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What Is A Colonoscopy? 6 Crucial Facts To Understand [As Of 2023]

Dr QM Leong
Dr QM Leong

A colonoscopy is a medical procedure that involves the examination of the digestive system, particularly the colon lining and rectum. This procedure is done to detect bowel irregularities and determine possible colorectal or colon cancer symptoms.

A colonoscopy is also performed to identify symptoms such as bleeding or the presence of colon polyps.

1. What Happens During A Colonoscopy?

What Happens During A Colonoscopy

A colonoscopy starts with a doctor inserting a colonoscope or a tiny flexible tube with a scope (camera) attached to the end. 

This tube passes through the rectum and into the colon (the largest part of the large intestine), allowing the doctor to view the patient’s colon and detect any abnormalities or pathological changes.

Aside from examination, the doctor may also conduct a colonoscopy to gather a tissue sample (also known as a biopsy) or remove an abnormal tissue.

Gastrointestinal symptoms, colorectal cancer, abdominal pain, and other changes in bowel habits are also determined through a colonoscopy.

A colonoscopy procedure will usually culminate after 30 to 60 minutes. However, doctors may recommend that patients allocate at least 2 hours before and after a colonoscopy to prepare and recover.

Patients may have a few hesitations before undergoing a colonoscopy. However, the doctor will reassure them that this is a safe procedure with minimal-to-no complications.

First, the doctor will administer anaesthesia, sedatives, or pain medicine intravenously. Healthcare professionals will monitor your vital signs and ensure you’re comfortable throughout the colonoscopy.

Then, the doctor performs air or carbon dioxide insufflation, which allows them a better view of the patient’s bowels. 

Insufflation refers to the process of inflating the colon. It’s an indispensable step in a colonoscopy, allowing the doctor to pass the scope through the organ without injuring the patient’s gastrointestinal wall.

During a colonoscopy, the doctor may need to perform a biopsy to remove polyps or abnormal tissue. 

2. How To Prepare For A Colonoscopy?

Patients due for a colonoscopy will be provided ample time to prepare for the procedure. Their doctors will require them to undergo bowel preparation to ensure success and prevent repeat colonoscopies.

Bowel preparation before a colonoscopy generally involves changing a patient’s dietary habits. These changes prevent the accumulation of undigested food in the bowel, which may make it difficult for the doctor to visualise the colon and rectum.

These are some dietary instructions that a colorectal doctor may prescribe a patient before undergoing a colonoscopy:

  • Eat light meals – A day before the colonoscopy, the patient will need to eat light meals for breakfast and lunch (no dinner). They may also need to adopt a liquid-only diet.
  • Ingest laxatives – The patient may also be required to take laxatives a day before or on the morning of the colonoscopy.
  • Drink clear liquids – The patient needs to drink only broth, water, tea, and black coffee prior to a colonoscopy.
  • Take an enema – An enema refers to the insertion of liquid into the rectum, which allows the body to remove any residual waste in the bowels. The liquid is often a water-based solution that contains a small dose of stool softener.
  • Follow a low-fibre diet – A low-fibre or low-residue diet means eating foods easily digested and absorbed in your body. This results in less stool passage. Low-fibre food includes white bread, biscuits, white rice, cornflakes, and skinless potatoes.

Talk to your doctor if you are taking any medications or supplements before undergoing a colonoscopy. The doctor may require you to stop taking them temporarily or to adjust your dosage accordingly.

Tell your doctor if you have other health conditions requiring you to take blood-thinning medicines, medication for diabetes, heart problems, or iron-containing medication.

These medicines can potentially increase your risk of bleeding during the colonoscopy, or they may react to the sedatives or anaesthesia administered by your doctor.

3. What Happens After A Colonoscopy?

After a colonoscopy, your doctor will direct you to a recovery room where you will rest until the anaesthesia or sedatives wear off after a few hours.How long you’ll stay will depend on the sedation and the kind of pain medicine you were given.

