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Colonoscopy

A colonoscopy is a technique to look directly at the lining of the large bowel (colon) to try to find out what is causing your problems.

The colonoscope is a thin, flexible tube with a bright light on the end. This tube is passed through the back passage and into your bowel.

It allows samples of tissue (a biopsy) or removal of small warty growths (polyp) to be taken painlessly for testing later.

What are the risks associated with this procedure?

  • Bloating and abdominal discomfort are not unusual for a few hours
  • Perforation of the bowel (a hole in the bowel) is an uncommon complication. The risk is increased if a polyp needs to be removed (on average 1 in 300 cases). This may require an operation to repair the damage.
  • Bleeding can complicate polyp removal (severe bleeding occurs in less than 1 in 300 cases). Rarely, this may require a blood transfusion and less commonly surgery.
  • Using sedation can cause breathing complications in up to 1 in 200 procedures, which usually are not serious.
  • No test is 100% accurate and abnormalities may be missed, including cancers

The person doing the test will discuss any questions you may have about the risks.

A video recording and /or photographs may be taken for your records.

What are the benefits of this procedure?

Your doctor has referred you for a colonoscopy in order to investigate some symptoms you have been having, such as a change in bowel habit, rectal bleeding, or to review a problem they may have found before, like polyps or colitis. This will benefit you by providing a clear diagnosis.

During the procedure the doctor will also be able to remove small polyps. Like all tests, this is not guaranteed to demonstrate all abnormalities and on rare occasions conditions are not identified.

What are the alternatives to this procedure?

Colonoscopy is the only method that allows direct inspection of the bowel wall. In less than 10% of cases the whole large bowel may not be seen and may require another test. Other forms of examinations include barium enema, Computer tomography (CT) scan and a newer technique called virtual colonoscopy.

Pre-assessment appointment

Patients attending for a Colonoscopy procedure are seen by a pre assessment nurse prior to the date of their procedure. At this appointment the pre assessment nurse takes information from you and advises you how to prepare for the procedure. He/she will also give you the bowel cleansing medication and discuss your consent. At this appointment you are able to ask questions concerning the procedure, your medications and so forth. Failure to attend this appointment may mean your Colonoscopy procedure is cancelled.

If you have a Colostomy and your back passage (rectum) has been removed, the investigation will be carried out through your stoma; therefore you will need to change your pouch to a drainable pouch whilst on Bowel Prep to help manage the watery output coming through your stoma and you will only need to empty your pouch as it fills up. You might need to keep your drainable pouch on for a day or two after procedure before changing back to your closed pouch.

If you have a back passage (rectum) and a colostomy, depending on the indication for the test, you may have the rectum, stoma, or both examined at the same appointment. Your pre – assessment nurse will be able to advise you further. You may also require an enema (small tube of liquid) to be administered in order to empty the rectum. The pre assessment nurse will discuss this with you.

If you have an ileostomy and you require a camera test through your stoma, you will not be required to take bowel prep.

Please ensure you bring spare stoma devices with you to the test, and any other

If you have any queries following your pre assessment appointment, please contact the unit where you will be having your procedure.

Seven days before your appointment please stop all iron tablets.

If you take medication for your blood pressure, please make sure you take this as usual prior to your procedure with small sips of water (at least 2 hours before). After this you should not drink anything further.

Please remember to bring all of your medications with you on the day

Please also bring with you a bag to keep your personal items in for whilst you are here.

Medication

Please do not take any other medication for one hour before starting bowel cleaning with picolax or movi-prep. If you do, the medicine might be flushed out of your system before it can work. Apart from this you may continue to take your usual medication with clear fluids.

Please bring any medication you are currently taking (including sprays and inhalers) with you to your appointment. If you are taking a number of tablets, please bring in your repeat prescription sheet.

If you are either a diabetic, on warfarin, clopidogrel, rivaroxaban, apixaban, or dabigatran (inform the pre assessment nurse). For those patients who do not have an appointment with the pre-assessment nurse, please contact the unit, as your appointment may need to be altered and you may need additional information) please contact the unit for further information.

