Sigmoidoscopy Procedure
What It Is And What To Expect

A sigmoidoscopy procedure or exam is a type of endoscopy or camera test that examines the inside of your rectum and the left lower part of the large intestine or colon. There are two types of sigmoidoscopies: a flexible sigmoidoscopy and a rigid sigmoidoscopy. The difference is the tool your doctor selects to perform the procedure. This simple procedure saves lives. See what exactly it is, what to expect if you having one, how to prepare and risks and complications associated with sigmoidscopy.

Sigmoidoscopy procedure in progress.Sigmoidscopy procedure in progress.

The Lancet medical journal of April 2010, reports that a single sigmoidoscopy exam in adults between the ages of 55 and 64 years, and removal of any polyp seen, reduces the chances of developing cancer of the colon by up to a third and death from colon cancer by over 43%.

After a very extensive study in 170,432 eligible men and women in 14 different health facilities in the UK, the research concluded that " Flexible sigmoidoscopy is a safe and practical test and, when offered only once between ages 55 and 64 years, confers a substantial and longlasting benefit."

Why is this important? Colon cancer is the third most frequently diagnosed cancer in the world, with over 1 million new cases reported every year and over 600,000people dying from this type of cancer yearly.

66% of all cancer of the colon occurs in the rectum, sigmoid colon, descending colon and splenic flexure; areas of the large intestine accessible and covered during a routine sigmoidoscopy.

What that means is that a quick, relatively less painful and less invasive procedure like flexible sigmoidoscopy, compared with colonoscopy, has the potential to reach and identify over 2/3rd of all possible large bowel cancer.

What Is Sigmoidoscopy?

A sigmoidoscopy is a type of camera test or endoscopy that examines the inside of your rectum and the left lower part of your large intestine or colon, using an instrument called a sigmoidoscope.

A sigmoidoscope is a special, long, pen sized tube with a magnifying glass, telescope, camera and light source attached to its tip, with which you can see the inside of the lumen of the left side of the large intestine, from the rectum up to the part of the colon under your left rib cage called the splenic flexure.

Your primary care doctor usually performs a sigmoidoscopy. In some places, a specialist doctor, an endoscopist does it.

During a sigmoidoscopy, the doctor gently guides a tube with a camera on the end through your anus and up through the rectum and lower third of your large intestine. The doctor uses the special camera that is attached to the sigmoidoscope to examine and take pictures of the inside of your rectum and lower portion of the colon.

There are two types of sigmoidoscopies:

  • a flexible sigmoidoscopy and
  • a rigid sigmoidoscopy.

The difference is the tool your doctor selects to perform the procedure.

  • A flexible sigmoidoscope is a long and flexible tube that is approximately 70 centimeters in length and 1 centimeter in diameter.
  • The rigid sigmoidoscope is similar to the flexible sigmoidoscope, except much shorter and slightly wider. The rigid sigmoidoscope is only about 25 centimeters in length and 2.5 centimeters in diameter.

Doctors use the flexible sigmoidoscope more often, because the flexible sigmoidoscope allows the doctor to view more of the lower colon, and it is more comfortable for the patient.

Why Is Sigmoidoscopy Done?

There are several reasons why your doctor may order a sigmoidoscopy, or why a sigmoidoscopy is done on someone. It could be because of:

  • Changes in your bowel movements
  • Blood in your stool
  • If you have an unexplained low levels of iron in your blood
  • Bleeding from the rectum
  • Low abdominal pain that has not been diagnosed with the use of another type of test
  • If your doctor suspects that you have polyps
  • If you doctor thinks you have ulcers or inflammation in your lower large bowels
  • If you have inflammatory bowel disease like ulcerative colitis or Crohn's disease
  • If you have chronic diarrhea
  • If your doctor thinks you might have a tumor or colorectal cancer
  • If it is time for a routine colon cancer screening, which is recommended every five years, depending upon your medical history and your family medical history. Sometimes sigmoidoscopies are performed more frequently, because they can be done in your general internist’s office.

Often, doing a colonoscopy is more thorough and far reaching than having a sigmoidoscopy. Sigmoidoscopy however does not always require sedation, you do not really have to clear the bowel as much as is needed with colonoscopy and it is quicker to perform.

