- What is a colonoscopy?
- When is it used?
- What is the preparation for the exam?
- What will happen during the exam?
- What are the risks of the procedure?
- What should I do after the procedure?
What is a colonoscopy?
Colonoscopy is the endoscopic examination of the colon (large intestine) and often also of the terminal ileum (the final part of the small intestine). In addition to inspecting the intestinal surface, colonoscopy also allows for the performance of biopsies that can be useful in establishing a diagnosis. Therapeutic procedures can also be performed during colonoscopy, among which the most frequent is the removal of polyps (polypectomy).
When is it used?
Colonoscopy is the most direct and complete way to check the mucosa of the entire colon. It is generally done for one of the following reasons:
Prevention and early detection of cancer:
A colonoscopy can help find small warts (polyps), which can become cancer. Polyps can be removed before they become cancer. The exam can also allow your doctor to find cancerous tumors early, when cancer is easier to cure.
If you are over 50 years old, you should have a colonoscopy. If you have a personal or family history that increases your risk, your doctor may recommend that you start the exam at an earlier age.
Diagnosis of a disease:
If you have symptoms and still do not have a diagnosis, you may have to undergo this exam to try to find the cause. For example, if you are having abdominal pain, chronic diarrhea, change in bowel habits, or bleeding in the stool. Through colonoscopy, your doctor can check for any irritation of the mucosa or diverticula in the intestinal wall that may justify these symptoms.
What is the preparation for the exam?
For the performance of colonoscopy, it is very important to do an intestinal preparation so that the residues are removed from the inside of the colon and thus the exam can be done with maximum safety and efficacy. Usually, for intestinal preparation, a diet is recommended in the days preceding the exam, laxatives, and possibly enemas. Make sure to complete the intestinal preparation. The exam may not be performed if the colon still has feces. In addition, if the preparation is inadequate, small polyps or lesions may not be seen by the doctor, thus impairing the quality of the exam and consequently your health as well.
Drink plenty of clear liquids during the intestinal preparation to avoid dehydration. It is useful to drink liquids that help replenish electrolytes that you lose during the preparation. For example, you can drink “sports drinks” in any color, except red or purple.
The exam takes about 20 to 30 minutes. However, you will need to plan to stay at the clinic for about 2 hours for registration, examination, and recovery. The presence of an adult companion is mandatory.
What will happen during the exam?
After the colon preparation, the patient is taken to the examination room where they will be sedated. Sedation is performed intravenously and helps the patient to sleep and relax. The colonoscope is then inserted through the rectum to the cecum (initial portion of the colon) or to the terminal ileum (final portion of the small intestine). During the withdrawal of the device, a meticulous inspection is done identifying any changes.
If necessary, small tissue samples (biopsies) can be collected during the exam for detailed microscopic analysis. Don’t worry, it doesn’t hurt.
In the presence of elevated lesions (polyps), the doctor may perform, depending on the case, the removal of the lesion (polypectomy) during the exam. The samples removed during the exam (biopsies or polyps) are sent to the pathology laboratory for analysis. The result of the analysis should be collected directly from the laboratory where the material was analyzed and is usually ready in seven days.
What are the risks of the procedure?
Complications related to colonoscopy can result from the preparation of the colon, sedation, the exam itself, or complementary procedures performed. The preparation can cause gastric intolerance which will reflect in nausea, vomiting, and abdominal distension. As the preparation induces diarrhea, dehydration and an imbalance of the body’s electrolytes can occur. Complications related to sedation range from irritation of the punctured vein (phlebitis) to more serious situations with low blood pressure, bradycardia, respiratory depression, bronchoaspiration, and even cardiac arrest. Intestinal perforation can occur during the introduction of the colonoscope. However, this complication occurs in only about 0.05% of colonoscopies for diagnostic purposes. Resection of polyps can lead to two complications: perforation and hemorrhage. Such events are mainly related to the size of the resected polyps. Perforation can occur with a frequency of 0.03 to 1% of polypectomies and hemorrhage in about 0.02% of procedures, which can happen at the time of polyp resection or even days later.
What should I do after the procedure?
After the exam, you can rest until you are awake and alert enough to be taken home (you cannot drive vehicles). You should plan to continue resting for a few hours after you get home. It is normal to have gas and mild cramps for a few hours after the exam. After resting, you should feel like eating. The diet returns to normal again, but light meals are recommended. Make sure to drink plenty of fluids after the exams. If polyps or other tissue is removed, you may notice a little blood in your stool for a short time. In case of malaise, nausea and vomiting, intestinal bleeding, or severe abdominal pain, the patient should contact the endoscopy service or seek an emergency service with the exam report in hand.
Residência em Endoscopia Digestiva no Hospital das Clínicas da USP (HCFMUSP)
Residência em Gastroenterologia no Hospital Universitário da UFSC
Presidente da SOBED / SC na gestão 2018-2020
Médico da clínica Endogastro em Florianópolis e ProGastro em Joinville