What is a sigmoidoscopy?
A sigmoidoscopy is an endoscopic procedure where a long, thin, flexible tube or "scope" is placed into the rectum and advanced through the lower third of the colon. As such, the exam is limited in that not all of the colon will be seen. The scope has a light and a camera on the end of it which allows the physician to examine the lining of the colon. A sigmoidoscopy may be performed to diagnose the cause of gastrointestinal symptoms such as diarrhea, bleeding, abdominal pain, or abnormal x-ray results. A sigmoidoscopy may also be performed on an asymptomatic patient at age 50 to screen for colon cancer and polyps
What should I expect the day before the procedure?
You will receive instructions from your doctor regarding the necessary bowel preparation to get you ready for your exam. Most patients will be on clear liquids all day, the day before the exam. There are several different options for laxatives to clean out the colon. It is very important to follow the instructions given to you by your doctor. There will also be additional instructions regarding your medications. In most cases, your medications will be continued as usual. However, in certain circumstances, especially in patients on blood thinners (i.e. coumadin, warfarin, plavix, aspirin, antiinflammatories) and in diabetics, special instructions will be given. Patients will be instructed not to take anything by mouth after midnight except for medications.
What happens on the day of the procedure?
You will be asked to arrive at the Endoscopy center 1 to 1.5 hours before your exam. This is to allow time to fill out paper work and prepare for the exam. You will be asked to change into a medical gown. In most cases, an intravenous (IV) catheter will be not be started since in general, sedation is not administered with this exam. You may be connected to equipment which will allow the doctor and staff to monitor your heart rate, blood pressure, pulse, electrocardiogram, breathing and oxygen level during and after the exam.
Once in the exam room, you will be asked to lie on your left side on the stretcher. The physician will perform a rectal exam. The sigmoidoscope will then be gently inserted into the rectum. The scope will be carefully advanced through the sigmoid colon. A small amount of air is injected through the scope into the colon to help the physician see. Any fluid remaining in the colon after the preparation can be washed and suctioned out through the scope. Depending on the findings of the exam, several things can be done at the time of the procedure including biopsies, removal of polyps, and control of bleeding. At the end of the procedure, as much of the air and remaining fluid as possible is suctioned out of the colon through the scope. Depending on the findings, the exam takes approximately 5-15 minutes.
Because sedation is not generally used, after the exam is complete the patient is allowed to change back into their clothes and is discharged from the Endoscopy unit. If sedation is not used, you will be allowed to drive and perform your usual activities. Most patients are able to eat and drink normally after their discharge from the Endoscopy unit, however, specific instructions regarding activity, eating, and medications will be given to the patient prior to discharge.
When will I get my results?
After the exam, the doctor and/or nurse will go over the findings of the procedure with you. The patient will also go home with a typed report. The patient will be informed of any biopsy results usually within one week.
What are the risks of the exam?
In general, sigmoidoscopy is a very safe procedure. Overall, complications occur in less than 1% of patients. Most complications are not life-threatening, however, if a complication occurs, it may require hospitalization and surgery. Prior to the exam, a consent form will be reviewed with the patient by the nursing staff. Should any questions or concerns arise, these can be discussed with your physician prior to beginning the procedure.
Bleeding can occur with biopsies and the removal of polyps. Again, significant bleeding which might require a blood transfusion or hospitalization is very uncommon. However, bleeding can occur at the time of the exam or out to 2 weeks after the exam if a polyp is removed.
Perforation or puncture of the colon can occur. This may be recognized at the time of the exam, or it may not be apparent until later in the day. In most cases, a perforation will require a surgery and hospitalization. This is an uncommon complication, even when polyps are removed.
It is very important that the patient contact the doctor's office immediately if symptoms arise after the procedure such as worsening abdominal pain, bleeding, or fever.
Like any other test, a sigmoidoscopy is not perfect. There is a small, accepted risk that abnormalities including polyps and cancers can be missed at the time of the exam. It is important to continue to follow-up with your doctors as instructed and inform them of any new or persistent symptoms.
What are alternatives to a sigmoidoscopy?
To an extent, the alternatives to the exam will depend on the reason for needing to undergo the sigmoidoscopy in the first place. There are different x-rays which can evaluate the colon including barium enema, virtual CT scan. These are however only diagnostic exams. Treatment of abnormalities will require a sigmoidoscopy, colonoscopy or surgery.