Patients presenting with rectal bleeding, bowel cancer or Inflammatory bowel disease (IBD), may require a flexible sigmoidoscopy. Flexible sigmoidoscopy is a procedure in which a flexible, narrow tube with a light and tiny camera on one end, called a sigmoidoscope or scope, is used to look inside your rectum and lower colon, also called the sigmoid colon and descending colon. Flexible sigmoidoscopy can show irritated or swollen tissue, ulcers, polyps, and cancer.
A flexible sigmoidoscopy can help a doctor find the cause of unexplained symptoms, such as:
- bleeding from your anus
- changes in your bowel activity such as diarrhea
- pain in your abdomen
- unexplained weight loss
A flexible sigmoidoscopy may also be used as a screening tool for colon polyps and colon and rectal cancer. Screening may find diseases at an early stage, when a doctor has a better chance of curing the disease.
Screening for colon and rectal cancer
Your consultant may recommend screening for colon and rectal cancer if you don’t have health problems or other factors that make you more likely to develop colon cancer.
Factors that make you more likely to develop colorectal cancer include
- someone in your family has had polyps or cancer of the colon or rectum
- a personal history of inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease
- other factors, such as if you weigh too much or smoke cigarettes
If you are more likely to develop colorectal cancer, your consultant may recommend screening at a younger age, and you may need to be tested more often.
Most consultants will recommend colonoscopy to screen for colon cancer because colonoscopy shows the entire colon and can remove colon polyps. However, preparing for and performing a flexible sigmoidoscopy may take less time and you may not need anesthesia .
If abnormal tissue or one or more polyps is found during a flexible sigmoidoscopy, you may have a colonoscopy to examine the rest of your colon.
How do I prepare for a flexible sigmoidoscopy?
To prepare for a flexible sigmoidoscopy, your consultant will discuss things like changes to your diet, and cleaning out your bowel.
Talk with your consultant
You should talk with your consultant about any medical conditions you have and all prescribed and over-the-counter medicines, vitamins, and supplements you take, including:
- arthritis medicines
- aspirin or medicines that contain aspirin
- blood thinners
- diabetes medicines
- nonsteroidal anti-inflammatory drugs, such as ibuprofen or naproxen
- vitamins that contain iron or iron supplements
Change your diet and clean out your bowel
You will be given bowel preparation instructions to follow at home before the procedure. A complete bowel prep lets you pass stool that is clear and liquid. Stool inside your colon can prevent your consultant from clearly seeing the lining of your intestine.
You may need to follow a clear liquid diet the day before the procedure. The instructions will provide specific direction about when to start and stop the clear liquid diet. In most cases, you may drink or eat the following:
- fat-free bouillon or broth
- gelatin in flavors such as lemon, lime, or orange
- plain coffee or tea, without cream or milk
- sports drinks in flavors such as lemon, lime, or orange
- strained fruit juice, such as apple or white grape—doctors recommend avoiding orange juice and red or purple liquids.
Your consultant will tell you how long before the procedure you should have nothing by mouth. The bowel preparation can sometimes cause diarrhea as different bowel preps may contain different combinations of laxatives. Some patients may need to drink a large amount of liquid laxative over a scheduled amount of time – usually the night before the procedure.
How is a flexible sigmoidoscopy performed?
For the procedure, you will be asked to lie on the bed while your consultant inserts a sigmoidoscope into your anus and slowly guides it through your rectum and into your sigmoid colon. The scope pumps air into your large intestine to give the doctor a better view. The camera sends a video image of your intestinal lining to a monitor, allowing the doctor to examine the tissues lining your sigmoid colon and rectum. Your consultant may ask you to move several times to adjust the scope for better viewing. Once the scope has reached your transverse colon, the doctor slowly withdraws it and examines the lining of your sigmoid colon again.
During the procedure, your consultant may remove polyps and send them to a lab for testing. Colon polyps are common in adults and are harmless in most cases. However, most colon cancer begins as a polyp, so removing polyps early is an effective way to prevent cancer.
If polyps or other abnormal tissue is found during a flexible sigmoidoscopy, your consultant may suggest you return for a colonoscopy.
What should I expect after a flexible sigmoidoscopy?
After a flexible sigmoidoscopy, you can expect the following:
- You may have cramping in your abdomen or bloating during the first hour after the procedure.
- You should be able to resume regular activities immediately after the procedure.
- You can return to a normal diet.
We will provide written instructions on how to take care of yourself after the procedure and will review them with you. You should read and follow all instructions.
If your consultant removed polyps or performed a biopsy, you may have light bleeding from your anus. This bleeding is normal. Some results from a flexible sigmoidoscopy are available right after the procedure, and your consultant will share these results with you. A pathologist will examine the biopsy tissue. Biopsy results take a few days or longer to come back.
What are the risks of a flexible sigmoidoscopy?
The risks of a flexible sigmoidoscopy include:
- perforation of the colon
- severe pain in your abdomen
- death, although this risk is extremely rare
Bleeding and perforation are the most common complications from flexible sigmoidoscopy. Most cases of bleeding occur in patients who have polyps removed. Your consultant can treat bleeding that occurs during the flexible sigmoidoscopy immediately. However, you may have delayed bleeding up to two weeks after the procedure and your consultant may need to treat perforation with surgery.