Contents
Tear in the anoderm distal to the dentate line.
Aetiology
- Low-fibre diet
- Constipation
Pathophysiology
Acute injury
↓
Local pain & spasm of the internal anal sphincter → ↑ resting anal sphincter pressure
↓
↓ blood flow
↓
Ischaemia and poor healing
Unless this cycle is broken the fissure will persist.
Site:
- Posteriorly midline fissure (M/C, 90% cases; d/t poor perfusion)
- Anterior fissure (10% cases; usually younger, mostly female, patients often with injury to or dysfunction of the external anal sphincter)
- Lateral/multiple fissures (<1% cases)
Clinical features
- Anal pain, spasm, and/or bleeding with defecation
Complications:
- Bleeding
- Pain
- Infection
- Incontinence
- Fistula formation (M/serious)
Diagnosis
Differential diagnosis:
Other causes of severe anal pain
- Thrombosed external haemorrhoids
- Anal fissure
- Acute herpetic ulceration or other STD
- Crohn’s ulceration & inflammation
- Anal, rectal or pelvic cancer
- Lymphoma/leukaemia
Management
Surgical management:
