An anoscopy is an examination of the rectum in which a small tube is inserted into the anus to screen, diagnose, and evaluate problems of the anus and anal canal.
This test may be ordered for the evaluation of perianal or anal pain, hemorrhoids, rectal prolapse, digital rectal examination that shows a mass, perianal abscess and condyloma (a wart-like growth). An anascopy may be performed to check for abnormal openings between the anus and the skin, or anal fissures. The test is also used to diagnose rectal cancer.
Anoscopy should not be performed on patients with acute cardiovascular problems due to the vasovagal reaction it may cause. This test is also not recommended for patients with acute abdominal problems and those with a constricted or narrowed anal canal.
Anoscopy views the anus and anal canal by using an anoscope. An anoscope is a plastic, tube-shaped speculum that is a smaller version of a sigmoidscope. Before the anoscope is used, the doctor completes a digital rectal examination with a lubricated, gloved index finger. The anoscope is then lubricated and gently inserted a few inches into the rectum. This procedure enlarges the rectum to allow the doctor to view the entire anal canal with a light. If any suspicious areas are noticed, a piece of tissue can be biopsied.
During the anoscopy procedure there may be a feeling of pressure or the need to go to the bathroom. If a biopsy is taken, the patient may feel a slight pinch. The procedure is performed on an out-patient basis, and takes approximately an hour to complete.
The patient will be instructed to clear their rectum of stool before the procedure. This may be done by taking a laxative, enema, or other preparation that may help with the evacuation.
If a biopsy is needed during an anoscopy, there may be slight anal bleeding for less than two days following the procedure. The patient may be instructed to sit in a bathtub of warm water for 10 to 15 minutes, three times a day, to help decrease the pain and swelling.
A simple anoscopy procedure offers minimal risks. There is a limited risk of bleeding and mild pain is a biopsy is performed.
Normal values to look for during an anoscopy include an anal canal that appears healthy in size, color, and shape. The test also looks for no evidence of bleeding, polyps, hemorrhoids or other abnormalities.
While an anoscopy is typically performed to determine is hemorrhoids are present, other abnormal finding could include polyps, abscesses, inflammation, fissures, colorectal polyps, or cancer.
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Anal fissure— An ulcer on the margin of the anus.
Digital rectal examination— An examination where a gloved, lubricated index finger is inserted into the rectum to check for any abnormalities.
Polyps— A tumor with a small flap that attaches itself to the wall of various vascular organs such as the nose, uterus and rectum. Polyps bleed easily, and if they are suspected to be cancerous they should be surgically removed.
Vasovagal reaction— Regarding the action of stimuli from the vagus nerve on blood vessels.
Anoscopy is a diagnostic procedure that allows a gastroenterologist or other physician to visually examine the rectum, anus, and anal canal.
Doctors use anoscopy to diagnose rectal cancer and cancer of the anus. This procedure can also help the doctor:
- detect any lesions that could not be felt during a digital examination
- determine whether squamous cell carcinomas involving lymph nodes in or near the groin (inguinal lymph nodes) originated in the genital area or in or near the anus or rectum
- confirm the source of malignancies that have spread to the anorectal area from other parts of the body
Doctors also perform anoscopy to determine whether a patient has hemorrhoids or anal:
- growths or nodules (polyps)
- ulcer-like grooves (fissures)
After removing underwear, the patient bends forward over the examining table or lies on one side with knees drawn up to the chest. The doctor performs a digital examination to make sure no tumor or other abnormality will obstruct the passage of a slender lubricated tube (anoscope). As the doctor gently guides the anoscope a few inches into the rectum, the patient is told to bear down as though having a bowel movement, then relax.
By tensing and relaxing, the patient makes it easier for the doctor to insert the anoscope, and discover growths in the lining of the rectum that could not be detected during the digital examination.
Directing a light into the anoscope gives the doctor a clear view of any tears or other irregularities in the lower anus or rectum. A doctor who suspects that a patient may have cancer will remove tissue for biopsy in the course of this procedure.
Slowly withdrawing the anoscope allows the doctor to thoroughly inspect the entire anal canal. As the procedure is being performed, the doctor explains what is happening, and why the patient feels pressure.
Removing tissue samples for biopsy can pinch, but anoscopy does not usually cause pain. Patients do experience the sensation of needing to have a bowel movement.
The rectum should be emptied of fecal matter (stool) before the procedure is performed. The doctor may suggest using:
- a laxative,
- an enema,
- or some other preparation
to clear the recturn
As soon as the procedure is completed, the doctor can tell the patient whether the results are normal or abnormal, and the patient can resume normal activities.
Removing tissue for biopsy may cause a little bleeding and some slight pain, but there are no significant risks associated with anoscopy.
A normal anoscopy reveals no evidence of:
- tissue irregularities
or other abnormalities. The size, color, and shape of the anal canal look like they should.
Abnormal results of anoscopy can indicate the presence of:
See Also Anal cancer; Digital rectal examination
Cahill, Matthew. Everything You Need To Know About Medical Treatments. Springhouse, PA: Springhouse Corporatioon, 1996.
Anoscopy <http://www.thriveonline.oxygen.com/medical/library/article/003890.html>. 14 May 2001.
—Pertaining to the anus and rectum
—The opening of the rectum through which feces leave the body
—The portion of the large intestine where feces is stored before leaving the body
QUESTIONS TO ASK THE DOCTOR
- Why do you want me to have an anoscopy?
- How long will this procedure take?
- What will the results of this test tell you?