Colonoscopy

Colonoscopy is a diagnostic procedure during which the doctor uses a colonoscope to look inside the large intestine (colon) and rectum. During the procedure, the doctor inserts a medical instrument called a colonoscope into the rectum. 

The colonoscope is a thin and flexible tube that has a tiny camera and light at the end of it which helps the doctor view the inside of the entire rectum. This test can detect irritation and swelling of the tissue, ulcers, polyps, and cancer.

Colonoscopy is performed to investigate the symptoms and detect colorectal diseases and conditions.

The American College of Surgeons estimates that around 90% of tumours and polyps can be detected through colonoscopy.

A colonoscopy can help the doctor find the cause of the following condition:-

• Chronic diarrhoea
• Bleeding from anus
• Chronic constipation
• Pain in the abdomen
• Unexplained weight loss
• Changes in bowel activity

The doctor can also use this diagnostic procedure as a screening tool for colon polyps and cancer. 

Screening is testing for diseases when you have no symptoms. It can help the doctor detect colorectal cancer before the symptoms develop. Early detection can improve treatment outcomes.

Like any other diagnostic procedure, colonoscopy also pose a few possible risks that may include the following:-

• A tear (perforation) in the colon or rectum wall
• Adverse reaction to the anaesthesia used during the exam
• Bleeding from the site where a tissue sample was taken for biopsy or a polyp or other abnormal tissue was removed.

Usually, after discussing the possible risks of colonoscopy with you, the doctor asks you to sign a consent form authorising the procedure.

The doctor wants to know about any special condition that you might have such as:-

• Pregnancy
• Kidney diseases
• Lung conditions
• Heart conditions
• Allergies to medications

Apart from all this, you must also tell your doctor if you have diabetes, blood pressure, hypertension, or you take certain drugs that could affect blood clotting.

The doctor might need to adjust these medications before you undergo the procedure to minimise the risk of complications.

To increase the chances of a successful colonoscopy, you must keep a few things in mind before undergoing the procedure. 

The very first thing that you must ensure is that you have a clean colon, which means you need to restrict your diet 24 hours before the procedure.

You are required to avoid solid foods. However, the doctor may say yes to having liquids such as:-

1. Water
2. Broth
3. Coffee
4. Sport drinks

The next step in the preparation is to empty your bowel and the doctor may ask you to take care of this in one of the several ways, including:-

• Drink prescribed laxative
• Supplement the laxative with a series of enemas

The doctor might ask you to do it the night before your procedure or the night before and the morning of the procedure. Make sure to follow the doctor’s guidelines. 

Once all these measures are taken properly, do bring someone to take you home post-procedure. Since you will be sedated during the procedure, it would not be safe for you to drive for at least 8 hours afterwards.

During the colonoscopy, the doctor asks you to lie on the exam table. Then the doctor gives you sedatives through an intravenous (IV) in your arm which will make you sleep during the entire procedure.

After that, the doctor puts a medical instrument called a colonoscope into the rectum. A colonoscope has a camera and light on the tip of it which helps the doctor to see the lining of the colon and detect if there is any problem.

The colonoscope also has a tube that allows the doctor to pump air and inflate the colon. This gives a better view of the colon and its lining. The doctor may also use a small snare in the colonoscope to take samples of the colon for biopsy or polyps.

After completion of the procedure, the sedative takes around an hour to wear off until then you have to wait at the hospital. The doctor usually doesn’t advise you to drive for the next 24 hours, until the effect of the sedative fades completely. 

If the doctor removes tissue or a polyp during a biopsy, the doctor sends it to the laboratory for testing. The doctor informs you about the same once the results are ready, which normally takes a few days