An anal fissure is a benign tear caused by acute constipation.
Associated with severe pain (100%) and minor rectal bleeding (80%).
90% occur midline posteriorly and 10% midline anteriorly.
Be suspicious of any ‘fissure’ that is painless or not in the midline.
A small inter-sphincteric abscess may present with similar symptoms.
Acute fissures are associated with sphincter spasm and it is often not possible to perform a full rectal examination due to pain.
Gentle pressure on either side of the anal opening with the thumbs will often allow enough relaxation of the sphincter for the edge of the fissure to be seen, allowing confirmation of the diagnosis.
Treat fissures medically initially.
Medical treatment is aimed at reducing the sphincter spasm and will allow healing in 60-80% of cases:
- Constipation – dietary advice, simple laxatives and stool softeners.
- 1st line – GTN ointment 0.4% (Rectogesic) twice daily for six weeks even if symptoms resolve (warn about headaches). .
- 2nd line – 2% Diltiazem ointment (Anoheal) twice daily for six weeks. Response rates are similar to GTN first line treatment (warn about anal discomfort side-effect).
Patients who fail to respond to conservative treatment should be referred to the Colo-Rectal department.
Surgical options include injection of Botox to the sphincter, excising the fissure if it has become chronic (often combined with Botox) and lateral internal sphincterotomy.
Links to NICE Guidance