Colonoscopy and Flexible Sigmoidoscopy

Male colon anatomy - digestive systemColonoscopy and Sigmoidoscopy are both generally day case procedures that can be done with or without sedation and pain relief.

A sigmoidoscopy is a limited evaluation of the lower GI tract evaluating the last 40-50cm of colon. It is generally done to evaluate symptoms of fresh (red) rectal bleeding or left sided abdominal pain or in the evaluation of known disorders such as colitis. The procedure lasts around 10 minutes and is done unsedated. Samples and photos may well be taken during the procedure. Prior to the procedure, you will be given an enema to clear the last part of your bowel so that clear views of the lining of your bowel can be obtained. You will be able to leave without an escort after the procedure as no sedation is used.

Prior to colonoscopy, the bowel needs to be cleared using a bowel preparation that will result in you passing a clear or yellow liquid having taken upto 2 litres of water and laxative. The prep for the procedure will be discussed with you before the colonscopy in clinic and by the Endoscopy Nursing team. Some people find the prep worse than the procedure itself.

There are certain medications that will need to be stopped prior to the Colonoscopy and this will be discussed prior to the procedure. I need to know if you are taking any blood thinning agents such as warfarin or clopidogrel (plavix) as they may well need to be stopped in advance of the procedure. In addition, if you are taking an iron preparation, this will need to be stopped 7-10 days prior to the colonoscopy.

As you will have likely been seen in clinic beforehand, sedation will have been discussed with you already. The sedation that is used for colonoscopy is midazolam that is given to you through a canula (plastic tube inserted into a vein in your arm prior to the procedure). This is a short acting sedative that will generally make you drowsy and also forget what is happening during the procedure. In the doses that are used for endoscopy, it is generally safe with very few side effects. The pain relief that is used is pethidine given through the canula. If you are allergic to this, there are alternatives that can be used, but please tell me in advance.

There are certain medical conditions such as chest conditions that may preclude the use of sedation and pain relief, but if there are no medical reasons not to use it, you can choose to have sedation and pain relief as long as you bring someone to take you home and look after you for at least 12 hours after the procedure. You should not drive for 24 hours after sedation or operate machinery and certainly not sign any important documents.

If you wish not to have sedation and pain relief, Entonox can be used which is breathed in during the procedure and provides a good level of pain relief and driving is allowed an hour after the procedure. However, there are certain conditions that can potentially make colonoscopy more uncomfortable such as Irritable Bowel Syndrome or a previous hysterectomy and diverticular disease. I would recommend consideration of sedation of pain relief under these circumstances.

During the procedure as the endoscope is passed around the bowel, it is likely you will be turned on the trolley or one of the nurses will apply pressure to your abdomen to aid the passage of the scope. Photos and samples may well be taken and if I find a polyp (which is a benign small growth in the bowel that if left could be come cancerous) I will remove this if it is technically possible to do so.

Both sigmoidoscopy and colonoscopy are very safe, but there are some risks to be aware of. Perforation (causing a tear) is possible and sigmoidoscopy carries a risk of 1:5000 and colonoscopy 1:1500. If a tear were to occur, surgery may be required including the requirement of a stoma (bag) temporarily. Removing a polyp carries a greater risk of causing a tear, but due to their potential to become a bowel cancer, it is generally a good idea to remove them. Bleeding is another complication that can occur immediately after the procedure or can be delayed up to 10-14 days in certain circumstances if certain types of polyp are removed.

Very often the results of the procedure will be given to you on the day before you go home.

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