Understanding Colonoscopy
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What is a colonoscopy?

Colonoscopy enables your doctor to examine the lining of your colon (large intestine) for
abnormalities by inserting a flexible tube as thick as your finger into your anus and slowly
advancing it into the rectum and colon. Please ask your doctor about anything you don't

THE PROCEDURE — The colonoscopy will be performed with you lying on your left side.
Medications will be administered through the intravenous line. Most endoscopy units
administer a combination of a sedative, to help you relax, and a narcotic, to diminish any
unpleasant sensations. Many people sleep during the examination and others are very
relaxed, comfortable, and generally not very aware of the examination.

The colonoscope is a flexible tube, approximately the size of your index finger. It has a
lens and a light source that allows the endoscopist to look into the scope or at a TV
monitor. The image on the TV monitor is magnified many times so the endoscopist can
see minute changes in tissue.

The endoscope contains channels that allow the endoscopist to obtain biopsies (small
pieces of tissue), remove polyps and to introduce or withdraw fluid or air. Neither of these
hurt since the lining of the colon does not have that type of pain sensation.

Air is introduced through the scope to open up the colon so that the scope can be moved
forward and to allow the endoscopist to see. You may experience a feeling of bloating or
gas cramps from the air as it distends the colon. Do not be embarrassed about releasing
the air through your rectum if you can. It is important for you to let the doctor know if you
are uncomfortable.

What if the colonoscopy shows something abnormal?

If your doctor thinks an area needs further evaluation, he or she might pass an
instrument through the colonoscope to obtain a biopsy (a sample of the colon lining) to
be analyzed. Biopsies are used to identify many conditions, and your doctor might order
one even if he or she doesn't suspect cancer. If colonoscopy is being performed to
identify sites of bleeding, your doctor might control the bleeding through the colonoscope
by injecting medications or by coagulation (sealing off bleeding vessels with heat
treatment). Your doctor might also find polyps during colonoscopy, and he or she will
most likely remove them during the examination. These procedures don't usually cause
any pain.

What are polyps and why are they removed?

Polyps are abnormal growths in the colon lining that are usually benign (noncancerous).
They vary in size from a tiny dot to several inches. Your doctor can't always tell a benign
polyp from a malignant (cancerous) polyp by its outer appearance, so he or she might
send removed polyps for analysis. Because cancer begins in polyps, removing them is
an important means of preventing Colo-rectal cancer.

How are polyps removed?

Your doctor might destroy tiny polyps by fulguration (burning) or by removing them with
wire loops called snares or with biopsy instruments. Your doctor might use a technique
called "snare polypectomy" to remove larger polyps. That technique involves passing a
wire loop through the colonoscope and removing the polyp from the intestinal wall using
an electrical current. You should feel no pain during the polypectomy.

What preparation is required?

Your doctor will tell you what dietary restrictions to follow and what cleansing routine to
use. In general, the preparation consists of either consuming a large volume of a special
cleansing solution or clear liquids and special oral laxatives. The colon must be
completely clean for the procedure to be accurate and complete, so be sure to follow
your doctor's instructions carefully.

Can I take my current medications?

Most medications can be continued as usual, but some medications can interfere with the
preparation or the examination. Inform your doctor about medications you're taking,
particularly aspirin products, arthritis medications, anticoagulants (blood thinners), insulin
or iron products. Also, be sure to mention allergies you have to medications.

Alert your doctor if you require antibiotics prior to dental procedures, because you might
need antibiotics before a colonoscopy as well.

WHAT TO EXPECT IN THE ENDOSCOPY UNIT — Prior to the colonoscopy, a nurse will
prepare you for the examination. The nurse will take a history to determine what you
already know about the procedure and whether you understand why the examination is
being done. Other questions that you should be prepared to answer include:

Have you taken the bowel preparation prescribed to you and followed the clear liquid  

Do you have an escort home?

What medications do you take?

Do you have any medical problems, such as heart disease or lung disease?

Do you have allergies to any medications or latex allergies?

Have you had any previous adverse reactions to sedation medications (such as Valium
or Versed) or narcotics (such as Demerol, fentanyl, morphine)?

The nurse will start an intravenous line (put a needle in a vein in your arm) to administer
medications to help you relax and keep you comfortable during the examination. This is
just a pin prick, no worse than having your blood drawn. Your vital signs will be monitored
during the examination and for a time after the colonoscopy is over. The nurse will check
your blood pressure and pulse either manually or with a machine that continuously
monitors your heart rate and rhythm, your oxygen level, and blood pressure. The
monitoring machines are not painful. You may also be given oxygen during the

The consent — A doctor will review the examination with you, including possible
complications, and will ask you to sign a consent form. He will answer any questions you
may have about the examination.

RECOVERY — After the colonoscopy, you will be kept for a time for observation while
some of the medicine wears off. The most common discomfort after the examination is a
feeling of bloating and gas cramps. You may also be very groggy from the sedation
medications or you may have difficulty concentrating. It is usually advised that you not
return to work that day. Unless you are given other instructions, you should be able to
eat a regular diet after the examination. You should ask your doctor when it is safe to
restart aspirin or blood thinning medications.

COMPLICATIONS — Colonoscopy is a safe procedure and complications are rare, but
can occur:

Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and
stops quickly or can be controlled.

The colonoscope can cause a tear or hole in the tissue being examined, which is a
serious problem, but, fortunately, very uncommon.

Adverse reactions to the medications used to sedate you are possible. The endoscopy
team (doctors and nurses) will ask you about previous medication allergies or reactions
and about health problems such as heart, lung, kidney, or liver disease. Providing this
information to the team ensures a safer examination. You will also be carefully monitored
throughout the examination.

The medications can also produce irritation in the vein at the site of the intravenous line.
If redness, swelling, or warmth occur, warm to hot wet towels applied to the site may
relieve the discomfort. If the discomfort persists, notify your doctor or the endoscopy unit.

The following symptoms should be reported immediately:

Severe abdominal pain (not just gas cramps)

A firm, distended abdomen



Bleeding greater than a few tablespoons.

AFTER COLONOSCOPY — Although patients worry about discomforts of the
examination, most people tolerate it very well and feel fine afterwards. Some fatigue after
the examination is common. You should plan to take it easy and relax the rest of the day.

You should contact your doctor about the results of your test if you have any questions
and especially if biopsies were taken. The endoscopy team can give you some guidelines
as to when your doctor should have all the results and whether further treatment will be
necessary. Most patients who had polyps removed will require a repeat colonoscopy
within three to five years.
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