Patient information: Colonoscopy

COLONOSCOPY OVERVIEW

A colonoscopy is an examination of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel). Colonoscopy is a safe procedure that provides information other tests may not be able to give. Patients who require colonoscopy often have questions and concerns about the procedure.

Colonoscopy is performed by an endoscopist, who is a doctor with special training in endoscopy procedures. The colonoscope is inserted into the anus and advanced through the entire colon (to the cecum) and possibly a short distance into the small intestine (figure 1). The procedure generally takes between twenty minutes and one hour.

REASONS FOR COLONOSCOPY

The most common reasons for colonoscopy are to evaluate the following:

• As a screening exam for colon cancer in anyone over age 50
• Abnormal stools (bloody, dark-colored)
• Persistent diarrhea
• Iron deficiency anemia (a decrease in blood count due to loss of iron)
• A family history of colon cancer
• A previous history of colon polyps or colon cancer
• Chronic, unexplained abdominal pain

COLONOSCOPY PREPARATION

Your doctor's office will provide specific instructions about how you should prepare for the examination. The instructions are designed to keep you safe during and after the examination, minimize possible complications, and allow the endoscopist to fully view your colon.

It is important to read the instructions ahead of time and follow them carefully; if you have questions, you should speak with your doctor's office.

Medications — Some medicines, such as aspirin, non-prescription pain medicines (ibuprofen [Advil®, Motrin®, Nuprin®]), and iron supplements, should be stopped one to two weeks before the test. If you take a blood thinning medication (eg, warfarin/Coumadin®, aspirin, clopidogrel/Plavix®), talk with your doctor or nurse about when you should stop taking it.

You should also ask about medicines for diabetes, heart or lung disease, high blood pressure, or seizure disorders. You should not stop taking some medicines, and many medicines can be taken before the test.

What to eat — As a general rule, you should not eat any solid food for at least one day before the examination. You may drink clear liquids up to 5 hours before your procedure, including:

• Water
• Clear broth (beef, chicken, or vegetable)
• Coffee or tea (without milk)
• Ices
• Gelatin (avoid red gelatin)
• Fruit juices, such as apple, grapefruit, and lemonade (avoid red juices)

Bowel emptying — You will need to use a treatment to empty out your bowels before the colonoscopy. The most common treatment is a powder that you mix with water and drink. This solution (Go-Lytely®, Half-Lytely® and others) causes you to have diarrhea. It comes in several flavors, which, unfortunately, only partially hide the unpleasant taste. Most doctors do not recommend that you add other flavorings to the solution.

Refrigerating the solution may make it easier to drink. Drinking this solution may be the most unpleasant part of the examination. If you become nauseated or vomit while drinking the solution, call your doctor or nurse for instructions. (See "Bowel preparation for colonoscopy".)

Transportation home — You will be given a sedative (a medication to help you relax) during the colonoscopy, so you will need someone to take you home after your test. Although you will be awake by the time of discharge, the sedative medicines cause changes in reflexes and judgment that can interfere with your ability to make decisions, similar to the effect of alcohol.

WHAT TO EXPECT

Before the test, a nurse will ask questions to be sure you understand the procedure and the reason it is planned. A doctor will also review the test, including possible complications, and will ask you to sign a consent form.

The nurse will start an IV line in your hand or arm. Your vital signs (blood pressure, heart rate, and blood oxygen level) will be monitored before, during, and after the examination.

THE COLONOSCOPY PROCEDURE

The colonoscopy will be performed while you lie on your left side. Medications will be given through the IV line to help you relax and to prevent pain. Many people sleep during the test while others are very relaxed, comfortable, and generally not aware.

The colonoscope is a flexible tube, approximately the size of the 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 doctor can see small changes in tissue.

During the procedure, the doctor may take a biopsy (small pieces of tissue) or remove polyps, if needed. Polyps are extra growths of tissue that can range in size from the tip of a pen to several inches. Most polyps are benign (not cancerous). However, some polyps can become cancerous if allowed to grow for a long time. As a result, they are usually removed so they can be analyzed. This does not hurt since the lining of the colon does not sense pain. (See "Patient information: Colon polyps" and "Endoscopic removal of large colonic polyps".)

The doctor also uses the scope to introduce air, which opens up the colon and allows the scope to move forward. You may experience a feeling of bloating or gas cramps from the air as it opens the colon. Try not to be embarrassed about passing this air through the rectum, and let your physician know if you are uncomfortable.

RECOVERY FROM COLONOSCOPY

After the colonoscopy, you will be observed in a recovery area until the effects of the sedative medication wear off. The most common complaint after colonoscopy is a feeling of bloating and gas cramps. You may also feel groggy from the sedation medications. You should not return to work that day. Most people are able to eat normally after the test. Ask about when it is safe to restart aspirin or blood thinning medications.

COLONOSCOPY 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.
• The colonoscope can cause a tear or hole in the tissue being examined, which is a serious problem, but, fortunately, very uncommon.
• It is possible to have side effects from the medications used to sedate you.
• The medications can cause irritation in the vein at the site of the IV line. If you develop redness, swelling, or warmth, apply a warm wet towel to the site. If the discomfort persists, call your healthcare provider.

You should call your doctor immediately if you have any of the following:

• Severe abdominal pain (not just gas cramps)
• A firm, bloated abdomen
• Vomiting
• Fever
• Rectal bleeding (greater than a few tablespoons).

AFTER COLONOSCOPY

Although many people worry about being uncomfortable during a colonoscopy, most people tolerate it very well and feel fine afterwards. It is normal to feel tired afterwards. You should plan to take it easy and relax the rest of the day.

The doctor can describe the results of the colonoscopy before you leave the endoscopy unit. If s/he took biopsies or polyps, you should call for results within one to two weeks.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Colon polyps

Professional Level Information:
Bowel preparation for colonoscopy
Endoscopic diagnosis of inflammatory bowel disease
Endoscopic removal of large colonic polyps
Gastroenterologic procedures in patients with disorders of hemostasis
Postpolypectomy hemorrhage
Procedural sedation for gastrointestinal endoscopy: Recommendations
Role of propofol and options for patients who are difficult to sedate for gastrointestinal endoscopy
Screening for colorectal cancer: Strategies in patients at average risk
Sedation-free gastrointestinal endoscopy
Tattooing and other methods for localizing colonic lesions
Tests for screening for colorectal cancer: Stool tests, radiologic imaging and endoscopy
Wireless video capsule endoscopy

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/colonoscopy.html)

• American Gastroenterological Association

      (www.gastro.org/wmspage.cfm?parm1=858)

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