Anal fissures

Question 1

What is it?

Answer 1

Anal fissures are longitudinal or elliptical tears of the squamous lining of the distal anal canal.

Question 2

What defines an acute anal tear and chronic anal tear?

Answer 2

If present for less than 6 weeks they are defined as acute, and chronic if present for more than 6 weeks.

Question 3

What are the risk factors to anal fissures?

Answer 3

constipation
inflammatory bowel disease
sexually transmitted infections e.g. HIV, syphilis, herpes

Question 4

What are the features of anal fissures?

Answer 4

painful, bright red, rectal bleeding

around 90% of anal fissures occur on the posterior midline.

if the fissures are found in alternative locations then other underlying causes should be considered e.g. Crohn’s disease

Question 5

Management of acute anal fissure?

Answer 5

soften stool
dietary advice: high-fibre diet with high fluid intake
bulk-forming laxatives are first-line - if not tolerated then lactulose should be tried

lubricants such as petroleum jelly may be tried before defecation

topical anaesthetics

analgesia

Question 6

Management of chronic anal fissures?

Answer 6

same as acute and:

topical glyceryl trinitrate (GTN) is first-line treatment for a chronic anal fissure

if topical GTN is not effective after 8 weeks then secondary care referral should be considered for surgery (sphincterotomy) or botulinum toxin