Colonoscopy and flexible sigmoidoscopy

Summary

Definitions

The colonic mucosa is examined with and therapy delivered through, a flexible endoscope (also see Chapter on OGD). A limited examination of the sigmoid and descending colon, usually to the splenic flexure (approximately 60 cm with a straight scope), is termed ‘flexible sigmoidoscopy’. With full ‘bowel prep’ and sufficient dexterity ‘colonoscopy’ can be performed when a scope is passed to the caecum, allowing access to the entire colonic mucosa, and the terminal ileum if necessary.

Indications

COLONOSCOPY

1. ▪ Iron deficiency anaemia

2. ▪ Blood in the stool or rectal bleeding

3. ▪ Altered bowel habit (diarrhoea or constipation)

4. ▪ Significant, unexplained weight loss, accompanied by gastrointestinal symptoms

5. ▪ A family history of colon cancer

6. ▪ A history of previous colon polyps or colon cancer

7. ▪ Cancer screening in people with ulcerative colitis

8. ▪ To assess inflammatory bowel disease

9. ▪ Chronic, unexplained abdominal pain.

FLEXIBLE SIGMOIDOSCOPY

This is a limited examination and should not be performed when there is a significant chance of missing serious proximal pathology (50% of all colon cancers are proximal to the splenic flexure), hence indications are limited. Senior advice/local guidelines should be sought if you are not sure which examination to book. The common indications are:

1. ▪ Minimal bright red rectal bleeding

2. ▪ As a screening test in asymptomatic people to detect colon polyps or colon cancer

3. ▪ Persistent diarrhoea with no alarm symptoms e.g. in diagnostic workup for irritable bowel syndrome

4. ▪ After radiation treatment to the pelvis when a patient has lower gastrointestinal symptoms

5. ▪ To assess inflammatory bowel disease.