Anal Fissures

Question 1

Define Anal fissures

Answer 1

An anal fissure is a longitudinal tear of the perianal skin distal to the dentate line characterised by pain on defecation and rectal bleeding.

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

Question 2

Explain the aetiology / risk factors of anal fissure

Answer 2

• Passage of a hard stool bolus (opiate analgesia can cause constipation)
• Secondary to Crohn’s Disease
• Pregnancy
• Anal sex

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 3

Recognise the presenting symptoms of anal fissure

Answer 3

• Pain on defecation (like passing glass)
  
  • Lasts for a while after passing stool
  • Tearing sensation
• Fresh blood on toilet paper

Question 4

Signs on physical examination

Answer 4

• Increased anal sphincter tone (anal spasm)
  
  • The exposed internal sphincter muscle beneath the tear goes into spasm. This causes severe pain. The spasm also pulls the edges of the fissure apart, making it difficult for your wound to heal.
• Sentinel skin tag

Question 5

Identify appropriate investigations for anal fissure and interpret the results

Answer 5

• Clinical diagnosis
• DRE is CONTRAINDICATED

Question 6

Generate a management plan for anal fissure

Answer 6

Conservative management is preferred (acute fissures)

• Dietary improvement (e.g., adequate ingestion of dietary fiber and water)
• Stool softeners (e.g., docusate)
• Topical analgesia (e.g. lignocaine)

Chronic fissures:

• Sitz baths
• Topical vasodilator therapy: CCB gel (e.g., nifedipine)/GTN cream

Most patients heal withing 6-8 weeks. If not:

• Botulinum toxin injection
• Surgical sphincterectomy

Question 7

Identify the possible complications of anal fissure and its management

Answer 7

• Chronic anal fissure
• Incontinence after surgery
• Recurrence of fissure