Colonoscopy

INDEX: Colonoscopy Introduction Risks Colonoscopy Preparation During the Procedure After the Procedure Next Steps When to Seek Medical Care Alternatives Considerations for the Future Synonyms and Keywords Authors and Editors

Colonoscopy Introduction

A colonoscopy is a test to look at the inside of your colon. The colon is the large intestine and the last part of your digestive system. Its job is to dry, process, and eliminate the waste left after the small intestine has absorbed the nutrients in food. The colon is about 3-5 feet long. It travels from the lower right corner of your abdomen (where the small intestine ends) up to your liver, across your body to the spleen in the upper left corner and then down to form your rectum and anus.

The doctor will use an instrument called the colonoscope to perform a colonoscopy. It is a long (about 3 ft), thin (about 1 in), flexible fiberoptic camera that allows the doctor to visualize your entire colon.

• Your doctor may order a colonoscopy to investigate many different diseases of the colon.
  
  
  • Colonoscopy is best known for its use as a screening tool for the early detection of colorectal cancer.
    
    
    • Colorectal cancer is the second leading cause of cancer deaths in the United States.
      
      
    • Colon cancer develops from growths within the wall of the intestine such as polyps or tumors.
      
      
    • These growths often take 5-10 years to develop and may not cause many symptoms.
      
      
    • You may not have any symptoms of colon cancer, but having a close relative with the disease increases your risk for the disease compared to the general public.
      
      
    • Most people who develop polyps do so after age 50, so the American College of Gastroenterology (the digestive specialists) recommends screening examinations every 5 years for early detection and removal of these cancer-causing growths after that age.
    
    
  • Colonoscopy is also used to investigate other diseases of the colon.
    
    
    • Colonoscopy may be used to find the place and cause of bleeding as well as to check areas for irritation or sores in your colon.
      
      
    • These colon problems can cause unexplained changes in bowel habits.
      
      
    • Pain, bloody diarrhea, and weight loss can be caused by inflammation of the bowel, which may be the result of Crohn disease or ulcerative colitis.
      
      
    • These inflammatory digestive diseases tend to occur in young adults and, if undetected, can produce chronic symptoms and increase the risk of colon cancer.
  
  
• Colonoscopy is used when there is concern that a disease of the colon may exist.
  
  
  • Your doctor may recommend this test if other screening tests such as a manual rectal examination, a hemoccult test to find hidden blood in your feces, or a barium enema (a test in which barium is used to make your colon visible on an x-ray) suggest that further information is needed to make a diagnosis.
    
    
  • A colonoscopy may be required when symptoms of digestive disease or other warning signs are present.
    
    
    • Rectal bleeding (which may appears as bright red, very dark, or black)
      
      
    • Pain in the lower abdomen
      
      
    • Changes in bowel habits
      
      
    • Nondietary weight loss
    
    
  • Only doctors who specialize in the study of digestive disease, have special training in endoscopy, and are certified to perform colonoscopy qualify to perform this procedure.
    
    
    • As with any skill, performance improves with experience.
      
      
    • The American Society for Gastrointestinal Endoscopy suggests that a doctor perform at least 200 procedures to become technically competent at diagnostic colonoscopy.

Risks

As with any procedure, there are risks associated with a colonoscopy. Before obtaining your consent for the procedure, your doctor will tell you about the potential risks.

• The most common side effects are cramping pain and abdominal swelling caused by the air used to inflate the colon during the procedure. This air is expelled shortly after the procedure, and these symptoms generally go away.
  
  
• If a biopsy is performed during the procedure, you may also note small amounts of blood in the bowel movements after the examination. This may last for a few days.
  
  
• Though rare, there is potential for the colonoscope to injure the intestinal wall, causing perforation, infection, or bleeding.
  
  
• Although this test is very helpful in finding the cause of many digestive diseases, abnormalities can go undetected at times. Factors that can affect this include the completeness of your bowel preparation before the procedure, the skill of the operator of the colonoscope, and your anatomy.
  
  
• When this test is performed, you will be given sedating medications to make the test more comfortable. Whenever a medication is given, a risk of an allergic reaction or side effect of the medication itself is present. These IV medications are given under medical supervision, and you will be monitored during the procedure to lessen the risk of medication-related complications.

Colonoscopy Preparation

A colonoscopy can be carried out in a hospital, clinic, or in a doctor’s office, depending on the facility. You will be given an appointment and a set of instructions to follow before the test is performed.

