A colonoscopy may be advised if you have symptoms such as bleeding from the lower bowel, diarrhoea, pains in the lower abdomen, for investigation of anaemia or a strong family history of bowel cancer.
A colonoscopy is often normal, but a normal result is still useful to exclude certain conditions.
The colon needs to be empty so that I can get a clear view. You will be instructed on how to take a special diet and very powerful laxatives (usually Movicol or occasionally KleenPrep) either the day or morning before the test. WKG will provide written instructions when booking the colonoscopy.
A colonoscopy usually takes about 20-30 minutes but expect to be in hospital for 3-4 hours to allow time for a nurse-led assessment on arrival and for time to recover following the procedure.
Colonoscopy is usually done as a day case. It is a routine test which is commonly done. You will usually be given a sedative to help you to relax. This is usually given by an injection into a vein in the back of your hand. The sedative can make you drowsy but it does not ‘put you to sleep’. It is not a general anaesthetic.
You will be asked to put on a gown or shorts that open at the back. While you’re resting on your left side, I will gently examine your back passage with a gloved finger and then carefully insert the colonoscope into your rectum. Lubricating jelly will be used to make this as easy as possible.
Air is then usually pumped through the colonoscope into your colon to make it expand and to make the bowel wall easier to see. This may cause a feeling of pressure, bloating, or cramping during the procedure. It is normal if you get an urge to go to the toilet or pass wind. The procedure is usually well tolerated but rarely may cause more severe pain or discomfort. I may use more sedation or ask you to change position if this occurs.
A camera lens at the end of the colonoscope sends pictures from the inside of your bowel to a monitor. I will look at these images. If necessary, I will take a biopsy and/or remove any small growths or polyps you have. This is done using special instruments passed inside the colonoscope and shouldn’t cause you any pain.
You will be monitored in the recovery area for 15-30 minutes until the effects of the sedatives start to wear off. Normally you will be offered a drink and a light snack once you are fully awake (about 30-45 minutes after the colonoscopy). You may have some mild cramping or bloating from the air that was placed into the colon during the examination. This should quickly improve with the passage of flatus.
I will come and see you before discharge to inform you of the results and to answer any questions that you may have. I shall write, usually 5-7 days later, with the results of any samples taken during the procedure.
Sedatives will affect your judgment and reflexes for the rest of the day. You should not drive, operate machinery, drink alcohol or make legal decisions for 24 hours after having the sedative. You will need somebody to accompany you home and to stay with you until the effects have fully worn off. Most people are able to resume normal activities after 24 hours.
Most colonoscopies are done without any problem. After the procedure you may have some mild pain and discomfort. You may also have a swollen abdomen. This usually gets better after a few hours and can ease when you pass wind.
If you have had a biopsy or had polyps removed you may have a small amount of bleeding. This usually stops on its own.
Complications during or following colonoscopy are uncommon. Possible complications are listed below:
• A tear in your bowel (perforation) – this can happen during the procedure, but it’s rare occurring in less than 1 in 1000 cases. This can lead to an infection. If you develop a high temperature, severe pain or a swollen abdomen, contact WKG or your GP as it could mean you have an infection.
• Bleeding – this is most likely if you have had polyps removed or a biopsy taken. If you have any heavy bleeding (more than half a cup) or see blood in your faeces, contact WKG or your GP.
• Side effects from sedatives – sedatives can occasionally cause problems with your breathing, blood pressure and heart rate. These are usually short lived and quickly treated during the procedure.
I am able to complete colonoscopy (pass the tip to the first part of the colon called the caecum or into the end of the small intestine or ileum) in over 90% of cases (in line with British Society of Gastroenterology recommendations). Sometimes it’s not possible to complete it due to poor bowel preparation, an impassable narrowing or stricture or rarely, a patient may not tolerate the procedure despite sedation. Under these circumstances the colonoscopy may need to be repeated or an alternative investigation, such as an X-ray (barium enema or CT scanning), may be required.
Studies have shown that colonoscopy performed in a patient with a well-prepared (clean) colon is about 90-95% accurate at detecting small polyps or growths. Therefore, a small growth may not be seen even by the most experienced or skilled colonoscopists. Last, a normal colonoscopy does not exclude the development of cancer within the following 12 months and if you develop new symptoms it is sensible to visit your GP or to let me know directly.