Colonoscopy is a medical procedure that allows a specialist gastroenterologist to examine the inside of the colon (large intestine) and ileum (final segment of small intestine).


The procedure is performed using a soft, thin, flexible tube called a colonoscope. The colonoscope has a high-definition camera at the tip along with a bright light source, which allows your specialist to obtain detailed images of the inner lining of bowels. It is the test of choice for evaluation of the structure and anatomy of the colon.


What are the reasons to have a colonoscopy performed?

There are three main categories of reasons for having a colonoscopy performed.


  1. Evaluation of digestive symptoms

    • Red blood in the stool

    • Diarrhoea

    • Constipation

    • Weight loss

    • Abdominal pain

    • Positive faecal occult blood test (FOBT), which detects microscopic blood in the stool

    • Suspected blood loss from the GI tract, due to anaemia or iron deficiency

    • Weight loss

    • Bloating

  2. For the early detection and prevention of colon (bowel) cancer in those at increased risk

    • Previous colonic polyps

    • Family history of colon cancer

    • Following successful cure of colon cancer

  3. For evaluation or treatment of known conditions affecting the intestines

    • Crohn’s disease

    • Ulcerative colitis

    • Angiodysplasia of colon

    • Diverticular disease

How do I prepare for a colonoscopy?

Colonoscopy does require some preparation in order to ‘clean out’ the bowels. Without doing so, it is impossible for your specialist to navigate the colon and get an accurate view. For this reason, it is imperative that you follow the bowel preparation instructions carefully, as the better the quality of the bowel preparation, the higher the quality of examination your specialist is able to perform.


You will receive a detailed instruction sheet outlining the preparation instructions, but in essence:

  • Two days prior to the procedure, you must start consuming only a ‘White Diet’ which consists of a number of easy to process white foods. Not all white foods are allowed

  • From 5pm the evening before the procedure, you must stop eating completely, and only consume clear fluids thereafter

  • From the evening before, you will commence drinking the bowel preparation solution. The timing varies based on the timing of your procedure the next day. Often, the last dose of bowel preparation is taken on the morning of the procedure. 

  • Stop drinking clear fluids 2 hours before the procedure and completely fast from this point


With regards to your regular medications, in general these should as usual up until the procedure. There are a few exceptions:

  • Stop iron supplements for one week prior to the colonoscopy

  • Stop all fibre supplements (e.g. Metamucil, Benefiber) two days prior to the procedure

  • Notify your specialist if you are taking blood thinners (e.g. Aspirin, Plavix (clopidogrel), Warfarin, Xarelto, Eliquis etc.). These may or may not need to be stopped beforehand, but this decision needs to be made on a case by case basis by your specialist.


What happens during a colonoscopy?

Once you are comfortably asleep, your specialist will pass the scope through your anus (back passage) and into the colon. The scope is then gently further advanced all the way to the right side of the colon, and often, into the ileum (final segment of small intestine). The lining of the bowel is washed with water sprayed from the tip of the scope, to ensure that every part can be clearly seen. Minor remaining debris or residue can be suctioned through the scope. The entire bowel lining is closely inspected for any abnormalities. Modern colonoscopes have accessories including a special light filter and optical magnification which can be turned on to allow a highly detailed image to be obtained. If necessary, biopsies can be taken through a channel in the endoscope. If abnormalities are noted, various therapeutic interventions can be performed at the same time (see below). The colonoscopy ordinarily takes no more than 30 minutes in total.


What are colon (bowel) polyps and why are they important

Colonic polyps are small growths in the lining of the colon (large intestine). Polyps are important because they are the precursor to bowel cancer (colorectal cancer).


Bowel cancer is second leading cause of cancer deaths in Australia. There are over 15,000 cases of bowel cancer in Australia each year. 


As with any cancer, prevention is better than cure, and screening colonoscopy remains the most powerful method to reduce the risk of developing bowel cancer. Colonoscopy reduces the risk of developing cancer by identifying benign but pre-cancerous polyps, and removing them before they have a chance to turn into cancer. The process of removing such polyps is termed polypectomy.


Once a polyp is found and removed, you remain at risk of developing new polyps in the future. In this situation, your specialist will usually recommend a repeat colonoscopy in the future, with the interval determined by characteristics of the polyp.


What is a polypectomy?

Polypectomy refers to the removal of colonic polyps during a colonoscopy. The majority of polyps are removed using a wire loop called a snare, which is passed through the colonoscope and carefully positioned around the polyp. The removed polyp tissue can then be captured, collected and sent to the lab for analysis under the microscope.


Will I feel anything during my colonoscopy? Does it hurt?

In short, the answer is no. You may have heard stories of people having very unpleasant or painful colonoscopies, but this is no longer the case with the methods used in our practice. All patients having their colonoscopy performed by Dr Santosh will have a specialist anaesthetist present, who will ensure they are comfortable for the procedure. The anaesthesia used provides deep sedation without the need for general anaesthesia, so is safer. Practically, this means that you will be deeply asleep while the procedure is performed, and will not feel or remember anything. 


What should I expect after the colonoscopy?

You will normally wake up within 30 minutes of completion of the procedure. A nurse will be monitoring your vital signs and when he or she assesses that you are ready, you will be moved to a chair and given a drink and light meal. 


Once you have woken up, your specialist will speak to you after the procedure and explain the findings. You may be required to contact us to arrange a follow up appointment in order to review your symptoms and/or biopsy results, which can take a few days (or longer) to be analysed in the lab.


You should arrange for a friend or family member to pick you up and accompany you home. As subtle effects of the anaesthesia can linger, you should not drive, operate heavy machinery or work for the rest of the day. You can return to your normal duties the following day. In the past, many patients would experience some abdominal pain following the procedure. However nowadays with change in the type of gas that is used to perform the procedure, most patients feel entirely normal from a physical point of view immediately following the procedure. If mild cramps or bloating occur, they should subside within the next 24 hours. If biopsies have been taken or polyps removed, you may notice a few drops of blood in the first couple of bowel motions. If you experience more severe symptoms after returning home, such as vomiting, severe abdominal pain, heavy bleeding (more than half a cup of blood) or fever, then contact us or attend the Emergency department.


Is colonoscopy safe?

Colonoscopy is deemed a low-risk procedure and is very safe when performed by an experienced gastroenterologist. Risks are higher when polypectomy is performed, but using modern polypectomy techniques, the process has become very safe especially for polyps under 10mm in size. For some larger polyps, there can be slightly higher risks such as bleeding or even perforation of the colon, but thankfully these risks remain uncommon. Even if such complications occur, they can often by treated and controlled using instruments passed through the colonoscope. 


Can upper GI endoscopy be performed along with my colonoscopy?

Yes, an upper endoscopy can be performed at the same time as colonoscopy. No extra preparation is required, and they can be performed under the same anaesthesia. Speak to your specialist to see whether or not you need both procedures performed.


Who performs colonoscopy procedures in Sydney?

Colonoscopy is best performed by a specialist gastroenterologist, who has years of training in both diagnostic and therapeutic colonoscopy, and is wholly devoted to performing endoscopic procedures. Further, only a gastroenterologist has expertise in the medical treatment of conditions that may be diagnosed during a colonoscopy. In Sydney, contact Dr Santosh Sanagapalli to have your procedure performed by a trusted gastroenterologist with expertise in this procedure. 

Trusted Gastroenterologist based at St Vincent's Hospital campus, Darlinghurst, Sydney.

Expert care in all aspects of gastrointestinal health with subspecialty expertise in disorders of the oesophagus.

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