• Although the exact instructions given may vary from clinic to clinic, their objective is the same: to clean out the contents of the bowel before the test.
  
  
• This allows the bowel wall to be seen during the test.
  
  
• This system of cleaning the bowel is often called bowel preparation.
  
  
• You will be given a combination of liquid diet, laxatives, or enemas for up to 2 days prior to the test with instructions on how to use them. Several medications are available for bowel cleansing, including polyethylene glycol 3350 (GoLYTELY, NuLYTELY), magnesium citrate (Citroma), and senna (X-Prep).

• These medications produce diarrhea, which can be uncomfortable, but unless the bowel is empty of stool, the test can be limited and may need to be repeated at a later date.
  
  
• On the night before the test is to be performed, nothing should be taken by mouth (food or liquids) until after the test is finished.

During the Procedure

• On the day of the colonoscopy, you will most likely be asked to arrive at the clinic up to an hour before the test is due to begin. This is to allow time to get ready for the test itself and to ask further questions. In addition, you will be asked the following questions:
  
  
  • When did you last eat?
    
    
  • What allergies do you have?
    
    
  • Did you remember to take all your bowel preparation medication?
• 
  
• Once you are undressed and changed into an examination gown, your vital signs (blood pressure, heart rate, respiration rate, and temperature) will be monitored and an intravenous line (IV) will be placed. This IV is necessary to give you sedation and pain medication that may be required during the test. Although you will not be fully asleep during the procedure, these medications will produce a sleepy state (sedation) and make the test more comfortable.
  
  
• The procedure will begin with you lying flat on your left side. The equipment used, the colonoscope, is lubricated to allow it to enter the anus. For a thorough investigation, air is required to gently open the folded colon. This may cause a temporary uncomfortable bloated sensation. When the doctor applies gentle pressure, the colonoscope moves further into the colon and is slowly advanced until the entire colon is seen.
  
  
• The colonoscope has a tiny camera on the end of it, which is connected to a monitor. This allows the physician to see the colon through the tip of the instrument even when it is far inside the body. As the scope passes the course of the colon, the normal turns and contours of the colon may impede the passage of the scope. You may be asked to change positions for better visualization. It is common for fluid and gas to escape through the rectum and anus; this should be expected. The entire procedure can take from 30 minutes up to 1 hour.
  
  
• In addition to simply viewing the bowel wall, the colonoscope has special attachments that allow the doctor to collect tissue samples or biopsies, remove small growths, and stop bleeding with laser, heat, or medication.

After the Procedure

When the colonoscopy is done as an outpatient procedure (without checking into the hospital), you will go home later that same day. But before you go home, you will be observed for some time and monitored until the effects of the medications are gone. It is a good idea to make arrangements for someone to come to the clinic and take you home, because nausea, bloating, and drowsiness can continue for some time after the procedure.

Next Steps

Upon discharge, the doctor will give you a follow-up appointment. The final results of the test are generally available at that appointment, although biopsy results may take some time. In addition, the doctor may give you specific instructions regarding what symptoms to watch for, which ones are normal, and which are more serious. You may also be advised when to start eating and told to slowly increase dietary intake.

When to Seek Medical Care

• You should feel comfortable calling your doctor if any unexpected symptoms occur. These symptoms include the following:
  
  
  • Persistent nausea
    
    
  • Persistent but minor bleeding
    
    
  • Ongoing bloating and abdominal discomfort
    
    
• If you have additional concerns, call the doctor’s office for advice and evaluation.
  
  
• Although minor symptoms, such as bloating, are common after this procedure, more serious symptoms should prompt you to seek urgent medical attention. You should call your physician and go directly to the emergency department if you experience any of the following:
  
  
  • Severe abdominal pain
    
    
  • Heavy bleeding from the anus
    
    
  • Fever
    
    
  • Vomiting

Alternatives

Other tests exist that can help your doctor to detect diseases of the colon. Sometimes these tests can be done instead of a colonoscopy, but at other times they are performed in addition to a colonoscopy because each test can provide different types of information.

• With similar preparation, a special x-ray examination of the entire colon, a barium enema, can be used instead of or in addition to colonoscopy. For this test, a liquid called barium is inserted into the colon using a small tube through the anus. X-rays are then taken of the abdomen with the barium inside. This liquid is seen on the x-ray and is used to outline the irregularities of the bowel wall.
  
