Anal Fissure

Question 1

Define anal fissures

Answer 1

Split in the skin of the distal anal canal (large bowel between rectum and anus) characterised by pain on defecation and rectal bleeding

Acute: split <1-2 weeks
Chronic: split persists >6 weeks, often shows infuriated edges, skin rage and visible internal anal sphincter fibres

Question 2

Aetiology of anal fissures

Answer 2

Passage of hard stool bolus (constipation, opioid use, dehydration, pregnancy)
May occur spontaneously

Question 3

Epidemiology of anal fissures

Answer 3

Often affects young adults 15-40

May occur in children

Question 4

Symptoms of anal fissures

Answer 4

Pain on defection (sharp, “passing sharp glass”, 10/10, tearing followed by burning for hours)
Fresh blood seen on stool or paper 
Anal spasm 
Skin tag (sentinel pile) 
Fissure visibly on buttock retraction

Question 5

Signs of anal fissure

Answer 5

Fresh blood
Sentinel blood
Visible fissure

Unable to DRE due to pain

Question 6

Investigations for anal fissures

Answer 6

Clinical diagnosis

DRE will be too painful

Resistant:
Anal manometry: low resting pressure
Anal USS: defect in the internal or external anal sphincter

Question 7

Management for anal fissures

Answer 7

Most are shallow and will heal spontaneously within a few weeks. Deep fissures have poorer healing as the sphincter spasm impairs anal blood supply

On presentation:
Conservative: High fibre diet | adequate fluid intake | sits baths | topical analgesia | stool softeners

Adjuncts: Topical GTN (SE: headache) | topical diltiazem (CCB) if GTN intolerable

Question 8

Management for resistant anal fissures

Answer 8

Botulinum toxin injection (relax anal sphincter)

Surgical sphincterotomy (remove internal anal sphincter to reduce spasm)

Anal advancement flap

Question 9

Complications of anal fissures

Answer 9

Chronic fissure
Recurrence
Incontinence after surgery

Question 10

Prognosis of anal fissures

Answer 10

60% heal in 6-8 weeks
20% heal after diltiazem
20% require surgery