Understanding lower gi endoscopy
Lower gastrointestinal endoscopy examines the rectum and colon using a flexible camera. Colonoscopy aims to examine the whole colon; flexible sigmoidoscopy examines its lower portion.
The choice depends on your symptoms and the clinical question. Biopsies or removal of suitable polyps may be possible, but findings sometimes require another procedure or specialist care.
Colonoscopy examines the rectum and colon, sometimes including the end of the small bowel. Flexible sigmoidoscopy examines a shorter lower segment. Which test is appropriate depends on the clinical question; a shorter test is not an interchangeable substitute for a complete colon examination.
The quality of the view depends heavily on bowel preparation. Residual stool can hide small lesions or make the examination incomplete. The endoscopist may recommend a repeat test, a different investigation or specialist treatment if the view is inadequate or a finding cannot safely be dealt with at that visit.
Types & classification
Examination of the rectum and the length of the colon.
Examination of the rectum and lower colon.
Symptoms & causes
Symptoms to look for
- Rectal bleeding or persistent bowel habit changes
- Unexplained iron-deficiency anaemia
- Symptoms needing assessment for bowel inflammation
Common causes & risk factors
- Investigation of a positive screening test
- Suspected polyps or inflammatory disease
- Follow-up of previous bowel findings
When to see a surgeon
- Have persistent bleeding, altered bowel habits or unexplained weight loss assessed.
- Heavy bleeding, fainting or severe abdominal pain warrants urgent care.
How it is diagnosed
Bleeding, bowel habit changes, anaemia, family history and earlier polyps help determine the test and urgency. Not all rectal bleeding should be assumed to be piles.
Colonoscopy, flexible sigmoidoscopy, stool tests or imaging may be appropriate in different situations. The referral should explain what needs to be assessed and whether the entire colon must be examined.
The lining is inspected and biopsies may be taken for inflammation or other microscopic disease. Suitable polyps may be removed for tissue analysis with consent.
The report should record how far the scope reached, the quality of preparation and findings. Pathology results and these technical details help determine the follow-up interval.
Treatment options
The appropriate option depends on your diagnosis, examination and general health. Your clinician will explain the benefits and risks of the available approaches.
Inspection with or without biopsies helps establish a cause for symptoms or an abnormal screening result. Comfort options depend on the test, your health and preferences.
Suitable polyps can be removed during the examination. Size, shape, site and blood-thinning medicines affect whether removal is safe at the same appointment.
A large or complex polyp may need a separate advanced procedure or surgical assessment. Leaving it for a planned treatment can be safer than attempting removal immediately.
Medication, surveillance, further imaging or surgery may follow. A normal test may still need a clinical review if symptoms continue.
Preparing for treatment
- Follow the prescribed diet and bowel-cleansing schedule exactly.
- Tell the team about kidney or heart disease, diabetes and all medicines.
- Arrange an escort if sedation is planned; ask before changing any regular medicine.
- Confirm the exact diet and bowel-preparation schedule for your booked examination; do not borrow another patient’s instructions.
- Tell the team about kidney or heart disease, constipation, diabetes and any problems completing previous preparation.
- Get a written plan for blood thinners and diabetes medicines. Do not stop or alter them yourself.
- Contact the unit if you cannot tolerate the preparation, have persistent vomiting or are becoming unwell. Severe pain or fainting warrants urgent advice.
The procedure, step by step
- Preparation and safety checksThe team reviews preparation, medical history, consent and the plan for sedation or pain relief. Anticipated biopsies or polyp removal are discussed.
- Insertion of the scopeThe flexible camera enters through the anus, usually with you initially lying on your left side. Position changes may help the examination.
- Inspection of the bowelGas or water is used as appropriate to obtain a clear view. The endoscopist inspects the bowel and documents the extent and quality of the examination.
- Biopsy or treatmentTissue samples or suitable polyp removal may be performed. A finding requiring more complex treatment can be documented for another planned appointment.
- Recovery and instructionsThe team provides the report, medicine restart instructions where needed, warning signs and a plan for pathology results and follow-up.
Recovery timeline
- First few hoursBloating or cramps may occur after the examination. You are observed until discharge criteria are met; sedation requires an escort and the advised supervision.
- First 24 hoursFollow sedation restrictions on driving, alcohol, work, machinery and important decisions. Rehydrate and eat according to the discharge instructions.
- After polyp removalThe team may set additional restrictions or a specific medicine plan. Significant bleeding can be delayed, so retain the contact instructions beyond the day of the test.
- Results and ongoing careAsk when biopsies or polyp results will be available and whether another examination is recommended. Do not assume every patient needs the same repeat interval.
Benefits of this approach
- Direct assessment of the lower bowel
- Can sample tissue and remove appropriate polyps
Risks & possible complications
Every operation carries risk, and you should hear about it before you consent rather than afterwards. These are discussed individually at consultation in the context of your own health.
- Bleeding, including delayed bleeding after polyp removal
- Bowel perforation
- Sedation complications or an incomplete examination
- Bowel preparation can cause dehydration or electrolyte problems in susceptible patients; the prescribed plan should account for your health.
- Small lesions can be missed, especially if preparation is poor; the examination may need to be repeated.
- A polyp may require a separate procedure rather than safe removal at the initial examination.
What affects the cost
- Colonoscopy versus flexible sigmoidoscopy and the preparation required
- Sedation and anaesthetist involvement where needed
- Biopsies, polyp removal, clips or specialist equipment
- Pathology and any repeat or advanced procedure required by the findings