Procedures

COLONOSCOPY
A Guide to the Procedure

WHAT IS A COLONOSCOPY?

Colonoscopy is a procedure that enables examination of the lining of the colon (large bowel) using a thin flexible tube with a video camera, lens and light source at its end (colonoscope), which is advanced slowly from the rectum, around the colon.

WHY IS A COLONOSCOPY DONE?

• Rectal bleeding
• Iron deficiency anaemia.
• Abdominal pain and alteration in bowel habit
• The presence of colorectal cancer risk factors
• Clarification of barium enema findings
• Positive Faecal occult test.
• Indication for repeat colonoscopy
• Patients with previous bowel polyps or cancer
• Surveillance of inflammatory bowel disease.
• Patients with a family history of bowel cancer or polyps in first degree relatives.

WHAT PREPARATION IS REQUIRED?

The colon must be completely clean for the procedure to be accurate and complete. You will be given detailed instructions regarding the dietary restrictions to be followed and the cleansing routine to be used. In general, preparation consists of either consumption of a large volume of a special cleansing solution or several days of clear liquids and laxatives prior to the examination. Follow the instructions carefully.

WHAT ABOUT MY CURRENT MEDICATIONS?

Most medications may be continued as usual but some medications can interfere with bowel preparation or the examination. It is therefore best to inform your doctor of your current medications, as well as any allergies you may have to medications. Aspirin, arthritis medications, anticoagulants, insulin, and iron products are examples of medications whose use should be discussed with your doctor prior to the examination, It is essential that you alert your doctor if you require antibiotics prior to undergoing dental procedures, since you may need antibiotics prior to your colonoscopy as well.

Possible medication adjustments: Before the test, be sure to discuss with the doctor whether you should adjust any of your usual medications before the procedure, any drug allergies you may have, and whether you have any major conditions such as a heart or lung condition, that might require special attention during the procedure.

WHAT CAN BE EXPECTED DURING THE COLONOSCOPY?

Colonoscopy is usually well tolerated. There may be a feeling of pressure or bloating during the procedure. Your doctor will give you a medication through a vein which will put you to sleep and you will not feel or remember anything. You will be lying on your left side, or on your back, while the colonoscope is advanced slowly through the large intestine. As the colonoscope is slowly withdrawn, the lining is again carefully examined.

The procedure usually takes between 15 and 30 minutes. In some cases, passage of the colonoscope through the entire colon to its junction with the small intestine cannot be achieved. The doctor will decide if the limited examination is sufficient or if other examinations are necessary.

WHAT IF THE COLONOSCOPY SHOWS SOMETHING ABNORMAL?

If your doctor thinks that an area of the bowel needs to be evaluated in greater detail, a biopsy (tissue sample of the colon lining) may be taken using tiny forceps. These specimens are submitted to the pathology laboratory for analysis. If colonoscopy is being performed to identify sites of bleeding, the areas of bleeding may be controlled through the colonoscope by injecting certain medications. If polyps are found, they are generally removed. Remember, biopsies are taken for many reasons and do not necessarily mean the cancer is suspected.

WHAT ARE POLYPS AND WHY ARE THEY REMOVED?

Polyps are abnormal growths from the lining of the colon. They vary in size from a tiny dot to several centimetres. The majority of polyps are benign (non-cancerous) but we cannot always tell a benign polyp from a malignant (cancerous) polyp by its outer appearance alone. For this reason, removed polyps are sent for analysis by a pathologist. Removal of colon polyps is an important means of preventing colorectal cancer.

HOW ARE POLYPS REMOVED?

Tiny polyps may be totally destroyed by fulguration (burning) but larger polyps are removed by a technique called snare polypectomy. The doctor passes a wire loop (snare) through the colonoscope and severs the attachment of the polyp from the intestinal wall by means of an electrical current. You should feel no pain during the polypectomy. There is a small risk that removing a polyp will cause bleeding or result in a burn to the wall of the colon (perforation), which could require emergency surgery.

WHAT HAPPENS AFTER THE COLONOSCOPY?

After colonoscopy, your doctor will explain the results to you. If you have been given medications during the procedure, you will be observed until most of the effects of the sedation have worn off (usually 1-2 hours).

You may have some cramping or bloating because of the air introduced into the colon during the examination. This should disappear quickly with the passage of flatus (gas).

You will need to arrange to have someone accompany you home from the examination.

Do not:

• Drive a car
• Work machinery
• Consume alcohol
• Sign legal documents
• Make important decisions

Until the following day.

WHAT ARE THE POSSIBLE COMPLICATIONS OF COLONOSCOPY?

The only possible complication from colonoscopy is a perforation or tear through the bowel which could require surgery. Bleeding may occur from the site of a biopsy or polypectomy. This is usually minor and should stop on its own, or it can be controlled through the colonoscope. Rarely, blood transfusions or surgery may be required.

Potential risks include a reaction to the sedatives/anaesthetic used, and complications from heart or lung disease. Localised irritation of the vein where the medication was injected may cause a tender lump lasting for several weeks but this will go away eventually. Applying heat packs or hot, moist towels may help relieve discomfort. Although complications after colonoscopy are uncommon, it is important for you to recognise early signs of any possible complications: severe abdominal pain, fevers and chills, or rectal bleeding (more than half a cup). Bleeding can occur for several days after polypectomy.

If you have any problems after discharge, contact your doctor or nearest emergency department for assistance.

If any of your questions have not been answered here, please feel free to discuss them with the endoscopy nurse or your doctor before the procedure begins.