What Is A Colonoscopy Procedure & Why Do You Need To Do It?

Colonoscopy is a procedure in which the entire large bowel can be visualized and evaluated with the help of a long flexible tube having light and tiny camera at one end. Since 1970, colonoscopy is commonly used in gastroenterology. The instrument used is called colonoscope. In this procedure a tube is inserted through the anus. It helps to detect polyps, diseases such as Crohn’s disease, ulcerative colitis, and most importantly colon cancer.

It also gives an opportunity for removal of polyp or a tissue biopsy from suspected cancerous lesion in colon. Physicians recommend screening colonoscopy for colon cancer in anyone over the age of 50 years.

So let us know how the colonoscopy procedure is performed and its indication in detail.

How Does A Colonoscopy Procedure Work?

Colonoscopy can be performed as an outpatient procedure. This means patient does not have to stay in the hospital. It is mandatory that colon must be clean for proper evaluation and examination purpose. Various agents are used to clean the bowel so that the physician can clearly view the bowel. Polyethylene glycol (PEG) with electrolytes is generally used for this purpose.

Patient may sometime have skin irritation in and around anus due to passage of liquid stools.

However, this can be alleviated by applying Vaseline around the anus. Patient can wipe the anus with disposable wet wipes. Patient must inform the physician if he is taking any medicine before the procedure is performed, especially if the patient is taking blood thinners or iron supplements.

  • Once the patient is completely prepared, he will have change into hospital gown.
  • Most people are sedated before the procedure starts. Patient will feel relaxed and slightly drowsy.
  • Patient is then told to lie on left side with right leg from knees drawn towards chest.
  • Colonoscope is passed after applying some lubricant jelly for smooth passage into the anus and in the rectum and then to the colon.
  • During this procedure some amount of gas is passed so that the colon and its lining are well visualized.
  • Patient may have cramping sensation for some time due to the gas but it reduces after some time.
  • The physician can view the colon and the suspected area of colon with the help of camera in the scope.
  • If some pathology is found such as a polyp or a suspected cancerous lesion, he may take small piece of biopsy material with colonoscope.
  • The whole procedure may take 40 minutes to 1 hour.

After colonoscopy patient will have to stay in the recovery room for one or two hours till the effect of sedative is over. Patient may then be allowed to go home with precautionary advice such as not to drive for a day or drink alcohol. Patient may take normal diet few hours after the procedure or as advised by the doctor. He will also be told when to start taking his usual medicines.

Why Do You Need To Get A Colonoscopy?

Colonoscopy is performed for two purpose; therapeutic and for diagnosis of a disease. It is a screening test often performed in people over the age of 50 for detecting colon cancer. It provides better view of colon as compared to other methods such as barium X-ray of colon. Most colon cancers begin as non cancerous polyps. Removing these polyps and examining them for cancer at an early stage has increased chance of complete recovery.

Here are some indications for colocnscopy;


  • Unexplained bleeding from rectum.
  • Polyp and colon cancer follow up.
  • Inflammatory bowel diseases such as Crohn’s disease and irritable bowel syndrome.
  • Unexplained change in bowel habit such as constipation and diarrhea.
  • Stricture in colon
  • Infectious colitis
  • Ischemic colitis.

Therapeutic indications:

  • For removing foreign body in the rectum and colon.
  • Resection of tumor in colon.
  • Removing polyps
  • Dilating stricture