Endoscopic Tests
Colonoscopy (Endoscopy of the Large Bowel)
What is a colonoscopy?
A colonoscopy is an examination in which a doctor inserts a flexible endoscope through the anus to examine the entire large bowel and, where possible, the final part of the small intestine.
It is the most accurate examination of the large bowel. It can detect colorectal cancer at an early stage, identify and remove precancerous polyps, diagnose inflammatory bowel disease and detect other conditions affecting the large bowel.
During the examination, the doctor may:
- take biopsies (tissue samples);
- remove polyps;
- stop bleeding;
- perform other therapeutic endoscopic procedures.
When is a colonoscopy recommended?
Your doctor may recommend the examination if:
- you have had a positive faecal occult blood test;
- you have rectal bleeding;
- you have persistent diarrhoea or constipation;
- you have unexplained anaemia;
- you experience abdominal pain;
- inflammatory bowel disease is suspected;
- you require surveillance after the removal of polyps or surgery on the large bowel;
- you are undergoing colorectal cancer screening.
How should you prepare for the examination?
Diet
2–3 days before the examination:
Follow a low-fibre diet.
Avoid:
- wholegrain products;
- grains and cereals;
- nuts;
- seeds;
- sweetcorn;
- mushrooms;
- fruit and vegetables with skins or seeds;
- red or purple foods.
The Day Before the Examination
- Usually, only a light breakfast is permitted unless your doctor has instructed you otherwise.
- Afterwards, consume only clear liquids:
- water;
- clear tea;
- clear broth;
- clear juice without pulp.
Do not consume dairy products or opaque drinks.
Bowel-Cleansing Solution
The bowel is cleansed using a special laxative solution prescribed by your doctor.
The best results are achieved using a split-dose preparation:
- part of the solution is taken on the evening before the examination;
- the remaining part is taken on the day of the examination.
Unless your doctor has instructed you otherwise, it is generally recommended that you begin taking the second part of the solution approximately 6 hours before the examination and finish it 4 hours before the procedure.
It is important to drink the entire prescribed amount of the solution and to consume sufficient additional clear liquids.
In some cases, your doctor may recommend taking simeticone, which reduces foam in the bowel and improves visibility of the bowel lining.
Medicines
Make sure you tell your doctor about all medicines you take before the examination.
It is particularly important to discuss:
- anticoagulant medicines;
- aspirin and other antiplatelet medicines;
- medicines for diabetes;
- iron supplements.
Iron supplements are usually stopped 5 days before the examination.
Do not stop taking diabetes medicines or medicines that affect blood clotting on your own. Only adjust them as instructed by your doctor.
How is a colonoscopy performed?
At many healthcare facilities in Lithuania, colonoscopy is performed under intravenous sedation or short general anaesthesia. However, this may vary depending on the healthcare facility and your individual circumstances.
During the examination:
- a flexible endoscope is inserted through the anus;
- air or carbon dioxide (CO₂) is introduced into the bowel to provide a clearer view of the lining;
- biopsies may be taken or polyps removed where necessary.
The procedure usually takes 20–45 minutes, although it may take longer if therapeutic interventions are performed.
Is the examination painful?
During sedation, most patients do not feel the examination or experience only minimal discomfort.
If sedation is not used, you may experience abdominal pressure, bloating or temporary cramps.
Possible Complications
Colonoscopy is a safe examination.
In rare cases, the following complications may occur:
- bleeding, particularly after the removal of polyps;
- damage to the bowel wall (perforation);
- complications associated with sedation or general anaesthesia.
The vast majority of complications can be treated successfully.
After the Examination
If you were given sedation or general anaesthesia:
- do not drive on the same day;
- do not operate machinery;
- do not sign important documents;
- you should travel home with an accompanying adult.
After the examination, you may experience:
- abdominal bloating;
- cramping;
- increased gas.
These symptoms usually resolve on their own within a few hours.
If polyps were removed, your doctor will provide individual instructions regarding physical activity, diet and medicines. They will also explain when and how you will receive the histology results.
When should you seek immediate medical attention?
Contact a healthcare facility immediately or call the emergency services if you develop any of the following after the colonoscopy:
- severe or worsening abdominal pain;
- heavy rectal bleeding;
- fever;
- chills;
- repeated vomiting;
- marked weakness, fainting or dizziness.
Frequently Asked Questions
Is taking a biopsy painful?
No. The lining of the bowel does not contain pain receptors, so you will not feel the biopsy being taken.
Are all detected polyps removed?
Usually, yes. If it is technically possible and safe, polyps are removed during the same procedure.
Why do I feel bloated after the examination?
Air or carbon dioxide is introduced into the bowel during the examination, which may cause temporary bloating or cramps.
When can I eat?
Unless your doctor has instructed you otherwise, you can usually eat shortly after the procedure. A special diet may be recommended after more extensive endoscopic interventions.
Can I go to work after the examination?
If you were given sedation or general anaesthesia, you should rest and avoid driving for the remainder of the day.