It is normal to feel mild cramping, bloating, gas, and discomfort after the procedure, but these should go away quickly or within 24 hours after the colonoscopy.

Follow the doctor’s instructions carefully regarding colonoscopy recovery. For instance, you will be advised by a healthcare provider on when you can drink and eat solid food after the procedure.

Suppose you’ve undergone colorectal cancer screening wherein your doctor performs a biopsy. In that case, you will be informed of when the results will be available and whether or not you require further testing.

If your doctor removes polyps or abnormal tissue (during a colon cancer diagnosis), you will be informed of any temporary dietary changes you need to follow.

Don’t be alarmed if you discover small traces of blood during your first bowel movement after the colonoscopy, as it is normal. However, it’s advised to consult with your doctor immediately if you find blood clots in your stool.

4. Why Is A Colonoscopy Necessary?

Why Is A Colonoscopy Necessary

A colonoscopy is the primary method by which doctors examine potential colon cancer symptoms such as:

  • Rectal bleeding
  • Constipation
  • Stomach pain
  • Diarrhoea
  • Tumours
  • Ulcerations
  • Inflammation
  • Colon polyps

A colonoscopy detects colorectal cancer in its early stages before the symptoms can develop. A colonoscopy screening is ultimately crucial, as it helps improve treatment outcomes for the patient.

Risk Factors For Developing Colon Cancer

The chances of getting colorectal cancer or colon cancer increase as you age. Some risk factors include:

  • Inflammatory bowel diseases (e.g. ulcerative colitis or Crohn’s disease
  • Presence of a genetic syndrome (e.g. familial adenomatous polyposis or hereditary non-polyposis colorectal cancer)

5. When Should I Undergo A Colonoscopy?

Anyone can take a colonoscopy screening, no matter their age. But it’s recommended you take one, especially if you have risk factors which can increase your likelihood of developing colorectal cancer.

Nevertheless, regular screening is recommended for individuals aged 45 and above. Adults aged between 50 and 75 are also recommended to undergo a colonoscopy once every 10 years. This frequency may increase depending on other lifestyle and health factors.

6. What Happens If The Doctor Finds Abnormal Tissue During A Colonoscopy?

Abnormal Tissue During A Colonoscopy

If your doctor finds abnormal tissue, they will take a sample by removing the polyps and sending them to a laboratory for further analysis. This allows them to determine whether the polyps are benign (non-cancerous) or malignant (cancerous).

The doctor may also recommend a repeat colonoscopy, especially after removing polyps and other abnormal tissue.

Conclusion About What Is Colonoscopy

A colonoscopy is the primary screening method by which doctors diagnose the presence of abnormal tissue growth or colon cancer. 

It’s a safe procedure involving inserting a flexible tube (attached to a scope) to assess the colon and rectum.

Get in touch with the best colorectal surgeon in Singapore, Dr QM Leong for more information. He specialises in advanced colorectal and general surgery. 

His other services include cyst and anal fistula removal, gallbladder surgery, hernia surgery, hemorrhoids treatment, and diagnoses of other gastrointestinal issues in Singapore.

Frequently Asked Questions About
What Is Colonoscopy

The cost of a colonoscopy in Singapore can range between $800 and $2,600.

A colonoscopy uses an elongated tube with a scope to examine your digestive system. Meanwhile, a virtual colonoscopy (CT colonography) utilises a CT scan, allowing your doctor to view the cross-sections of your abdominal organs.

No, most patients don’t experience any pain during a colonoscopy.

You may need to wait two to three days before having a bowel movement after a colonoscopy. This is because your colon has been completely emptied before the procedure.

Yes. MediSave can be used for a screening colonoscopy, subject to the TOSP withdrawal limit and an additional $300 daily for day surgery fees.

Yes. Other alternatives for screening colon cancers include:

  • Stool tests
  • Flexible sigmoidoscopy
  • Virtual colonoscopy

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