An overview of Colonoscopy
A colonoscopy is a medical exam used to examine the large intestine (colon) and rectum for any abnormalities, such as polyps, cancer, or inflamed tissues. During the procedure, a long, flexible tube with a camera at the tip (colonoscope) is inserted into the rectum, allowing the doctor to view the inside of the entire colon on an external monitor. Air or carbon dioxide may be introduced to inflate the colon for better visibility. If necessary, polyps or other tissue samples can be removed for further examination. A colonoscopy typically takes around 30 to 60 minutes and is performed under sedation to minimize discomfort. The test is commonly used to investigate intestinal symptoms, screen for colon cancer, or treat certain issues such as placing a stent or removing an object in the colon.
What is Colonoscopy used for?
A colonoscopy is used to detect changes in the large intestine (colon) and rectum, such as swollen, irritated tissues, polyps, or signs of cancer. It helps doctors investigate intestinal symptoms, screen for colon cancer, look for additional polyps, and sometimes for treatment purposes like placing a stent or removing an object in the colon.
How often should Colonoscopy be performed?
The frequency of colonoscopy tests depends on a person's individual risk factors and previous medical history. For people at average risk of colon cancer, with no risk factors other than age, a colonoscopy is recommended every 10 years if they are 45 years or older. However, if you have other risk factors or a history of polyps, your doctor may recommend a screening sooner. The frequency may also depend on the number, size, and type of polyps found during previous colonoscopies, as well as family history and genetic syndromes. In some cases where there was residual stool preventing a complete examination, a repeat colonoscopy may be recommended sooner based on the amount of stool and the extent of the colon examined. Your doctor will provide personalized recommendations based on your specific circumstances.
How to prepare for Colonoscopy?
Patient preparations are necessary before a colonoscopy test. To prepare for the exam, you should:
- Inform your doctor about your medications: Mention any medications you are taking, especially if you have diabetes, high blood pressure, or heart problems, or if you are on medications or supplements containing iron. You should also let your doctor know if you are taking aspirin, blood-thinning medications, or any heart medications that affect platelets.
- Follow a special diet: You may need to follow a special diet the day before the exam, which typically involves not eating solid food and limiting your drinks to clear liquids like plain water, tea, and coffee without milk or cream, broth, and carbonated beverages. Red liquids should be avoided, as they may be mistaken for blood during the colonoscopy.
- Take a laxative: Your doctor may recommend taking a prescription laxative, usually the night before your colonoscopy, to empty your colon.
- Discuss any concerns or risks: Talk to your doctor about any concerns you may have and discuss the potential risks associated with the colonoscopy procedure.
Remember to follow your doctor's instructions carefully to ensure a successful and safe colonoscopy.
How is Colonoscopy conducted?
A colonoscopy is conducted by inserting a long, flexible tube called a colonoscope into the rectum. The colonoscope contains a light, a tube for introducing air or carbon dioxide, and a tiny video camera at its tip. The camera sends images to an external monitor, allowing the doctor to view the inside of the entire colon. If necessary, the doctor can insert instruments through the channel to take tissue samples or remove polyps and other abnormal tissue. The colonoscopy typically takes 30 to 60 minutes.
How are Colonoscopy results reported?
Colonoscopy results are typically reported as negative or positive. A negative result means that the doctor did not find any abnormalities in the colon. In this case, the doctor may recommend another colonoscopy in 10 years if the person is at average risk of colon cancer and has no additional risk factors. A positive result indicates that the doctor found polyps or abnormal tissue in the colon. Depending on the size and number of polyps, the doctor may recommend a repeat colonoscopy at an earlier date or more frequent surveillance in the future.
Understanding the report
A colonoscopy is considered negative if the doctor doesn't find any abnormalities in the colon. If your doctor finds polyps or abnormal tissue, the colonoscopy is considered positive. Your doctor may recommend a repeat colonoscopy in 7 to 10 years, depending on the size and number of polyps, your other risk factors for colon cancer, and the presence of residual stool in the colon that prevents complete examination. If you experience persistent abdominal pain, abnormal blood in your stool, or a fever after the colonoscopy, consult your doctor.
Limitations and Considerations
Colonoscopy is a valuable diagnostic and screening tool, but it does have some limitations. Here are some key limitations to consider:
- Requires bowel preparation: A successful colonoscopy depends on the colon being free of stool. This requires thorough bowel preparation, which may be uncomfortable, inconvenient, and sometimes incomplete. If the colon is not properly cleaned, the doctor may not be able to get a clear view of the entire colon and rectum.
- Limited detection of small polyps: The accuracy of colonoscopy in detecting small polyps (<5 mm) or flat polyps is lower compared to larger polyps. Smaller polyps may be missed, which could lead to a delay in diagnosis and treatment.
- Incomplete examination of the colon: In some cases, the colonoscope may not be able to reach certain areas of the colon, particularly if the patient has a narrow or tortuous colon. This may result in an incomplete examination of the colon.
- Interpretation subjectivity: The interpretation of colonoscopy findings can be subjective. Different doctors or gastroenterologists may have varying opinions on the presence or significance of polyps, abnormal tissues, or other findings.
- Risks and complications: While the risks of colonoscopy are generally low, they do exist. Complications may include reactions to sedatives, bleeding, perforation, or difficulty in removing polyps or other abnormal tissues. It is important to discuss the benefits and limitations of colonoscopy with your doctor to determine if it is the right test for your specific situation.