injected into the colon during colonoscopy so visualization is improved. Perforation can also occur when the bowel is punctured by an instrument.

Certain factors can also increase one’s risk for colon perforation. Some of the key factors include having Crohn’s disease, history for abdominal pain, being in intensive care at the time of the procedure, and age.


While infection is a risk of all surgeries, infections rarely occur during and after colonoscopy.

Postpolypectomy Syndrome

Just like bleeding, this usually only occurs in 1 out of 1000 colonoscopies. Postpolypectomy syndrome is also likely to occur when burning or cautery (electrocoagulation) is done to stop the bleeding at the polyp’s base when it is removed. Symptoms of this syndrome can include abdominal pain and fever.

How to Prepare for the Procedure

As soon as the procedure is scheduled, you will be given different preparatory instructions including:

  • You need to arrange for someone drive you home after colonoscopy since you may still be feeling drowsy after the procedure
  • You need to start a low-fiber diet a few days before the procedure
  • You can only drink clear liquids the day prior to colonoscopy as liquids with blue, purple, or red dyes may stain the colon and affect the images produced
  • You need to stop taking certain medications such as anticoagulants and nonsteroidal anti-inflammatory drugs at least for a brief period before your colonoscopy

To ensure the colon is cleaned out thoroughly, you will be asked to go through bowel preparation. Typically, bowel preparation involves the use of a liquid laxative known as polyethylene glycol (Golytely).

While there are various types of bowel preparations, they can all cause hours of watery diarrhea. That said, you need to make sure you have fast and easy access to the restroom during that time.

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