Colonoscopy is an examination of
the large intestine using a long thin flexible video endoscope. (sedation will
be given by the anaesthetist during the procedure)
Direct visualization of : polyps,
inflammation of bowel wall, abnormal blood vessels (angiodysplasia).
can be taken for histology.
Most polyps can be removed and treated at the same
there are haemorhoids, these can be banded at the same time. Banding is good at
reducing bleeding from haemorrhoids and can reduce the size of prolapsing
haemorrhoids. If there are already skin tags with associated haemorrhoids,
these will not go away with banding. (The rubber bands are applied more than an
inch inside the anal canal to reduce the pain and as such will not get rid of
the external haemorrhoids) After the banding, there can be discomfort, feeling
of fullness/wanting to go to the toilet(like a severe constipation) and
sometimes pain if the haemorrhoids are large. A local anaesthetic nerve block
and Procosedyl suppository/Lignocaine gel is usually given to reduce the pain/discomfort.
The bands usually fall off withing 2 weeks. Avoid sitting on the toilet and
straining for too long after the banding. You need to take a high fibre diet
and keep yours stools soft in the long term to reduce the risks of the
Perforation - Hole in bowel(1 in
1000; risk incresased if larger polyp removed, adhesions/hysterectomy or cancer
present): if so will need surgery
Serious bleeding from bowel(or
more rarely bleeding from spleen where colon is attached) (1 in 1000) : may
need blood transfusion or an operation. Minor bleeding from trauma to
reactions; aspiration/pneumonia; heart attack/stroke; death(1 in 10000)
because of looping/angulation of bowel- will then need another method of
investigation to view the rest of the colon eg Contrast enema or CT colonscopy
Incomplete view - Polyps may be
missed / covered by faeculent fluid / faeces / mucosal fold (1-5%)
Other Investigations As Alternatives to Colonoscopy
1. Contrast (Barium) enema or CT colonoscopy - Advantages: not as invasive, less risks of perforation, shorter waiting time for investigation (especially in public hospitals) Disadvantages: poorer visualization of smaller polyps/mucosal abnormality, exposure to radiation, no views of rectum(need another more limited scope (sigmodoscopy) to look at rectum)
2. Faecal occult blood test - to screen for polyps and bowel cancer.
3. Faecal colon cancer DNA test - this will be more common in future as technology improves and cost comes down
4. Capsule endoscopy - good for imaging the small bowel, especially with persistent bleeding or anaemia despite normal gastroscopy and colonoscopy
BOWEL PREP INSTRUCTIONS FOR COLONOSCOPY
A colonoscopy enables the doctor
to see the inside lining of your large bowel(colon). In order to get a good
view, it is important that the bowel is thoroughly emptied and clean on the
inside - otherwise the bowel wall on the inside may be partially covered by
BEFORE THE COLONOSCOPY
1 week before colonscopy -
Stop these medications - aspirin,
clopidrogel(eg. Plavix, Iscover), dipyridamole(eg Asasantin, Persantin). (These
medications increase the risk of bleeding especially if a biopsy needs to be
performed during the colonoscopy) It is important that this is discussed first
with your usual doctor and surgeon performing the colonoscopy.
5 days before colonoscopy - If you are taking warfarin(Coumadin,
Marevan), this is usually stopped then. Again it is important to discuss this
with your usual doctor and your surgeon. For some low-risk patients on
warfarin, that is all that needs to be done. For high-risk patients(risk of stopping the
anticoagulant), daily injections with low-molecular weight heparin may need to
2 days before colonoscopy -
Take only low-residue foods eg white
bread, white rice, eggs, potato without the skin. Do NOT eat vegetables, fruits
or anything high in fibre(avoid any food with seeds in it!)
1 day before colonoscopy -
DRINK CLEAR FLUIDS ONLY after
light dinner. Clear fluids include - water, black tea WITHOUT milk, clear fruit
juices without pulps, clear soup, soft drinks, mineral water and cordial.
Take the 2 sachets of PICOPREP or Picolax(this can be
purchased from a pharmacy) :
1. Mix the sachets of Picoprep
with a glass of warm water
2. Take the first sachet of Picoprep
12 hours before the procedure and the second sachet 6 hours before the procedure. Eg 8pm and midnight for an 8am procedure
REMEMBER to continue drinking at
least a glass of water/clear fluids every hour.
You may have clear fluids UP TO 4
HOURS BEFORE the procedure.
Avoid coffee and alcohol as these
can cause you to lose more fluids especially from your urine.
Day of Procedure
An anaesthetist will put in a drip and give sedation during the procedure.
After the colonoscopy, one will need to be observed in recovery.
Post-procedure : One may feel bloated/pass more flatus/pass small amount of blood(esp if biopsies taken)
It is important to make arrangements ahead of time
for someone to drive you home. Do not drive or operate any machinery or
sign any legal documents on the day of the colonoscopy/anaesthesia.
Immediately after the procedure,
you may feel some addominal discomfort/cramps or bloating. You may also feel
like passsing wind.(This is due to the air gently insufflated into your bowel
during the colonoscopy)
A complete report will be
forwarded to your doctor.
Should you have any bleeding,
abdominal pain, black tarry stools or fever within 2 weeks after the procedure,
you should contact your doctor immediately.