Colonoscopy

Your doctor may recommend this test if you have symptoms such as rectal bleeding, a persistent change in bowel habit, ongoing diarrhoea, unexplained abdominal pain, or unexplained anaemia.

A colonoscopy can help to identify the cause of these symptoms. It is also used to screen for bowel cancer, particularly if you have a family history or are within the recommended screening age group.

If small growths called polyps are found, they can usually be removed during the procedure. Removing polyps reduces the risk of developing into cancer in the future. Small samples of tissue, known as biopsies, can also be taken to help clarify a diagnosis. Taking biopsies is painless.

Good preparation is essential to ensure that the bowel is clean and that the examination is accurate. If the bowel is not adequately prepared, small abnormalities can be missed and the test may need to be repeated.

You will usually be advised to follow a low-fibre diet for several days before the procedure. This will involve avoiding wholegrains, seeds, nuts, and fruit and vegetables with skins. The day before the test, you will normally be asked to take a laxative to empty your bowels. This causes frequent loose stools for several hours. It is important to stay near a toilet during this time and to drink plenty of clear fluids to avoid dehydration.

You will receive clear written instructions about when to stop eating and drinking, and when to take the bowel preparation. If you take regular medication, particularly blood thinners, diabetes medication, or iron tablets, you should discuss this with your doctor in advance as adjustments may be needed.

A colonoscopy usually takes between 30 and 45 minutes, although this can vary.

When you arrive, a nurse will check your details and explain the procedure again. You will be asked to change into a hospital gown. A small cannula may be placed in a vein in your arm so that medication can be given.

The colonoscope is gently inserted through the back passage and carefully guided around the colon. Carbon dioxide gas is introduced to gently inflate the bowel so the lining can be seen clearly. You may feel a sensation of fullness, pressure, or cramping as the scope moves around bends in the bowel. 

Sedation and pain relief are usually offered to make you more comfortable. Some people choose light sedation and remain relaxed but awake, while others prefer deeper sedation. The procedure itself is not usually painful, but it can be uncomfortable at times.

If polyps are found, they can often be removed straight away using tiny instruments passed through the colonoscope. If biopsies are required, these are taken using small forceps through the scope.

You will be monitored in a recovery area until the effects of sedation begin to wear off. Most people can go home within one to two hours. If you have had sedation, you will need someone to take you home and you should not drive, operate machinery, sign important documents, or drink alcohol for 24 hours.

It is common to experience some bloating or mild abdominal discomfort for a few hours afterwards due to the gas used during the test. Passing wind can help relieve this. A small amount of rectal bleeding may occur, especially if biopsies were taken or polyps removed. This is usually minor and settles on its own.

You should seek urgent medical advice if you develop severe abdominal pain, persistent heavy bleeding, a high temperature, or feel unwell after the procedure.

In many cases, your doctor will discuss the initial findings with you before you go home. If biopsies have been taken, the results usually take several days and arrangements will be made to communicate these to you once available. Your doctor will then explain whether any further treatment or follow-up is needed.