Anal Fissure Flashcards
What is an anal fissure?
An anal fissure is a tear in the mucosal lining of the anal canal, most commonly due to trauma from defecation of hard stool.
How can anal fissures be classified?
It can be classified according to its duration:
- Acute: present for <6 weeks
- Chronic: present for >6 weeks
What are the risk factors for anal fissures?
Anal fissures are usually caused by inflammation or trauma to the anal canal. The major risk factors include:
- Constipation
- Dehydration
- Inflammatory bowel disease
- Chronic diarrhoea
What are the clinical features of anal fissures?
The most common presenting feature of an anal fissure is intense pain post-defecation, which can last several hours. Pain can be far out of proportion to the size of the fissure. Other associated symptoms may include bleeding (commonly bright red blood on wiping) or itching, both typically post-defecation.
On examination, fissures can be visible and / or palpable (albeit very painfully) on digital rectal examination. Most fissures present in the posterior midline (90% cases); anterior fissures are more likely to in females or if an underlying cause is present.
What investigations should be ordered for an anal fissure?
Often patients will refuse a digital rectal examination due to the intense pain and examination under anaesthesia (EUA) may be necessary for diagnosis. Fissures within the anal canal can then usually be identified upon proctoscopy.
Briefly describe the medical management of an anal fissure
The medical management of an anal fissure involves reducing risk factors and providing adequate analgesia. The majority of patients do not require surgery.
Measures such as increasing fibre and fluid intake will help. Stool softening laxatives (such as Movicol or Lactulose) can be trialled if there is no change in stool following initial conservative management. Topical anaesthetics, such as lidocaine, or hot baths can help to relax the anal sphincter and also help the healing process.
If patients are still symptomatic, the next line of management is GTN cream or diltiazem cream. This increases the blood supply to the region and relaxes the internal anal sphincter, putting less pressure on the fissure, promoting healing and reducing pain.
Briefly describe the surgical management of an anal fissure
Surgical therapy is reserved for chronic fissures where medical management has failed to resolve the symptoms. Botox injections can be given into the internal anal sphincter, to relax and promote healing. A lateral sphincterotomy can be performed, involving division of the internal anal sphincter muscle.
What are the complications of anal fissures?
Recurrence of anal fissures post-surgery is between 1-5%, but studies have shown that the majority of these recurrence patients are those with an underlying predisposition to the condition. The main complication is faecal incontinence.
What differentials should be considered for an anal fissure?
The differential diagnoses include haemorrhoids, Crohn’s disease, ulcerative colitis or anal cancer.
