Colonoscopy

A colonoscopy is a procedure that allows your consultant to see the lining of your colon (large intestine or bowel) in order to detect any abnormalities (inflammation, ulcers, polyps, etc.).

The procedure can take anywhere from twenty to sixty minutes, depending on what is found during the procedure. A soft, flexible tube (a colonoscope), which is about the width of an index finger, will be gently inserted into the anus and passed into the rectum and the colon. A light sensitive chip is built into the end of the colonoscope. This will allow your consultant to view images of your bowel on a video monitor.

Polyps are small growths inside the colon. Removal of these polyps is called a polypectomy. In most cases, you will receive your colonoscopy diagnosis and return home the same day, without admission into hospital.

A colonoscopy is a valuable tool to help diagnose and treat many different conditions. These include inflammatory bowel disease (IBD), such as Crohn's disease or ulcerative colitis — colonic polyps and bowel cancer.

A colonoscopy can be used as a routine screening test in people aged 50 years and older (with no symptoms) to prevent the development of bowel cancer.

Some of the most common reasons to perform a colonoscopy are to:

• Investigate changes in bowel habits or rectal bleeding.
• Assess patients with known polyps or previous polyp removal.
• Evaluate patients with inflammatory bowel disease.
• Remove polyps or investigate abnormalities found on other imaging tests.
• Screen for bowel cancer.

There is now an alternative to traditional colonoscopy that is much less invasive and does not require sedation. This is called a virtual colonoscopy, otherwise known as a CT pneumocolon, which is an examination that uses images of the inside of the bowel and colon obtained by means of computerised tomography instead of images taken by the colonoscopy camera. This may be followed up by a colonoscopy if any issues are found.

During a colonoscopy, you will be lying on your side or your back. You may be given a sedative and an analgesic to help you relax and to reduce any pain. After inserting the colonoscope into your bowel, your consultant will gently pump some carbon dioxide gas or water inside. This opens the large bowel so the lining of the colon can be clearly seen.

A colonoscopy usually takes 15 to 30 minutes; however, the whole appointment may take around two hours. This time will allow you to prepare and recover from the procedure.

Cleansing the colon before a colonoscopy is called bowel preparation or a 'bowel prep'. A bowel prep will usually include the use of a strong laxative to completely empty your colon of stool. This will help to produce more reliable colonoscopy results. So, it is important that you follow the specific bowel prep instructions that will be provided to you in a personalised kit before the procedure.

These instructions will include information about when to start fasting before the procedure, eating a low-fibre diet a couple of days before the procedure, taking clear-liquid diet on the day before and the day of the colonoscopy and the use of strong laxatives to take the day before your appointment.

Before this gastrointestinal procedure, tell your doctor about any medications you're taking, including over-the-counter drugs or supplements. These might include blood thinners, vitamins that contain iron, and certain diabetes medications. You may be advised to stop taking some of them.

Like any medical procedure, you may experience some unwanted side effects after having a colonoscopy. These are usually temporary and you may have some mild cramping or bloating from the gas that was placed into the colon. You may also notice some bleeding from your back passage if you have had biopsies or polyps removed.

If you were given a sedative, this will affect your reflexes for the rest of the day. So, it is important that you arrange to have someone to drive you home after the procedure. Do not drive or operate machinery until the next day.

Your consultant will explain the results to you after your procedure and they may give you a date for a follow-up appointment.

Risks of a colonoscopy are rare, and occur in fewer than 0.1% of cases, as it is a routine procedure. Possible risks or complications include abdominal discomfort, dehydration secondary to the bowel prep.

The most serious complication following colonoscopy is a perforation of the bowel, which may lead to emergency surgery; the risk of this complication is less than 1 in 1000.

If the specialist feels that a more accurate evaluation is necessary, they will obtain a biopsy of the lining of the bowel for analysis. If polyps are found during the procedure, these can be removed straight away.