What to expect after a colonoscopy?

Written by: Dr John Martin
Edited by: Lisa Heffernan

Have you been told that you need a colonoscopy? A colonoscopy allows your doctor to take a look at your colon and rectum to find cancer or polyps. It is a safe examination with very few risks. Dr John Martin tells us a bit more about what to expect after a colonoscopy and what recovery looks like.

What will happen after the procedure?

Patients may be sedated during a colonoscopy and often require some time to recover from the medication. After a colonoscopy, the patient will be taken to a recovery area for a period of observation. Here they can relax and will be given something to eat and drink.


How long is the recovery?

If a patient has had no sedation, recovery is almost instantaneous. However, with sedation recovery time may be longer. Although the patient will often feel very little of the side effects of the medication, on leaving the hospital, they must not drive, drink alcohol, operate heavy machinery, or sign any legal documents within the subsequent 24 hours, after which the drug will have left the body.


What symptoms can I expect after the procedure?

Patients may experience abdominal bloating and gas after a colonoscopy. Their bowel movements may take two to three days to return to normal.


Is there any pain after the procedure?

Some patients may get mild cramps after the procedure, but these usually settle within an hour. It is very rare to develop severe pain, but if this occurs, they should return to the hospital to seek medical advice.


Is bleeding after a colonoscopy normal?

Bleeding will not occur after a diagnostic colonoscopy. If the colonoscopy was accompanied by another procedure, such as a biopsy or the removal of polyps, some patients may see a small amount of bleeding, but this is not a cause for concern.


Heavy bleeding is rare but may be the sign of a problem. If this occurs, the patient should seek medical help.


What are the possible complications after the procedure?

Very rarely patients have a reaction to the sedation medication. Elderly patients or those with lung problems are at greater risk and your doctor will assess this risk prior to the procedure and will reduce the levels of medication appropriately.


Heavy bleeding, needing a blood transfusion, may occur in patients who have had a polyp removed, although this is in only one out of 2,400 patients. Perforation, or damage to the bowel, may also happen, with about one in 1,700 patients having this complication.


Are there alternatives?

Patients who don’t want to be sedated may have a CT colonoscopy, an examination that involves taking a special X-ray scan of the colon. As with a colonoscopy, the colon needs to be emptied beforehand, and if a polyp or cancer is found a colonoscopy will be required to remove it or take a sample.


Although slightly uncomfortable, a colonoscopy can effectively diagnose colorectal cancer at an early stage. The examination can also find and remove polyps, thus preventing the development of cancer. Complications after the procedure are extremely rare, but if you feel unwell, experience severe pain or significant bleeding after a colonoscopy, call your doctor immediately.


For more information or to get in touch with Dr John Martin, please visit his profile.

By Dr John Martin

Dr John Martin graduated from Cambridge University and King’s College Hospital, London in 1990 and completed his gastroenterology training within North West London.  He is a highly-experienced gastroenterologist and endoscopist based in London and holds an NHS Consultant post at Imperial College (ICL).  He is an expert in colorectal cancer screening, therapeutic and diagnostic colonoscopy and has 25 years experience of managing all aspects of gastroenterology including abdominal pain or discomfort, reflux disease, diarrhoea and constipation, rectal bleeding, Irritable Bowel Syndrome, Crohn’s Disease and Ulcerative Colitis.

Dr Martin teaches colonoscopy both within the  NHS Trust and also at national screening centres. He is a bowel cancer screening accredited colonoscopist and an examiner for BCSP colonoscopy accreditation.

Dr Martin is Director of the West London Bowel Cancer Screening Centre, he is the national advisor to Public Health England on endoscopy within the Bowel Cancer screening service and chairs the national advisory committee on quality and safety of endoscopy within screening. He forms an integral part of numerous other professional bodies and has been widely published in peer-reviewed journals.

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