Is A Flexible Sigmoidoscopy Painful?

What is flexible sigmoidoscopy?

A flexible sigmoidoscopy is a procedure using an endoscope camera and tools to examine and/or biopsy the lower part of the colon.
A flexible sigmoidoscopy is a procedure using an endoscope camera and tools to examine and/or biopsy the lower part of the colon.

Flexible sigmoidoscopy is a diagnostic procedure to examine the walls of the rectum and the lowermost part of the colon (sigmoid). Sigmoidoscopy is performed with a 60 cm-long flexible tube (sigmoidoscope) with a light and a miniature camera that transmits images of the rectum and sigmoid colon.

Alternatives to sigmoidoscopy in evaluating the status of the colon and rectum

What is the difference between a sigmoidoscopy and colonoscopy?

Both colonoscopy and sigmoidoscopy are screening tests performed with a flexible, lighted tube with a camera. A colonoscopy is examination of the entire colon, while a sigmoidoscopy scopes only the sigmoid colon and rectum.

What is the purpose of a flexible sigmoidoscopy?

A flexible sigmoidoscopy is performed to assess the health of the lower colon and rectum. A sigmoidoscopy may be performed 

Flexible sigmoidoscopy may not be performed in the following situations:

  • Bowel perforation
  • Acute diverticulitis -- inflammation of pouches that may form in the colon
  • Active peritonitis -- inflammation of the membrane covering the abdomen
  • Severe colitis -- inflammation of the colon
  • Cardiac or pulmonary diseases

What can the flexible sigmoidoscopy detect?

Flexible sigmoidoscopy can detect abnormalities in the rectum and sigmoid colon such as

  • Ulcers
  • Polyps
  • Abnormal cells
  • Tumors and cancer

Do you need sedation for a flexible sigmoidoscopy?

Sedation is not usually required for flexible sigmoidoscopy. It is a minimally invasive procedure that typically takes about 10 to 20 minutes. Some patients might require a calming medication.

How is a flexible sigmoidoscopy performed?

A gastroenterologist usually performs flexible sigmoidoscopy as an outpatient procedure.


A sigmoidoscopy does not usually need as much colon preparation as a colonoscopy. The patient must, however, ensure that the colon and rectum are completely clear of any gastric content so that there is no obstruction in viewing the rectum and sigmoid. The patient may need to

  • Go on a clear liquid diet for one to three days as instructed by the doctor.
  • Avoid red and purple foods like beets, which might look like bleeding.
  • Take a laxative in case of constipation.
  • Avoid eating or drinking anything but water from the night before the procedure.
  • Check with the doctor before taking any medications.
  • Inform the doctor of pre-existing conditions, diseases or allergies.
  • Have an enema before the procedure.


  • The patient lies on their side with knees drawn to their chest.
  • The doctor inserts the lubricated sigmoidoscope through the anus and guides it slowly through the rectum and sigmoid colon while checking the images in the monitor for abnormalities.
  • The doctor may inflate the colon with air to get a better view.
  • The doctor will remove polyps if found, extract tissue for a biopsy, and stop any bleeding.
  • The doctor then gently withdraws the tube.
  • The patient should be able to leave soon after the procedure.
  • The results of the sigmoidoscopy helps the doctor decide on future course of treatment.


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Is a flexible sigmoidoscopy painful?

A flexible sigmoidoscopy is generally not painful, though may be mildly uncomfortable. There might be a slight pinch if the doctor removes tissue for biopsy. Most people will be able to resume normal diet and activities immediately after the procedure.

What are the risks and complications of a flexible sigmoidoscopy?

A flexible sigmoidoscopy is a relatively safe procedure with rarely any complications. The side effects, which usually resolve in a short while, may include

Possible complications include

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