Anal fissure

Question 1

What are they?

Answer 1

Anal fissures are longitudinal or elliptical tears of the squamous lining of the distal anal canal. If present for less than 6 weeks they are defined as acute, and chronic if present for more than 6 weeks.

Question 2

Risk factors

Answer 2

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

Question 3

Features

Answer 3

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 4

Management of an acute anal fissure (< 1 week)

Answer 4

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 5

Management of a chronic anal fissure

Answer 5

the above techniques should be continued
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