What Is a Sigmoidoscopy?

Why Is a Sigmoidoscopy Done?

A gastroenterologist may request a sigmoidoscopy as part of the protocol for colon cancer screening in people of average risk. Alternatively, they may use a sigmoidoscopy to as a diagnostic test to identify a problem or therapeutic test, such as to remove polyps. The symptoms that may trigger a sigmoidoscopy request for some people include:

• Rectal bleeding or bloody stool (poop)
• Changes in your stool, such as diarrhea
• Abdominal pain
• Unintentional weight loss

• People ages 45 or older
• Black people
• People with a genetic disorder that increases the risk of colorectal cancer, such as Lynch syndrome
• Those with obesity
• Individuals who smoke cigarettes or drink alcohol

In most practices, doctors will recommend a full colonoscopy for screening. However, flexible sigmoidoscopy still remains an option as well. However, certain factors increase an individual’s risk for colorectal cancer and would make a full colonoscopy the preferred method. These include:

• Those with a family or personal history of colorectal cancer
• Individuals with a personal history of polyps, ovarian cancer, or colorectal cancer
• People with IBD, such as those with UC or Crohn’s disease

How Is a Sigmoidoscopy Performed?

How Do I Prepare for Sigmoidoscopy?

• Plain water
• Fat-free broth
• Pale, filtered juices, like apple or white grape juice
• Gelatins or sports drinks flavored with lemon, lime, or orange
• Tea or coffee without cream or milk

What Should I Expect During a Sigmoidoscopy?

Your doctor will then begin the procedure, inserting a sigmoidoscope through your anus into your rectum and left side of your colon. “The procedure itself is fairly quick,” says Benjamin Click, MD, a gastroenterologist at the UCHealth Digestive Center in Aurora, Colorado. But it may take longer “if there is some therapy or intervention that’s needed as part of the procedure,” such as the need to take additional biopsies or look more closely at a specific area of your colon.

What Are the Potential Risks Associated With a Sigmoidoscopy?

• Reactions to sedation
• Bowel perforation, or a hole in the wall of the intestine, which is rare
• Continued bleeding, which is rare
• Peritonitis, or inflammation of the lining of the abdomen, which is very rare

What Type of Care Is Needed Following a Sigmoidoscopy?

No immediate lifestyle changes or diet changes will be necessary. However, if you receive sedation, you won’t be able to drive right away and will need to have someone accompany you home, Click says. You’ll also need a few hours off of work. But if you decide against sedation, you can leave on your own and go back to your normal activities right away.

What Are the Possible Complications and Side Effects of a Sigmoidoscopy?

What’s Next?

The next steps after receiving a flexible sigmoidoscopy depend on your reason for having it.

Sigmoidoscopy vs. Colonoscopy: What’s the Difference?

Because it only involves the last few segments of your colon, a sigmoidoscopy doesn’t require as much preparation as a colonoscopy. “Unlike a colonoscopy, one typically does not have to consume an oral lavage solution to entirely clean out the colon,” Click says. Instead, he says, most people only require one or two enemas several hours before their sigmoidoscopy to flush out stool from the area.

Another difference is that while sedation is generally recommended for a colonoscopy, doctors consider it optional for a sigmoidoscopy. “A lot of the unpleasantness in a colonoscopy is from trying to get to the end of the colon,” says Ashwin Ananthakrishnan, MBBS, a gastroenterologist at Massachusetts General Hospital in Boston.

Of course, the more limited nature of a sigmoidoscopy also carries certain disadvantages. “It’s not able to look at inflammation on the right side of the colon if you’re looking for inflammation for disease surveillance, look for polyps elsewhere if you’re receiving sigmoidoscopy as a screening test, or look into your small intestine,” says Dr. Ananthakrishnan. That means not everyone will be an ideal candidate for a sigmoidoscopy as a substitute for a colonoscopy.

The Takeaway

• A sigmoidoscopy is essentially an abridged colonoscopy that only examines the bottom third of the colon. An endoscopist inserts a flexible, lighted tube with a camera attached to produce images of the rectum, sigmoid colon, and descending colon.
• This procedure can be part of a colon cancer screening and often plays a crucial role in diagnosis and monitoring of certain digestive conditions like inflammatory bowel disease.
• You’ll need to eat a special diet ahead of the procedure, as well as using a bowel prep kit to clean the area with enemas before examination.
• A sigmoidoscopy typically takes only around 15 minutes, and sedation is usually not necessary. However, if you opt for sedation, you won’t be able to drive home immediately after the procedure.