  
• Another test called a sigmoidoscopy can be performed. This test is very similar to a colonoscopy but requires less preparation. The instrument used, a sigmoidoscope, is 2 ft long and allows visualization of the anal canal, rectum, and the part of the colon closest to the rectum known as the sigmoid colon. Although this test is important, it does not allow detection of abnormalities in other areas of the colon because the sigmoidoscope is much shorter than the colonoscope.
  
  
• CT scans are often used to investigate abnormalities of the abdomen. Gastrografin is a liquid similar to barium, which allows the bowel to be seen better during a CT scan. This liquid, also called oral contrast, is swallowed and then allowed to pass from the stomach, through the small intestine (the ileum) and then through the large intestine (the colon) before the CT scan is performed. In this way, a CT scan can be helpful to investigate abdominal and bowel problems.
  
  
• Your doctor will decide which of these tests is most appropriate for you.

Considerations for the Future

In an effort to develop a safe, efficient, and comfortable screening exam for colorectal cancer, the development of a test called virtual colonoscopy has received increasing interest. This technique involves similar preparation of the bowel and computerized manipulation of a series of abdominal and pelvic CT scan images. Initial studies appear promising. More studies are required, however, to prove that this procedure is just as accurate.

The American Cancer Society recently revised its recommendations for colorectal screening to include an emphasis on the examination of the entire colon. Despite this, 80% of American adults do not undergo screening. Currently, colonoscopy is the only technique available to directly look at, biopsy, and potentially treat digestive diseases of the large intestine.

Synonyms and Keywords

colon, large intestine, digestive system, colorectal cancer, colon cancer, Crohn disease, disease of the colon, digestive disease, endoscopy, sigmoidoscopy, barium enema, colonoscope, cramping pain, abdominal swelling, CT scan, virtual colonoscopy, colorectal screening, colonoscopy test, colonoscopy

Authors and Editors

Author: R Benjamin Saldana, DO, Staff Physician, Department of Emergency Medicine, Lincoln Medical and Mental Health Center, Cornell University.

Coauthor(s): Mary T Ryan, MD, Clinical Instructor, Department of Medicine, Department of Emergency Medicine, Lincoln Medical and Mental Health Center.

Editors: Scott H Plantz, MD, FAAEM, Research Director, Assistant Professor, Department of Emergency Medicine, Mount Sinai School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, Pharmacy, eMedicine; Steven L Bernstein, MD, Vice-Chair, Academic Affairs, Department of Emergency Medicine, Newark Beth Israel Medical Center; Assistant Professor, Department of Emergency Medicine, Mt Sinai School of Medicine.

© 2004 eMedicine.com, Inc.
All Rights Reserved.

Medicine is a constantly changing science, and clearly established therapies are not always available for every condition. New research findings necessitate continual changes in drug and treatment therapies. The authors, editors, and publisher of this journal have used reasonable efforts to provide up-to-date, accurate information that is within generally accepted medical standards at the time of publication. However, as medical science is ever evolving, and human error is always possible, the authors, editors, and publisher (or any other involved party) do not guarantee total accuracy or comprehensiveness of the information in this article, nor are they responsible for omissions, errors, or the results of using this information. The reader should confirm the accuracy of the information in this article from other sources. In particular, all drug doses, indications, and contraindications should be confirmed in package inserts. FULL DISCLAIMER

HalfLytely and Bisacodyl Tablets Bowel Prep Kit is a medicine to clean out the colon (intestines) before a colonoscopy. Nausea, stomach cramping, and abdominal fullness are the most common side effects. These happen in up to 50% of patients.

You should not use this product if you are allergic to anything in it. You should also not use this product if your intestines are blocked or larger than normal or if you have a stomach problem called gastric retention, or an inflammation of your large intestines. If you have severe ulcerative colitis, tell your doctor before using this product. Any woman who is pregnant or who thinks she might be should tell her doctor before using this product. This product has not been studied in pediatric patients and pregnant women.

Do not add anything else, such as flavorings, to the solution. Do NOT chew or crush the bisacodyl delayed-release tablets. If you have severe discomfort or distention (bloating), stop drinking the solution for a while. You can also wait longer between drinking each glass of solution until the discomfort goes away. Any medicines you take within 1 hour of starting to drink the solution may be flushed out of your body by the solution. You should avoid drinking large amounts of water during or after taking this product or after a colonoscopy.

Click here for important product information