Rectal Bleeding (cont.)
Anoscopy
An anoscope is a
three-inch long, tapering, metal or clear plastic, hollow tube approximately one
inch in diameter at its wider end. The anoscope is lubricated, and the tapered
end is inserted into the anus, through the anal canal, and into the rectum. As
the anoscope is withdrawn, the area where internal hemorrhoids and anal fissures
are found is well seen. Straining by the patient, as if they are having a bowel
movement, may make hemorrhoids more prominent.
Whether or not hemorrhoids and
anal fissures are found, if there has been rectal bleeding, the colon above the
rectum needs to be examined to exclude other important causes of bleeding.
Examination above the rectum can be accomplished by either flexible
sigmoidoscopy or colonoscopy, procedures that allow the doctor to examine
approximately one-third or the entire colon, respectively.
Flexible
sigmoidoscopy
Flexible sigmoidoscopy utilizes a flexible sigmoidoscope, a flexible,
fiberoptic viewing tube with a light at its tip. It is inserted through the anus
and is used by the doctor to examine the rectum, sigmoid colon and part or all
of the descending colon. It is a shorter version of a colonoscope. It can be
useful for detecting diverticula, colon polyps, and cancers located in the
rectum, sigmoid colon, and descending colon. Flexible sigmoidoscopy also can be
used to diagnose ulcerative colitis, ulcerative proctitis, and sometimes Crohn's
colitis and ischemic colitis.
Despite its value, flexible sigmoidoscopy cannot
detect cancers, polyps, or angiodysplasias in the transverse and right colon.
Flexible sigmoidoscopy also cannot diagnose colitis that is beyond the reach of
the flexible sigmoidoscope. Because of these limitations, colonoscopy may be
necessary. The advantage of flexible sigmoidoscopy over colonoscopy is that it
can be accomplished with no preparation of the colon or after only one or two
enemas. For more information, please see the
Flexible Sigmoidoscopy
article.
Colonoscopy
Colonoscopy is a procedure that
enables an examiner (usually a gastroenterologist) to evaluate the inside of the
entire colon. This is accomplished by inserting a flexible viewing tube (the
colonoscope) into the anus and then advancing it slowly under direct vision
through the rectum and the entire colon. The colonoscope frequently can reach
the part of the small intestine that is adjacent to the right colon.
Colonoscopy
is the most widely used procedure for evaluating rectal bleeding as well as
occult bleeding. It can be used to detect polyps, cancers, diverticulosis,
ulcerative colitis, ulcerative proctitis, Crohn's colitis, ischemic colitis, and
angiodysplasias throughout the entire colon and rectum. For more information,
please see the Colonoscopy
article.
Next: Radionuclide scans »
- Colonoscopy - Learn about the colonscopy procedure, what it is, why it is performed, preparation, complications, alternatives and the after effects of the screening exam on MedicineNet.com
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