A 24-year-old man presents with rectal bleeding and a 'sharp, stinging' pain on defecation

A 24-year-old man presents with rectal bleeding and a 'sharp, stinging' pain on defecation. This has been present for the past two weeks. He has a tendency towards constipation and notices that when he wipes himself fresh blood is often on the paper. Rectal examination is limited due to pain but no external abnormalities are seen. What is the most likely diagnosis?
A. Internal haemorrhoids
B. Anal carcinoma
C. Rectal polyp
D. Anogenital herpes
E. Anal fissure

Answer:
E. Anal fissure

Discussion: The combination of pain and bleeding is very characteristic of anal fissures. Pain is a feature of thrombosed external hemorrhoids but is unusual with internal hemorrhoids. Superficial anal fissures may be difficult to see on examination.

Anal fissure 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. Around 90% of anal fissures occur on the posterior midline

Management of an acute anal fissure (< 6 weeks) :
 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
 topical steroids do not provide significant relief.

 Management of a chronic anal fissure (> 6 weeks):
 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 referral should be considered for surgery or botulinum toxin