Ipswich Digestive Health Group

Risks

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Risks of Colonoscopy

Colonoscopy is a very safe procedure for the majority of people. We go to great lengths to try and minimise risks and potential side effects. Below are some of the potential complications which can occur.


Minor temporary changes in bowel habit and wind-type symptoms are common immediately after colonoscopy, and if you have any concerns you should contact your doctor or the hospital without delay.

Risks of Colonoscopy

What are the risks of Colonoscopy?

  • Intolerance to colonic preparation

    After taking the colonoscopy preparation, patients occasionally get abdominal cramping, nausea or vomiting. Rarely dizziness and fainting can occur. Very rarely patients can have palpitations or severe imbalance of body salts-electrolytes. In view of this, a responsible adult must be present in your home during the preparation. It is important that the instructions are followed carefully to minimise the risk of this problem.

  • Reaction to the anaesthetic

    Serious reactions are rare. Complications can include: pain in the arm at the injection site, brusing or infection where the cannula is inserted, nausea and vomiting, altered heart rates, dizziness or fainting, allergic reaction, aspiration of vomit from the stomach into the lungs, heart attack, stroke and death (extremely rare).


    If you have any questions please ask the anaesthetist prior to the procedure.

  • Bleeding

    This is very rare following a standard colonoscopy and biopsy. The risk is increased if a polyp is removed. This occurs in approximately 1:1000 cases but up to 1-3% if very large flat polyps are removed. If bleeding occurs, this may require hospitalisation. Rarely a blood transfusion and operation is required to control the bleeding.


    Patients on anti-platelet/blood-thinning medications need to consult their doctor prior to having their colonoscopy. If these are continued, then polyps may not be able to be removed during the procedure.

  • Perforation

    With a standard colonoscopy in a healthy bowel, without removal of polyps, the risks of perforation are approximately 1:10,000 procedures. The risks can be higher if your bowel is diseased (e.g severe diverticulosis).


    If there is a perforation, this can present with severe pain following the procedure. This life threatening complication will require a prolonged hospital stay and usually an operation with possibly a colostomy bag for two months.

  • Acute diverticulitis can be exacerbated

    A colonoscopy should not be performed within 4 weeks after an attack of diverticulitis.

  • Missing polyps and cancers

    Colonoscopy and polypectomy reduces the risk of cancer but there are still a small percentage of procedures where a significant lesion is not detected (see section on "what is a colonoscopy").

  • Damage to other organs

    Very rarely, damage can occur to the other organs during colonoscopy such as damage to the spleen. This is a very, very rare complication.