This examination allows the doctor to look directly at the inside of the colon (large bowel) as a screening to detect disease early or find out the cause of symptoms.
Using a flexible fiber optic endoscope and dedicated attachments, the procedure provides a detailed optical view that is captured for future reference and can deliver targeted therapies such as removal of polyps, as well as taking biopsies to investigate abnormalities. Doctors may refer patients who are suspected of suffering from colonic diseases such as cancer, or require investigation for rectal bleeding, occult blood in stool, changes in bowel habit, chronic diarrhoea, constipation or difficulty in defecation, to have this examination.
A colonoscopy is carried out under sedation. The doctor passes a thin flexible fibre optic tube with a bright light at the end through the rectum into the colon allowing a detailed view of the terminal ileum, caecum, sections of the colon, rectum and anus.
Sometimes a small amount of tissue may need to be taken from a particular area for further examination in the laboratory (biopsy). The tissue is removed using tiny forceps passed through the colonoscope. This process may cause a brief tugging sensation.
During the test, photographs or DVD of the colon may be taken.
The large bowel consists of the colon and rectum. This part carries the remains of digested food from the small bowel and gets rid of it as waste (called stool, faeces or bowel motion) through the anus. Refer to the diagram on the left.
Dietary and bowel cleansing guidelines will be provided beforehand by medical staff to prepare the patient for the procedure.
The patient ONLY drinks clear water up to two to three hours before the examination.
Bowel emptying preparation usually consists of either drinking a large amount of a special cleansing drink or clear liquids and special oral laxatives.
Instructions should be followed closely otherwise the examination may fail due to retained faeces.
Inform the doctor of any major medical problems such as diabetes, hypertension, bleeding tendency or if pregnant. Medications should be continued as instructed.
Provide information on any current medications and allergies.
Do not drive to attend the procedure appointment and avoid heavy drinking, smoking or use of sedatives before the procedure.
Seniors and those with difficulty walking should be accompanied by a family member.
The colon must be completely clean for the procedure to be accurate and complete, so be sure to follow the instructions above carefully.
Usual medication should be continued, however, as some drugs may affect the examination, it is important to inform the doctor particularly for:
Aspirin products
Arthritis drugs
Antiplatelet drugs eg. Plavix.
Blood thinners eg. warfarin (anticoagulants)
Insulin
Diabetic tablets
Iron supplements
Any herbal remedies
allergies to drugs
a joint replacement
allergies to x- ray contrast media (dye)
a heart valve replacement
a pacemaker
Those who need to take antibiotics before dental treatment may also need antibiotics before a colonoscopy.
The examination may be performed under general anaesthesia, but more often a light sedation or monitored anaesthesia is used. Prior to the examination, intravenous sedation is given to reduce anxiety and discomfort related to the procedure.
Full consciousness will be maintained during the procedure.
In general, the procedure lasts for 30- 45 min, though this may be prolonged in complex cases.
Minor discomfort including abdominal pain and distension are common.
The bowel may be punctured. This can cause leakage of bowel contents into the abdomen. The risk is higher when polyps are removed, depending how large the polyp is. Bleeding from the bowel following a biopsy or removal of polyps. There may be oozing from where the polyps were removed or damage of large blood vessels.
Cardiopulmonary complications
Infection
Acute intestinal obstruction
Polyps or cancer can be missed. The risks are higher if the bowel is not cleaned properly. It is therefore important that the instructions to clear the bowel are followed precisely before the procedure.
Death due to complications of colonoscopy is extremely rare.
In general, the complication risk is less than 1%1% but it varies depending on medical conditions and the complexity of the diagnostic and therapeutic methods used.
Complication rates are higher in cases that require polypectomy, endoscopic hemostasis, dilatation or stenting. When major complications arise, emergency surgical treatment may be needed.
The procedure may not be able to be completed due to bowel disease or other problems.
For more information please consult the doctor.
Cramping or bloating may occur due to air entering the colon during the examination. This should go away once gas is passed.
Bleeding from the back passage for a few days after the procedure may occur. Heavy bleeding must be reported to the doctor.
The doctor will be usually able to explain visual findings directly following the examination. Nonetheless, if results from biopsies are required, then the doctor will schedule another time to report findings.
If intravenous sedation is used, do not operate heavy machinery or drive for the rest of the day.
Clarify with the doctor the examination results and date of follow up.
Follow the instructions given by the medical staff in completing drug treatment.
Call the doctor within office hours for any discomfort after the procedure.
However, if there are any serious events such as passing of large amount of blood, severe abdominal pain, attend the local Accident and Emergency Department for treatment without delay.
For any queries, please consult our medical staff.
The information provided in this article is for reference only and does not replace professional medical advice. Matilda International Hospital and Matilda Medical Centre shall not be held responsible for any decisions made based on this information.