Flexible Sigmoidoscopy

Overview

A flexible sigmoidoscopy uses the same thin, flexible camera tube used in a full colonoscopy — but instead of travelling all the way around your large bowel, Mr Nguyen only guides it through the lower portion. That means he can look carefully at your rectum (the very end of your bowel), your sigmoid colon (the S-shaped section sitting just above the rectum), and your descending colon (the left side of your large bowel). These are the areas most likely to explain symptoms like rectal bleeding, mucus, or discomfort around the back passage.

Because only part of the bowel is examined, you do not need the full bowel-cleansing preparation that comes with a colonoscopy — no large volumes of liquid to drink the night before. Instead, a simple phosphate enema (a small amount of fluid gently given into your back passage to empty just the lower bowel) is done by the nursing staff on the day. You will be given sedation so you are comfortable and relaxed throughout, and from start to finish the whole thing takes around 10–15 minutes. It is a short procedure, but it gives Mr Nguyen very clear, detailed information about exactly what is going on in your lower bowel.

Who needs this procedure?

Mr Nguyen may recommend a flexible sigmoidoscopy for you if any of the following sound familiar:

• You have noticed rectal bleeding (blood on the toilet paper or in the bowl) and the most likely cause is somewhere in the lower bowel
• You have been told you may have proctitis or distal colitis — that is, inflammation of the lining of your rectum or the lower part of your colon — and Mr Nguyen wants to see it directly and assess how it is responding to treatment
• You have had bowel surgery and need ongoing check-ups — for example, to look at the join (called an anastomosis) that was made inside your rectum and make sure it has healed well
• You had a rectal polyp (a small growth on the bowel lining) removed in the past and it is time for a follow-up check to make sure nothing new has appeared
• You are experiencing symptoms around your back passage — discharge, pressure, discomfort, or mucus — that need to be properly assessed
• A focused look at the lower bowel is the right first step, and Mr Nguyen will decide from there whether a full colonoscopy (which looks at the entire large bowel) is also warranted

Benefits

• Much simpler preparation than you might expect — a short enema given by the nursing staff on the day is all you need. No large bowel-cleansing drinks, no fasting from the evening before, no disrupted day prior to the procedure
• You will be comfortable throughout — sedation is given through a small drip in your hand before we begin, so you are relaxed and drowsy during the examination. Most people have little or no memory of the procedure itself, and many are surprised by how easy it was
• It is quick — the camera examination itself typically takes 10–15 minutes. You will then rest in the day-stay unit while the sedation wears off, and you are usually ready to go home within 30–60 minutes of waking up
• The risks are very low — lower than with a full colonoscopy, because only the lower portion of the bowel is examined. Serious complications are uncommon
• Problems can often be addressed in the same sitting — if Mr Nguyen spots something that needs attention, such as a small polyp (a growth on the bowel lining) or an area of inflammation, he can take a biopsy (a tiny tissue sample sent to the laboratory) or perform a polypectomy (removal of a small polyp) during the same procedure, without needing to bring you back
• It gives clear, accurate answers — a direct look at the lining of your rectum and lower colon gives Mr Nguyen precise information about what is causing your symptoms, rather than guessing

Risks & considerations

Serious complications from a flexible sigmoidoscopy are uncommon — this is considered one of the safest endoscopic procedures. That said, it is worth understanding what can occasionally happen, so you can make an informed decision and know what to look out for afterwards.

• Perforation (a small tear in the bowel wall) — this is very rare, occurring in roughly 1 in every 10,000 flexible sigmoidoscopies. If it did happen, it would be identified quickly and treated promptly. To put it in perspective: the risk is far lower than for a full colonoscopy, because only the lower bowel is examined.
• Bleeding after a biopsy or polyp removal — if a small tissue sample (biopsy) was taken or a polyp removed, there is a small chance of some minor bleeding. In the vast majority of cases this settles on its own without any treatment needed. The risk is less than 1 in 100.
• The upper bowel is not examined — a flexible sigmoidoscopy only looks at the lower portion of your large bowel. If your symptoms could be coming from higher up, or if something is found that warrants a fuller look, Mr Nguyen may recommend a complete colonoscopy as a next step. This is not a failure — it is simply gathering more information if it is needed.
• Wind discomfort and bloating — a small amount of air is gently introduced into the bowel during the examination to open it up and give a clear view. It is very common to feel some cramping, bloating, or an urge to pass wind for an hour or two afterwards. This is harmless and settles on its own; a gentle walk around can help it pass more quickly.

