Flexible Sigmoidoscopy

A flexible sigmoidoscopy is a test your healthcare provider may use to examine your rectum and the lower third of your large intestine (colon). This includes your sigmoid colon and descending colon.

During the test, your provider uses a thin, flexible tube with a light and camera on the end (a sigmoidoscope). The scope allows your provider to clearly see the lining of your colon. It sends images to a video monitor so your provider can look for growths, inflammation or signs of cancer.

Flexible sigmoidoscopy is shorter and examines less of your colon than a colonoscopy. Healthcare providers commonly use it to check on digestive symptoms and sometimes to screen for colon cancer.

When is a flexible sigmoidoscopy performed?

Your provider may do a flexible sigmoidoscopy to:

• Figure out the cause of rectal bleeding or blood in your poop
• Assess ongoing belly pain, constipation and diarrhea
• Look for inflammation in the lining of your colon (colitis)
• Check for and remove colon polyps
• Follow up on abnormal imaging tests
• Examine your colon after radiation treatment to your pelvis
• Screen for colorectal cancer

How do I prepare for the test?

Proper preparation helps your healthcare provider clearly see your colon lining. You’ll need to prep your bowels. And you may need to adjust your medications.

Bowel prep

To prepare for a sigmoidoscopy, you’ll need to clean out the lower part of your colon. Preparations may involve:

• A clear liquid diet for part of the day before the test
• A laxative
• One or two enemas shortly before the procedure

Follow your provider’s instructions carefully. Call them if you have questions about how to prepare.

Medications

Tell your provider about all medications you take. You may need to:

• Stop taking iron supplements one to two weeks before the test
• Adjust your use of blood thinners
• Change your diabetes medications

Most blood pressure, heart, lung and seizure medications are safe to continue.

What should I expect during the test?

A flexible sigmoidoscopy usually takes place in a clinic or endoscopy center. Before the test, a nurse will review your medical history. Your provider will explain the procedure and ask you to sign a consent form.

The procedure is short, and discomfort is usually mild. So, you usually won’t need sedation. Most people remain awake during the test.

During the test, you’ll lie on your left side with your knees bent. This is the standard sigmoidoscopy position. Your provider will:

1. Gently insert a lubricated sigmoidoscope through your anus and into your rectum.
2. Slowly advance the scope through your rectum and sigmoid colon.
3. Introduce air into your colon to inflate it slightly, which helps them see clearly.
4. Use the camera on the scope to project video images onto a monitor.
5. Take tissue samples (biopsies), remove polyps or treat any bleeding or open wounds.
6. Slowly remove the scope while examining the lining of your colon again.

You may feel mild cramping, pressure or the urge to pass gas. You won’t feel any pain, even if you’re getting a biopsy. That’s because the lining of your colon doesn’t sense pain.

A flexible sigmoidoscopy is fast. It typically takes five to 15 minutes.

What are the side effects and risks of this test?

Flexible sigmoidoscopy is generally safe. Serious complications are rare. Possible side effects of sigmoidoscopy include mild cramping, bloating and light bleeding.

Rare risks include:

• Perforation (a tear in your colon wall)
• Severe belly pain
• Bleeding (especially if your provider does biopsies or removes polyps)

Most bleeding is minor and stops on its own. Your provider can usually control the bleeding during the procedure.

What can I expect after the test?

Most people feel fine after a flexible sigmoidoscopy. You should be able to drive home immediately (if you didn’t get sedation). You can eat normally and go back to your usual activities. You may continue to pass gas for a short time as the air leaves your colon.

When should I know the results of the test?

Your provider may discuss early findings with you right after the test.

If they did a biopsy, results usually take several days. Your provider will tell you how and when you’ll get them.

What type of results do you get and what do they mean?

Results may show:

• Normal findings: No polyps, inflammation or signs of cancer
• Polyps: Growths in the lining of your colon
• Inflammation: May suggest conditions like colitis
• Sources of bleeding: Like hemorrhoids or irritated tissue
• Signs of cancer: Abnormal growths or masses that need further testing

Some polyps can develop into cancer over time. If your provider finds polyps or signs of cancer, they may recommend a colonoscopy to check the rest of your colon.

If the results are abnormal, what are the next steps?

It depends on what your provider found during the procedure.

Your provider may recommend:

• A colonoscopy
• Polyp removal
• More imaging
• Treatment for inflammation
• Referral to a specialist

Your provider will explain what your results mean and guide you through the next steps.

When should I call my healthcare provider?

Call your provider right away if you have:

• Severe belly pain (not just gas cramps)
• A firm or swollen belly
• Fever
• Vomiting
• Heavy rectal bleeding (more than a few tablespoons)

These symptoms are uncommon after this procedure. But they need immediate medical attention.

What’s the difference between a flexible sigmoidoscopy and a rigid sigmoidoscopy?

A flexible sigmoidoscopy uses a thin, bendable tube. It lets your provider examine your rectum and lower colon more comfortably and completely.

A rigid sigmoidoscopy uses a shorter, straight tube. It examines only your rectum. Providers use it less commonly today.

Flexible sigmoidoscopy provides a better view of your sigmoid colon. It’s the preferred method in most cases.