A colonoscopy is a specialised procedure primarily used for colorectal cancer screening. It
helps identify and remove polyps, or abnormal growths that can develop into cancer over time.
Additionally, the procedure aids in diagnosing inflammatory bowel diseases (IBD), rectal
bleeding, chronic diarrhoea, and unexplained weight loss.
The procedure involves a thin, flexible tube with a tiny camera inserted into the rectum,
providing a clear view of the colon’s interior.
A colonoscopy is a procedure that examines the inside of the large intestine, including the colon,
rectum, and anus. It serves both preventive and diagnostic purposes, allowing doctors to detect,
assess, and sometimes treat various bowel conditions. Whether for symptom investigation or routine
screening, a colonoscopy remains the gold standard for ensuring long-term digestive health.
In Singapore, regular colorectal screenings are recommended starting from the age of 45–50. This is
especially crucial for individuals with a personal or family history of colorectal cancer, polyps,
and other bowel conditions.
Proper preparation is essential for a successful colonoscopy, ensuring a clear view of the colon for accurate diagnosis. Preparation for the procedure may include:
- Bowel cleansing, which involves the use of a prescribed laxative
- Consuming a low-fibre diet in the days leading up to the procedure
- Consuming only clear liquids such as water, broth, and tea (without milk) a day before the procedure
- Fasting (no food or drink) 6–8 hours before the procedure
- Temporarily adjusting any medications as directed by the specialist
Strict adherence to these instructions is crucial. Incomplete preparation may require the procedure to be repeated or rescheduled.
A colonoscopy is a relatively simple procedure completed within a single visit. Here is what you can expect before, during, and after the procedure:
Before the colonoscopy begins, a small intravenous (IV) line will be inserted into a
vein in your arm or hand. This IV line allows for the administration of sedation or
anaesthesia to ensure your comfort during the procedure. The type of sedation or
anaesthesia will be determined by your doctor based on your individual needs and
medical history.
Sedation options include:
- Conscious Sedation: This option keeps you relaxed and drowsy but allows you to remain responsive to instructions.
- Deep Sedation: This option induces a deeper level of sedation, leaving you drowsy and unaware of the procedure.
- General Anaesthesia: In some cases, general anaesthesia may be used, which will render you completely unconscious during the procedure.
Once the sedation or anaesthesia takes effect, your vital signs, including heart rate, blood pressure, and oxygen levels, will be closely monitored to ensure your safety.
As you lie on your side, the doctor will carefully insert a lubricated colonoscope
into your rectum. This flexible, tube-like instrument with a tiny camera, is
carefully guided through the colon to identify abnormalities, such as inflammation,
unusual tissue growths, or early signs of disease.
If any irregularities are found, specialised instruments can be passed through the
scope’s channel to take a biopsy for further testing. Additionally, if polyps are
detected, they can often be removed immediately, reducing the risk of future
complications.
Once the scope reaches the end of the colon, near the junction of the small
intestine, the doctor will slowly withdraw it, performing a second examination to
ensure nothing is missed. The entire process typically lasts between 20 and 40
minutes, depending on the complexity of the findings and any necessary
interventions.
Following the colonoscopy, you will be transferred to a recovery area where medical
staff will closely monitor your vital signs as the effects of sedation gradually
subside. You may experience drowsiness, slight disorientation, or mild abdominal
cramping due to residual air in the colon.
Once you are alert and stable, your doctor will discuss preliminary findings. This
may include whether any polyps were removed or biopsies were taken. While some
initial results may be available immediately, more detailed results, such as biopsy
reports, typically require further analysis and will be shared with you within a few
days.
Due to the potential effects of sedation, it is crucial to have a responsible adult
accompany you home. Most patients can resume normal activities and their regular
diet the following day unless otherwise advised by their doctor.
Following a colonoscopy, it is important to follow the post-procedure care guidelines provided
by your doctor. This typically involves beginning with a light diet, such as clear liquids and
broth, gradually reintroducing regular foods. Most patients can resume normal activities within
24 hours, although strenuous exercise should be avoided. Your doctor will schedule a follow-up
appointment to discuss the results of your colonoscopy.
For your health and safety, contact your doctor immediately if you experience:
- Severe abdominal pain or cramping
- Rectal bleeding (more than a small amount of blood)
- High fever or chills
- Difficulty breathing
Prompt medical intervention can help prevent further complications.