A sigmoidoscopy is a procedure that closely examines the last third of the descending colon. This is typically done if an entire colonoscopy is unnecessary. It is short and painless and involves inserting a flexible tube called a sigmoidoscope into the anus. The device has a light and camera attached at the end, which enables a full view of the descending colon (just under the last 2 feet of the large intestine). If necessary, tissue samples can be taken through the scope during the procedure. Symptoms that might warrant a sigmoidoscopy are:
- Rectal bleeding
- Abdominal pain
- Changes in normal bowel movements
- Sudden unexplained weight loss
- A family history of colorectal cancer
A sigmoidoscopy is very similar to a colonoscopy. One or more enemas will be likely be needed about 2 hours before the procedure. A liquid diet may also be necessary for several days prior to ensure that the colon is empty. Some approved foods and liquids include water, sports drinks with electrolytes, plain tea or coffee, clear broths, and gelatin.