Table Of Contents
Anal fissure
An anal fissure is a superficial tearing of the skin over the anal sphincter (anoderm). It is related to prolonged bouts of straining or child-birth (post-partum). Diagnosis is clinical, as fissures can be seen on examination by carefully spreading the buttocks. 90% of fissures occur at the anterior and posterior midline. Posterior fissures are related to the passage of hard stool, while anterior fissures suggest underlying organic disease and warrant endoscopy. Fissures in other locations should also raise suspicions for Crohn’s disease, tuberculosis, HIV or leukaemia.
Predominantly occurs in younger women (who tend to have tighter external anal sphincter tone).
Anal fissure
| Classification | Description |
|---|---|
| Acute anal fissure | Appears as a tear in the anal skin and often bleeds |
| Chronic anal fissure | Appears as a linear ulceration with heaped-up margins and a sentinel pile (small skin tag) |
- Risk factors
- Constipation
- Hard stools
- Tight anal sphincter
- Signs and symptoms
- Local pain at the fissure site
- Constipation (as a cause and as an effect of the fissure)
- Minor bleeding
- Investigations
- Proctosigmoidoscopy or anoscopy under anaesthesia: to rule out differentials
- Conservative treatment
- Stool softeners
- High-fibre diet
- Lubrication before defectation
- Increased water intake to prevent constipation
- Bulk forming laxatives (first-line). Lactulose is second-line for acute anal fissure (< 6 weeks)
- Topical nitroglycerin or calcium channel bloxers (relaxes the external anal sphincter) for chronic anal fissure (> 6 weeks)
- BoTox injection (for chronic anal fissure > 6 weeks)
- Surgical treatment
- Laser internal sphincterotomy (open or closed): divides the internal anal sphincter reducing sphincter tone. If conservative treatment fails
- Prognosis
- CCBs and topical nitroglycerine relieve pain and cause healing in 50% of fissures
- BoTox relieves pain and causes healing in 60-80% of fissures
- 95% of chronic fissures heal after surgery. Recurrence is uncommon.
- Complications
- Incontinence, usually to flatus (5-15% of patients have some degree of incontinence)
