Colonoscopy is an internal examination of the large intestine using a small camera attached to a flexible pipe, or a colonoscope. This procedure can also take tissue samples of the colon in order to look for a microscopic changes or abnormalities. Colonoscopies need not be done in all patients, but can be used in certain cases in order to aid in proper diagnosis. Knowledge of the proper indications for colonoscopy can help patients and doctors determine when the procedure should be administered.
Screen for Colon Cancer
A colonoscopy can be used as a screening test for colon cancer, according to the National Institutes of Health. Screening is a set of procedures that can be used to search for the presence of certain diseases. Colonoscopy can be used to view the colon, or large intestine, for any lesions that may indicate colon cancer. A colonoscopic screening of normal patients should begin at age 50 and be repeated every 10 years.
Evaluation of Unexplained Gastrointestinal Bleeding
Patients who have been found to have symptoms that indicate a bleed in the colon should undergo a colonoscopy, reports the National Guideline Clearinghouse. Symptoms that may indicate such bleeding include the passing of stool that is dark black or red in color or the presence of blood within stool.
History of Polyps
Polyps are small outgrowths of tissue found in the colon. A history of polyps in the colon has been linked to colon cancer. A colonoscopy should be used to evaluate the progress of these lesions and the risk for cancer, according to a 2001 study, "Colonoscopy: Evaluating Indications and Diagnostic Yield." Colonoscopy has been documented as being able to detect the presence of polyps in at least 70 percent of cases.
Anemia
Unexplained iron-deficiency anemia is a common indication for a colonoscopy, according to the National Institutes of Health. Iron-deficiency anemia is a decreased level of blood cells due to an insufficient level of iron. This may be caused by bleeding in the colon. Colonoscopy can be used to determine if there is a bleeding wound in the colon that is causing the anemia.
Diarrhea
Patients with significant episodes of diarrhea that have yet to be explained should undergo a colonoscopy, as stated by the National Guideline Institute. If the reason for the patient's diarrhea is unknown, a colonoscopy can determine if an abnormality in the colon is the cause.
Lower Abdominal Pain
Abdominal pain can be a symptom that points to many different diseases. A colonoscopy can aid in the diagnosis of the condition causing the abdominal pain. The procedure is less than 7 percent effective, however, in finding a definitive reason for abdominal pain.
References
- National Guideline Institute: Quality indicators for colonoscopy.
- National Institutes of Health/MedlinePlus: Colonoscopy
- National Institutes of Health/MedlinePlus: Physical Exam Frequency
- Mohammed A. Al-Shamali, et al "Colonoscopy: Evaluating indications and diagnostic yield" King Faisal Specialist Hospital & Research Centre : Jeddah
