Friday, October 12, 2007

Flexible sigmoidoscopy

INTRODUCTION — A flexible sigmoidoscopy is an examination of the lower (distal) part of the gastrointestinal tract, called the colon or large intestine (show figure 1). It is performed by an endoscopist, a doctor or other health professional with special training in endoscopic procedures. There are several reasons that flexible signmoidoscopy may be recommended, with one of the most common reasons being the need to screen for colon cancer in people older than 50 years.

Colonoscopy allows the physician to examine the entire large intestine, and is preferred over flexible sigmoidoscopy if the entire colon needs to be examined. (See "Patient information: Colonoscopy").

REASONS FOR FLEXIBLE SIGMOIDOSCOPY — The most common reasons for flexible sigmoidoscopy are the following: As a screening test to detect colon polyps or colon cancer in people over age fifty Blood in the stool or rectal bleeding (sigmoidoscopy may be recommended to evaluate bleeding) Persistent diarrhea After radiation treatment to the pelvis when a patient has lower gastrointestinal symptoms Evaluation of the colon in conjunction with a barium enema For the medical management of colitis (inflammation of the colon)

PREPARATION — Your doctor will provide you with specific Instructions on how to prepare for the examination. The instructions are designed to maximize your safety during and after the examination, minimize possible complications, and provide the endoscopist with the best look at your colon.

It is important for you to read the instructions ahead of time and follow them carefully. Call your doctor or the endoscopy unit if you have questions.

Bowel cleaning — The lower part of the colon must be cleaned to permit the endoscopist to see the inside lining of the colon. Specific instruction will be provided, although preparation usually involves consuming a clear liquid diet, laxatives, and use of an enemas shortly before the examination.

Medications — Some medications, such as aspirin products and iron preparations, should be stopped one to two weeks before the examination. Aspirin increases the risk of bleeding after the test, while iron coats the colon, making it difficult to see the lining. People who take a blood thinning medication such as warfarin (Coumadin®) should consult with their clinician regarding the need to stop taking this medication temporarily.

Most medications for high blood pressure, heart disease, lung disease, and seizure disorders are safe during sigmoidoscopy and can be taken the day of the examination.

Medications for diabetes may need to be decreased before the test; patients should talk with their diabetes clinician.

WHAT TO EXPECT — Prior to the sigmoidoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned A doctor will review the procedure, including possible complications, and will ask the patient to sign a consent form.

The procedure — Flexible sigmoidoscopy usually takes between five and fifteen minutes. It is performed while the patient lies on their left side with the legs curled up against the chest. The sigmoidoscope, which is approximately the size of one finger, is inserted into the anus and advanced through the rectum, sigmoid colon, and descending colon. The sigmoidoscope has a lens and a light source that permits the endoscopist to look into the scope or at a television monitor.

The endoscope allows the endoscopist to take biopsies (small pieces of tissue) and to introduce or withdraw fluid or air. Biopsies do not hurt because the lining of the colon does not sense pain. However, some patients will feel cramping as air is introduced through the scope and as the scope is passed through segments of the colon. The air is needed to permit the endoscopist to advance the scope and see the lining of the colon. It is common to feel embarrassed about releasing air through their rectum, although this is recommended to decrease discomfort. Let the endoscopist know if there is discomfort since air can also be removed through the scope. Because the procedure is brief and discomfort is mild, pain medications or sedation are not routinely used.

COMPLICATIONS — Flexible sigmoidoscopy is a safe procedure and complications are rare. Bleeding can occur from biopsies or the removal of polyps, but this is usually minimal and stops quickly or can be controlled. The scope can cause a tear or hole in the tissue being examined. This is a serious problem that does not occur commonly.

The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons

AFTER FLEXIBLE SIGMOIDOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Most patients are able to return to normal activities, including eating, after the examination

Patients should contact their doctor about the results of the test and if there are any questions. The endoscopy team will let the patient know when all the results will be available and if further treatment is necessary.

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 patients 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.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

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/healthtopics.html)
The American Society of Gastrointestinal Endoscopy:

(www.askasge.org)
National Digestive Disease Information Clearinghouse

(http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/index.htm)


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Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Doria-Rose, VP, Levin, TR, Selby, JV, et al. The incidence of colorectal cancer following a negative screening sigmoidoscopy: Implications for screening interval. Gastroenterology 2004; 127:714.
2. Fletcher, RH. Screening sigmoidoscopy-- how often and how good?. JAMA 2003; 290:106.
3. Levin, TR, Conell, C, Shapiro, JA, et al. Complications of screening flexible sigmoidoscopy. Gastroenterology 2002; 123:1786.

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