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Diarrhea
Diagnosis

Your doctor will ask about your medical history, perform a physical examination and order routine blood, urine and stool tests. Other diagnostic tests used to make a diagnosis of constipation include sigmoidoscopy and colonoscopy.

Sigmoidoscopy

For a sigmoidoscopy, the doctor uses a special instrument called a colonoscope, which is a long, flexible tube that is about as thick as your index finger and has a tiny video camera and light on the end, to exam your rectum and lower part of your colon. During the procedure, everything will be done to help you be as comfortable as possible. Your blood pressure, pulse and the oxygen level in your blood will be carefully monitored.

Your doctor will do a rectal exam with a gloved, lubricated finger; then the lubricated colonoscope will be gently inserted. As the scope is slowly and carefully passed, you may feel as if you need to move your bowels, and because air is introduced to help advance the scope, you may feel some cramping or fullness. Generally, however, there is little or no discomfort. Occasionally, some abdominal pressure, which may be provided by your nurse, or a change in position may be needed to avoid looping of the colonoscope within the abdomen. Your doctor will advance the scope until he or she has examined the left side of the colon. Afterwards, the scope is then carefully withdrawn while a thorough exam of the colon is performed. At this point in the exam, your doctor will use the colonoscope to look closely for any polyps or other problems that may require evaluation, diagnosis or treatment. The procedure typically takes between 10 and 15 minutes.

Colonoscopy

Colonoscopy is used to evaluate symptoms such as abdominal pain, bloody bowel movements, altered bowel habits such as constipation or diarrhea, and weight loss. This test is similar to sigmoidoscopy, but the doctor looks at the entire colon, rather than just the left side. The term "colonoscopy" means looking inside the colon. Colonoscopy is a procedure performed by a gastroenterologist, a well-trained specialized doctor.

Colonoscopy also is performed using a colonoscope, which is a long, flexible tube that is about as thick as your index finger and has a tiny video camera and light on the end, to exam your rectum and lower part of your colon. During the procedure, everything will be done to help you be as comfortable as possible. Your blood pressure, pulse and the oxygen level in your blood will be carefully monitored.

By adjusting the various controls on the colonoscope, the gastroenterologist can safely maneuver the instrument to carefully examine the inside lining of the colon from the anus to the cecum. The colonoscope contains a channel that allows instruments to be passed in order to take tissue or stool samples, remove polyps and provide other therapy. The high quality picture from the colonoscope, shown on a TV monitor, provides a clear, detailed view of the colon. It provides a more precise examination than X-ray studies.

Your doctor will do a rectal exam with a gloved, lubricated finger; then the lubricated colonoscope will be gently inserted. As the scope is slowly and carefully passed, you may feel as if you need to move your bowels, and because air is introduced to help advance the scope, you may feel some cramping or fullness. Generally, however, there is little or no discomfort. Occasionally, some abdominal pressure, which may be provided by your nurse, or a change in position may be needed to avoid looping of the colonoscope within the abdomen. Your doctor will advance the scope until he or she reaches the beginning of the colon, called the cecum. After reaching this point, the scope is then carefully withdrawn while a thorough exam of the colon is performed. At this point in the exam, your doctor will use the colonoscope to look closely for any polyps or other problems that may require evaluation, diagnosis or treatment. The procedure typically takes between 10 and 15 minutes.

Reviewed by health care specialists at UCSF Medical Center.

Related Information

UCSF Clinics & Centers

Gastroenterology

Gastroenterology at Mount Zion
1701 Divisadero St., Suite 120
San Francisco, CA 94115
Phone: (415) 502-4444
Fax: (415) 502-2249
Appointment information

Endoscopy at Parnassus
505 Parnassus Ave., Room L-103
San Francisco, CA 94143-1007
Phone (For appointments): (415) 353-2318
Phone: (415) 353-1702
Fax: (415) 353-2407
Appointment information

Endoscopy at Mount Zion
1600 Divisadero St., First Floor
San Francisco, CA 94115
Phone (For appointments): (415) 502-4444
Phone: (415) 885-7768
Fax : (415) 502-2249
Appointment information

Endoscopy at Parnassus
505 Parnassus Ave., Room L-103
San Francisco, CA 94143-1007
Phone (For appointments): (415) 353-2318
Phone: (415) 353-1702
Fax: (415) 353-2407
Appointment information

Gastrointestinal Motility & Secretion Center
400 Parnassus Ave., Box 0310
San Francisco, CA 94143-0310
Phone: (415) 353-9383
Fax: (415) 353-2505
Appointment information