How are polyps diagnosed?
Polyps are diagnosed either by looking at the colon lining directly (colonoscopy) or by x-ray study (barium enema).
There are three types of colorectal endoscopy: (1) rigid sigmoidoscopy, (2) flexible sigmoidoscopy and (3) colonoscopy. Rigid sigmoidoscopy permits examination of the lower six to eight inches of the large intestine. In flexible sigmoidoscopy, the lower one-fourth to one-third of the colon is examined. Neither rigid nor flexible sigmoidoscopy requires medication and can be performed in the doctor’s office.
Colonoscopy uses a longer flexible instrument and usually permits inspection of the entire colon. Bowel preparation is required, and sedation is often used.
The colon can also be indirectly examined using the barium enema x-ray technique. This examination uses a barium solution to coat the colon lining. X-rays are taken, and unsuspected polyps are frequently found.
Although checking the stool for microscopic blood is an important test for colon and rectal disorders, a negative test does NOT rule out the presence of polyps. The discovery of one polyp necessitates a complete colon inspection, since at least 30 percent of these patients will have additional polyps.