If you suffer with Sleep Apnoea and usually use a CPAP machine at night, please bring this with you on the day of your procedure.

When you arrive at the Hospital

Please report to the reception desk where a receptionist will check your details and direct you to the waiting area.

Please be aware the appointment time you have been given, will be your admission time. Your procedure will be carried out as near to this time as possible however on occasions due to emergency patients being seen, this may be delayed.

  • Please do not bring any valuables to the hospital
  • Please do not wear any nail varnish, lipstick or jewellery
  • Please bring a dressing gown and slippers for your comfort
  • Please bring a contact number of a relative or friend

A nurse will then explain the procedure to you, to make sure you understand the benefits, and possible risks as detailed here. The staff will want you to be as relaxed as possible for the test, and will not mind answering your questions.

You will be taken to a room and asked to change into a hospital gown, your slippers and dressing gown.

Just before the procedure you will also see the person who will be performing the test and they will ask you to confirm your agreement and they will also sign your consent form.

If you need the help of an interpreter to understand any of this information, or on the day of the procedure, please contact the unit where you will be having the test, as soon as possible.

Please note, relatives/friends or children should not be used as interpreters when you are required to sign your consent form. You should contact the Endoscopy Unit who will arrange for an interpreter to be present.

During the Test

In the examination room you will be made comfortable on the couch. You will be asked to lie on your left side. The back passage will be examined using a finger before the colonoscope is inserted. When the colonoscope is inserted, air is passed into the bowel to inflate it (distend), which helps to give a clearer view. This may give you wind pains which should not last too long. You may feel the sensation of wanting to go to the toilet, but as the bowel is empty this is unlikely. You may pass wind and although this is embarrassing for you remember staff understand what is causing the wind. Some discomfort is usual through stretching of the bowel but this will be kept to a minimum. You may be asked to roll over onto your front or back which is normal practice.

The procedure may take 20 to 40 minutes or more, especially if a polyp has to be removed.

If a polyp or biopsy needs to be taken, a wire snare or forceps do this. This is not painful. The base of the polyp is usually cauterised (burnt) in the process. This reduces the risk of bleeding. A sample of the bowel wall may be taken to help with your diagnosis. This is not painful.

After the test

Recovery time can vary following this procedure depending on any treatment you may have been given. As a general rule you will be recovered for at least one to two hours following your procedure.

Going Home

The wind pains and bloating should have settled. It is important you tell the nurse if they have not, or if they are becoming worse. If you have had sedation it is essential that a responsible adult comes to pick you up from the unit and accompanies you home by car or taxi. Public transport is not suitable and it is advisable you have the following day off work. Please note the unit closes at 6pm. Your relative/friend should arrive no later than 5.30pm to collect you.

When you arrive home it is important to rest quietly for the remainder of the day with someone to look after you for 24 hours.

For the first 24 hours following sedation do not:

  • drive a car
  • drink alcohol
  • take sleeping tablets
  • operate any machinery or electrical items – even a kettle
  • sign any legally binding documents
  • work at heights (including climbing ladders or onto chairs)

Sedation can impair your reflexes and judgement. The effects of the sedation will have worn off by the next day and most patients will be able to resume normal activities.

If you have been given entonox on its own for pain relief, you will have the option to drive home following your procedure however, it is important that you feel capable before considering whether to drive. You must wait at least 30 minutes after use before driving or using any machines. This will be discussed with you at your pre assessment visit.

When will I know the results?

The nurse who has been looking after you will be able to give you a brief outline of the test results, before discharge from the unit.

If a biopsy or polyp has been removed, the laboratory results will take longer, about 4 – 6 weeks. The nurse will advise you to discuss the details of the results and any necessary treatment with your GP or hospital specialist.

If you are a bowel cancer screening patient, your specialist nurse will contact you following your procedure, to arrange a follow up appointment to see them in clinic to be given your results.

You will be given written instructions on your procedure and your aftercare and a copy of your report. If you have any questions about the test, please contact the unit where you will be having the colonoscopy.

Last reviewed: 22 April 2024