What Should I Expect During A Sigmoidoscopy?

Whether you are having a flexible or rigid sigmoidoscopy, the process is similar.

  • In both procedures, the doctor takes a lubricated, narrow, hollow, lighted tube (the sigmoidoscope) and passes it from the anus, through the rectum and lower portion of the colon. There will be some lubricant placed by your doctor around the anus, the opening to the rectum.
  • The tubes used to perform a sigmoidoscopy have a small fiberoptic video cameras at the tip that is traveling inside of your intestine, that allows your doctor to take still photographs or video pictures of the inside of your rectum and lower colon.
  • A doctor can examine much more of the colon with a flexible sigmoidoscope than with a rigid sigmoidoscope, because it is about 50 centimeters longer, and it is also more flexible and easier to guide around the curves in your intestines.

During a sigmoidoscopy, your doctor will also be able to take tissue samples, or biopsies. If you have growths in the colon, called polyps, they can be removed and microscopically examined for signs of malignancy.

The sigmoidoscopy takes 10 to 15 minutes, but can possibly last longer if the doctor removes tissue. Pain medication and sedation are not usually necessary.

How Should I Prepare For A Sigmoidoscopy Procedure?

Preparing for a sigmoidoscopy procedure is easy. Though details vary from one clinic or hospital to another, it is basically the same principle. Be sure to read through and follow the local instruction given to you by your attending physician. 

  • Before your sigmoidoscopy, you need to clean out the colon. You should follow a liquid diet for 1 to 2 days prior to the exam so the doctor can see the walls of the colon
  • You may be given a phosphate enema laxative about 30 to 60 minutes before the procedure to help you pass out and clean your lower colon even more
  • Sometimes your doctor will ask you to give yourself an enema with tap water the night before the test, to empty your intestines so the doctor can see the most of the interior of the large intestine. Stool in your colon can block the doctor’s view, so be certain to follow your doctor’s instructions carefully.
  • Your doctor will tell you how long you should abstain from eating, but you will be able to have clear liquids.
  • Sometimes you may have to make adjustments to your medications before the exam, so be sure to let your doctor know what medications you take, including insulin and aspirin.

Depending upon your age and your risk factors, your doctor might recommend a routine sigmoidoscopy procedure every three to five years. Your doctor will follow guidelines that are based upon evidence that has shown that there is a benefit in terms of mortality and morbidity, or prevention of death and disease, by having a sigmoidoscopy performed.

What Are Possible Risks Of A Sigmoidoscopy

Sigmoidoscopy procedure or exam is a relatively very safe test, especially in an experienced hand.

Very very rarely, there could be complications due to:

  • Perforation or tearing of the sigmoidoscopy through the wall of the colon, leading to internal bleeding
  • There could be bleeding and excessive blood loss, if a polyp were to be seen and cut or from perforation and then the bleeding was not stopped
  • Some people develop problems following sedation they suffer with prior breathing or heart problems
  • Infection. If there is perforation and fecal matter is introduced into the deeper tissue, you could develop internal infection and abscess formation.

It must be emphasized that any and all of these complications are very very rare.

After the sigmoidoscopy, call the doctor if you have:
•    Heavy rectal bleeding
•    Severe abdominal pain
•    Fever or feel unwell in any way.

What Are The Possible Results Following A Sigmoidoscopy?

During a sigmoidoscopy, the doctor will evaluate the lining of the colon. If the lining of your colon appears smooth and pink with regular folds, your colon is normal.

Abnormal results include:

  • Hemorrhoids
  • Polyps
  • Tumors
  • Ulcers
  • Diverticulosis
  • Inflammation
  • Infection

Depending on the results, you may need additional testing such as a colonoscopy or further examination through another sigmoidoscopy.

Sigmoidoscopy Stories & Interpretations: Post Yours Here!

Do you have a great sigmoidoscopy story? Or are you due to have a sigmoidoscopy soon and looking for answers to a specific question relating to the sigmoidoscopy procedure? Or perhaps just had this test and looking for help with some symptoms or interpretation of your result? Post your concerns or comments here. We would really love to hear from you!

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