Anal Fissure

Question 1

Define

Answer 1

• A painful tear in the squamous lining of the lower anal canal

NOTE: 90% of anal fissures are posterior (anterior anal fissures tend to occur after childbirth)

• Acute: present for less than six weeks.
• Chronic: present for six weeks or more.

Question 2

Causes

Answer 2

Primary: no apparent cause

Secondary causes:
→ Constipation (hard stool), IBD (ulceration with inflammatory process), STD, rectal malignancy

Aetiology of primary anal fissures is unclear
Associated with ↑anal tone and ischemia hindering healing process

Most are caused by hard faeces

Anal sphincter spasm can constrict the inferior rectal artery, causing ischaemia and impairing the healing process

Rare causes: syphilis, herpes, trauma, Crohn’s, anal cancer, psoriasis

Question 3

Epidemiology

Answer 3

Affects 1/10 people during their life time

Both sexes are affected equally

Can occur at any age

Most cases occur in children and young adults: 10-30 yrs

Question 4

Symptoms

Answer 4

• Pain on defecation (passing shards of glass) 
• Pain may persist for several hours after
•  ±Bright, fresh blood on passing stools

Also:
Bowel habit – constipation, diarrhoea, recent change
Associated symptoms – abdomen pain, ↓weight, rectal discharge FHx – relating to IDB and colorectal disease

Question 5

Signs

Answer 5

Abdominal exam: faecal loading

External examination of the anus: linear split of mucosa Majority are posterior and in the midline
Do not attempt DRE (too painful if acute)

Question 6

Investigations

Answer 6

Abdominal exam: faecal loading

External examination of the anus: linear split of mucosa Majority are posterior and in the midline
Do not attempt DRE (too painful if acute)

Question 7

Management

Answer 7

Keep stools regular and soft

• Adequate fluid intake
• Consider laxatives
• ↑fibre 18-30g/day (wholegrain, veg, fruit)

Treat underlying conditions

• Pain relief
• Oral analgesia (paracetamol, ibuprofen prn)
• Warm baths
• Consider GTN ointment (relax SM, ↓anal tone)
• Consider topical anaesthetic if pain extreme (max 14 day use)

Note: 30% get headache as a GTN side effect

Secondary care

Medical:

• Topical diltiazem (Ca2+ channel block) → vasodilation and SM relaxation, ↓side effects
• Botulinum toxin → more expensive, side effect of potential temporary incontinence flatus/faeces

Surgical: internal sphincterectomy
Continence issues may follow (30% flatus, 20% soiling)

Question 8

Complications

Answer 8

Tear fails to heal - becomes chronic, extensive scarring
Anal fistulas
Anal stenosis (abnormal narrowing due to spasm or contraction of scar tissue)

Question 9

Prognosis

Answer 9

Most heal in 2 weeks with conservative management Although reoccurrence is common (50% in those treated with GTN)

For secondary AF, dependant on underlying pathology