Before your procedure, Mr Nguyen will sit with you and go through your individual situation — what he expects to find, what he is looking for, and what you should know beforehand. Please bring any questions you have to that conversation. There is no such thing as a silly question when it comes to understanding your own care.

Before the procedure

• A phosphate enema (a small amount of liquid gently introduced into your back passage to empty the lower bowel) will be given by the nursing staff 1–2 hours before your procedure at the endoscopy unit. You do not need to do anything special at home the evening before — the preparation for this procedure really is that straightforward.
• Please arrange for a responsible adult — a family member or friend — to drive you home afterwards and stay with you for a few hours. You cannot drive yourself or take public transport alone after sedation, even if you feel fine. This is a firm safety requirement, not a suggestion.
• Wear comfortable, loose clothing on the day — it makes changing in and out of a hospital gown much easier, and you will feel more relaxed.

On the day

It helps to know exactly what is going to happen, so here it is, step by step:

• When you arrive at the endoscopy unit, the nursing team will welcome you, check you in, and explain what is about to happen. They will then administer the phosphate enema — it is quick and the staff do it every single day. You are in calm, experienced hands from the moment you walk in.
• Once you are ready, the sedation (given through a small drip in your hand or arm) will make you feel drowsy and relaxed within a minute or two. Most people are surprised by how gentle this part feels.
• You will be asked to lie on your left side on the procedure table. Mr Nguyen will then gently guide the thin, flexible camera through your back passage and slowly advance it through your rectum and into the left side of your colon, inspecting the lining carefully as he goes.
• If he finds anything that needs closer attention — such as an inflamed area or a small polyp (a tiny growth on the bowel lining) — he may take a biopsy (a tiny tissue sample, sent to the laboratory for analysis). Under sedation, you will not feel this at all.
• The examination itself takes around 10–15 minutes. When it is done, Mr Nguyen will come and have a brief chat with you about what he saw. You will also be given a written endoscopy report to take home, and a copy goes directly to your referring doctor.
• You will then rest comfortably in the day-stay unit for 30–60 minutes while the sedation fully wears off, and once the nursing team is satisfied that you are alert and well, you are free to go home.

Recovery & aftercare

• The day of the procedure: Once the sedation has worn off and the nursing team is happy you are alert and steady, you can head home — usually within 30–60 minutes of waking up. You can eat and drink normally from that point. Most people feel perfectly well within a few hours.
• Bloating and wind: It is very common to feel some bloating or an urge to pass wind for an hour or two after the procedure — this comes from the small amount of air used during the examination to open up the bowel for a clear view. It settles on its own, and a gentle walk around the house can help it move along more quickly. This is normal and nothing to worry about.
• If a biopsy was taken: You do not need to change your diet or restrict your activities in any way. Simply carry on as normal. The biopsy results take a couple of weeks to come back from the laboratory.
• Your biopsy results: If tissue samples were taken, the histology report (a pathologist's examination of the tissue under a microscope) is typically ready within 1–2 weeks. Mr Nguyen will contact you to go through the results within 2–6 weeks of your procedure. For most endoscopy patients this is done by phone or telehealth at no charge. If the results need a more detailed conversation, or if further management is needed, you will be asked to come into the rooms — and Mr Nguyen's team will reach out to you promptly if anything needs earlier attention.
• Next steps: Depending on what Mr Nguyen finds, a full colonoscopy (a camera examination of the entire large bowel, from rectum to the far end) may also be recommended. If so, he will explain clearly why that additional step is useful for you specifically — it is not a cause for alarm, just a more complete picture.
• Your follow-up review: Mr Nguyen schedules a review within 2–6 weeks of your procedure. For endoscopy patients this is typically a phone or telehealth call at no additional charge. If you need to be seen in person — for example, to plan further treatment — a standard consultation fee applies.

Related patient guides

These guides go into more depth on topics that are often on patients' minds around the time of this procedure. They are written in plain language — feel free to read them before your appointment, or afterwards if you want to understand your results better.