What to expect from a colonoscopy

Written by: Dr Debasis Majumdar
Published: | Updated: 26/11/2020
Edited by: Robert Smith

If you notice any unusual symptoms involving the change in your bowel habit, it will be a good idea to have your bowel inspected with a colonoscopy.


We spoke to expert gastroenterologist, Dr Debasis Majumdar, who let us know how your families medical history can determine whether you should have a colonoscopy, we found out what this procedure is exactly, how to prepare and whether it's painful.

What is a colonoscopy?

It's basically a camera test to check the inside of your large bowels. We insert a camera with a light, and lens source introduced through the back passage into the large bowel. We even have the ability to get into the terminal part of the small bowel and can inspect the entire colon. We can take a biopsy and view pathologies. We take biopsies to be inspected. If we find any warty overgrowths or colonic polyps then during the tests, we can remove the polyps.

Why is a colonoscopy done usually?

A colonoscopy is usually done due to various symptoms which may include unusual bowel habits, this may be someone with onset diarrhoea, constipation, significant pain, blood with stool. Sometimes there's a strong family history of bowel cancer that makes you have more of a chance of getting it. In this subgroup, we would carry out colonoscopy to check their bowel even if they don't have symptoms.

What does a colonoscopy detect? (aside from colon cancer)

Colonoscopy can detect any abnormality that can happen in the lining of the bowel and polyps. It can help highlight characteristics of inflammatory bowel disease, and can find other causes of diarrhoea, weight loss, pain in the abdomen. It can detect benign conditions. It can detect causes of rectal bleeding and pain, like haemorrhoids, anal fissure.

How can I prepare for the procedure?

You would need to get good guidance, generally we request patients to take a day off before the test, the day before the tests its recommended to take a day off from work. This is due to how they would need to have laxatives to clear their bowels. Patients shouldn't eat any fibre as it leaves a lot of residue; we ask patients not to eat anything from midnight the day before and recommend they drink fluids to avoid dehydration. We recommend change in medication such as blood thinners at times.

After the procedure, we observe the patient, and we let them go with a report and tell them to eat a meal that is easily digestible because they would have fasted for more than 12 hours. The day after they can resume their normal lifestyle habits.

We also give instructions with caution to look for any bleeding. If it's overt and continuous, then there is a number they can ring to get in contact, it's also recommended to ring if there is any unusual pain in the abdomen. In the case of continuous bleeding, it's important patients go to their nearest accident and emergency department.

Does the procedure hurt?

It's not painful, but one would feel a bit of a bloated sensation and mild discomfort. Because the large bowel is used only for one way traffic, the bowel can go into cramp mode with a colonoscopy.

Are there any pain relief options?

One can have the procedure being completely conscious. In those cases, we offer Entonox or 'laughing gas’ to breathe in. It's totally patient-controlled medication, so they can adjust the amount needed to according to their discomfort.

Another option is to use an intravenous painkiller, one that doesn't knock them off, it makes people feel relaxed and also controls the cramps and the bloaty pain.

For more information on having a colonoscopy, we recommend booking an appointment with a leading gastroenterologist such as Dr Debasis Majumdar. Visit his Top Doctors profile today for more information.

By Dr Debasis Majumdar

Dr Debasis Majumdar is a leading gastroenterologist in Croydon who specialises in colon cancer, colonic polyps, endoscopy, colonoscopy, pancreato-biliary medicine, ERCP and endosonography.

In 1997 Dr Majumdar graduated with his medical degree from the University of Calcutta, India. He also obtained his MD from the university in 2001. In 2018 he was awarded his MD from Durham University on the completion of his research on polyp surveillance in the NHS bowel cancer screening programme.

Dr Majumdar has a passion for training in endoscopic and teaches in national endoscopic training courses. He is a Joint Advisory Group (JAG) accredited trainer for OGD, colonoscopy, ERCP and EUS.

Dr Majumdar has extensively published papers in peer-reviewed journals including the Journal of the Royal College of Physicians of Edinburgh, Journal of Gastroenterology and Hepatology and the Journal of the Association of Physicians of India. He has held presentations both nationally and internationally.

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