Sigmoidoscopy: Definition, Indications, Preparation, Procedure, and Treatments That Can Be Performed During a Sigmoidoscopy

It allows the lower portion of the colon to be examined with the help of an endoscope or thin tube.

It can help diagnose some intestinal issues that can cause symptoms such as constipation or diarrhea, and abdominal pain.

Abnormal growths can also be detected.

A flexible sigmoidoscopy is an exam of the lower (distal) part of the gastrointestinal tract, called the colon or large intestine.

Indications for a sigmoidoscopy

The most common reasons for flexible sigmoidoscopy are as follows:

  • A test to detect colon polyps or colon cancer in people over fifty. This recommendation has been superseded by colonoscopy as the primary screening tool.
  • Blood in the stool or rectal bleeding is believed to be from the lower colon or anorectal area.
  • Persistent diarrhea
  • After radiation treatment to the pelvis, a patient has lower gastrointestinal symptoms.
  • For the medical treatment of colitis (inflammation of the colon).

Preparation for the procedure

The lower part of the colon must be cleaned to allow the endoscopist to see the colon’s inner lining.

Specific instructions will be provided, although preparation generally involves consuming a clear liquid diet, laxatives, and enemas shortly before the exam.


Most medications can be continued as usual. However, there are some medications whose use should be discussed with your doctor before the exam.

Some medications, such as aspirin products and iron preparations, must be stopped a week or two before the test.

Aspirin increases the risk of bleeding after the test, while iron coats the colon, making it difficult to see the lining.

People taking a blood-thinning medication such as warfarin (Coumadin) or Pradaxa should consult with their doctor about the need to temporarily stop taking this medication.

Most medications for high blood pressure, heart disease, lung disease, and seizure disorders are safe during sigmoidoscopy and can be taken on the exam day.

Medications for diabetes may need to be tapered before the test.

Sigmoidoscopy procedure

Flexible sigmoidoscopy generally takes between five and fifteen minutes.

It is done while the patient is awake and lies on their left side with their legs bent against their chest.

The sigmoidoscope, which is about the size of a finger, is inserted into the anus and advanced through the rectum, sigmoid colon, and descending colon.

The sigmoidoscope has a lens and a light source that allows the endoscopist to view the intestine through the scope or on a monitor.

The endoscope allows the endoscopist to take biopsies (small pieces of tissue) and insert or remove fluid or air.

Biopsies do not hurt because the colon’s lining does not feel pain. However, some patients will feel cramping when air is introduced through the scope and when the area is passed through colon segments.

Air is needed to allow the endoscopist to advance the scope and view the colon’s lining. However, there are risks to a flexible sigmoidoscopy, as with any procedure.

Bleeding and tearing (perforation) of the lining of the large intestine are very rare.

Bleeding can occur from biopsies or removal of polyps, but this is usually minimal and stops quickly or can be controlled.

The scope can cause a tear or hole in the tissue being examined.

In rare cases, blood transfusions or emergency surgery may be needed.

After flexible sigmoidoscopy, the following problems should be reported immediately:

  • Severe abdominal pain (not just gas cramps).
  • A persistent or increasingly firm distended abdomen.
  • Vomiting
  • Fever.
  • Heavy bleeding

Although patients worry about the discomfort of the exam, most people tolerate it very well and feel fine afterward.

Treatments that can be done during a sigmoidoscopy

  1. Biopsy: If the doctor thinks that an area of ​​the lining needs to be examined more closely, he will take a small portion (biopsy). This piece is sent to the laboratory for examination.
  2. Cauterization: If the doctor finds an area of ​​bleeding, it can be controlled by applying medicine through the endoscope directly to the size of ​​the bleeding. The doctor can also cauterize through the endoscope and seal the blood vessels with heat treatment.
  3. Polyps removal: If the doctor finds polyps in the colon lining, they can be removed. Polyps range in size from a small point to several inches.

Most polyps are not cancerous, but a doctor cannot tell a non-cancerous polyp by its appearance. For this reason, if the doctor removes a polyp, it is sent to the laboratory for further testing. Polyp removal is a meaningful way to prevent colon cancer.