Colonoscopy and Sigmoidoscopy

Colonoscopy and sigmoidoscopy are used to investigate the colon and rectum (large bowel) and to remove polyps.

Patients with bowel symptoms such as bleeding, change in bowel habit or abdominal pain may be recommended for sigmoidoscopy or colonoscopy.  Sigmoidoscopy is the baby brother to colonoscopy and is a camera test that looks at the lower part of the bowel (anus, rectum and sigmoid colon).  Patients are often given a laxative enema via the anus 1 to 2 hours beforehand and they usually do not require any sedation.  Colonoscopy is a camera test that not only looks at the lower part of the bowel but also the rest of the entire colon.  Patients take strong oral laxatives the day beforehand and are given intravenous sedation and painkillers just before the procedure.  Colonoscopy is very useful for diagnosing bowel or colorectal cancer, diverticular disease, inflammatory bowel disease and polyps.  Polyps are small moles on the inside lining of the colon and rectum and it is thought that sometimes these can change in to bowel cancers.  The specialist can often remove polyps during the colonoscopy and they can be sent away to the laboratory for analysis.  Both sigmoidoscopy and colonoscopy are usually performed as a day case procedure.

Sigmoidoscopy or colonoscopy are usually recommended for patients with symptoms of rectal bleeding, abdominal pain, change in bowel habit and anal irritation.  This is because the symptoms of serious bowel conditions like bowel and anal cancer are very similar to the symptoms of less serious conditions like piles or haemorrhoids.  Therefore doctors usually cannot be confident of telling a patient if they have a serious or less serious bowel condition unless the bowel has been directly visualised with a sigmoidoscope or colonoscope.  Sometimes alternative investigations may be recommended but colonoscopy remains the gold standard for investigating rectal bleeding and change in bowel habit.

Patients with bleeding out of the anus, altered bowels, abdominal pain or anal symptoms should not be embarrassed about making an early appointment to see their doctor and they should make sure that their doctor properly examines their anus and rectum.  This is because the outcome for patients with serious conditions like bowel and anal cancer are considerably improved if any necessary treatment can be started as early as possible.