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Anal fissures

Anal fissures


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Anal fissure
Gastrointestinal system
An anal fissure is a small tear in the skin surrounding the anus. It can be extremely painful and will often bleed, especially when going to the toilet and passing faeces. Anal fissures should not be confused with haemorrhoids or piles that are usually painless when going to the toilet and tend to itch.

Anal fissures are very common, although it is difficult to get a precise figure, it is estimated that they occur in about 15 out of every 10,000 people. Children and adults of both sexes can get anal fissures, but they are particularly likely to occur in males between the ages of 30 and 40, and in women between the ages of 20 and 30.

An anal fissure tear usually extends backwards from the anus between the cheeks of the buttocks. In about 10% of women with an anal fissure, the tear extends forwards, the strain of labour often being the cause.

Anal fissures are not normally serious. In the majority of cases, the fissure will heal naturally within 6 weeks, others may take longer to heal. Anal fissures that last less than 6 weeks are called acute anal fissures, those that last longer than 6 weeks are called persistent or chronic anal fissures.

In some cases, there are multiple tears around the anus but this may be a symptom of a more serious condition such as inflammatory bowel disease or anal herpes.
The most common cause of an anal fissure is constipation. Straining to pass large or hard faeces over-stretches the skin surrounding the anus causing it to tear. In children, the severe pain associated with anal fissures can make them reluctant to go to the toilet. As a result, they become more constipated, creating a vicious circle that increases pain.

During childbirth, the strain of bearing down to deliver the baby may cause the skin between the vagina and anus to split producing a forward running tear.

Other causes of anal fissure include damage through severe diarrhoea, anal intercourse or rectal examinations.

Once an anal fissure has formed, the ability of the fissure to heal appears to depend on the pressure within the anal canal. This idea is supported by the finding that patients with chronic anal fissures have a much higher anal canal pressure than those without anal fissures. There are two bands of muscle, called the internal anal sphincter and the external anal sphincter that control the opening of the anus during a bowel movement. The pain caused by an anal fissure is thought to cause the internal anal sphincter to contract or go into spasm. When this happens, the pressure in the internal anal sphincter increases which, in turn, constricts the blood supply to the anal skin. A reduced blood supply reduces the ability of the anal skin to heal, so the fissure becomes chronic.
The pain of an anal fissure can be excruciating and has been described as a knife-like pain, or like passing broken glass. The intense pain starts during the bowel movement and may continue to be intensely painful for up to 2 hours, with the area remaining painful for days. The pain is usually accompanied by bleeding and sufferers may notice some bright red blood on the toilet paper. Sometimes, small tags of skin will appear on the edge of the anus.

Most people think that pain in the anal area is caused by piles or haemorrhoids, but this is not always the case. If pain is particularly severe, occurs when going to the toilet and lasts for several days, then an anal fissure is likely to be the cause.
Treatment depends upon whether the anal fissure is acute or chronic.

For an acute anal fissure, faecal softener laxatives such as docusate sodium will help pass bowel movements more easily. However, as no laxative should be taken regularly, once constipation is relieved, a change to a high fibre diet and regular exercise will help keep bowel movements regular.

For pain relief, simple pain killers such as paracetamol are usually sufficient to control pain while the fissure heals. Pain killers containing codeine, including co-codamol and co-codaprin, should be avoided as these may cause constipation and make the fissure worse.

Topical preparations in the form of ointments or creams containing local anaesthetic agents such as lidocaine, or corticosteroids such as hydrocortisone may be applied directly to the anal area to reduce pain and inflammation. These preparations should only be used for short periods as over-use may sensitise the skin, making it red and sore, or may thin the skin making it more likely to tear.

With chronic anal fissures, an ointment containing glyceryl trinitrate will usually be prescribed. When applied into the anal canal it relaxes the internal anal sphincter and reduces anal pressure. As this occurs, blood supply is restored to the anal skin, allowing healing to proceed. Relaxation of the anal sphincter also reduces spasm, thereby reducing the intensity of the pain.

Similarly, a cream containing diltiazem may be applied around the outside of the anus. The diltiazem helps the muscles around the anus to relax and stretch, helping reduce pain and tearing during a bowel movement.

About half of patients using glyceryl trinitrate ointment or diltiazem cream will experience headaches. These headaches can normally be relieved with paracetamol and will generally ease with time.

Injections of botulinum toxin into the muscle of the anus may also be used. Botulinum toxin blocks transmission of nerve impulses to the muscle and prevents spasm of the muscle, reducing pain of bowel movements and helping the fissure to heal.

Two out of three people treated for a chronic anal fissure will respond to non-surgical treatments. If there is no improvement, then surgery may be necessary. Procedures called an internal sphincterectomy or anal dilatation (cutting or stretching the internal anal sphincter), performed under a general anaesthetic, are usually effective in about 95 out of every 100 cases. However, these procedures do carry a small risk of the person later being unable to control the escape of faeces or wind.
When to consult your pharmacist
Talk to your pharmacist if you think that you may have an anal fissure. Your pharmacist will ask you to describe your symptoms to decide whether you are likely to be suffering from haemorrhoids, an anal fissure or some other complaint.

If the pharmacist suspects that you have an anal fissure and it has occurred recently, then you may be offered laxatives, simple analgesics or topical treatments to ease the condition while the fissure heals. If your symptoms sound as if you have a chronic anal fissure your pharmacist will advise you to see your doctor.
When to consult your doctor
If your pain is particularly severe during and after your bowel movements and lasts for over a week then you should see your doctor. You should also see your doctor if you have been using over the counter remedies for over 2 weeks and they have not worked. Your doctor will question you about your bowel movements, your diet and will examine your anal area to confirm whether you have an acute or chronic anal fissure or some other condition and will treat accordingly. If prescribed treatments fail to work, your doctor may decide to refer you to a hospital for surgery.
Living with an anal fissure
As constipation is the main cause of anal fissures, maintaining regular bowel movements will help reduce the risk of an anal fissure developing or recurring. Eat a well balanced diet rich in dietary fibre such as wholemeal bread, bran, fresh fruit and vegetables and drink plenty of water throughout the day. Cut down on the amount of alcohol, tea and coffee as these can cause dehydration and lead to constipation.

If you do become constipated, use a faecal softener laxative such as docusate sodium rather than a stimulant laxative such as senna. Docusate sodium absorbs water into the faeces making it easier to pass, whereas a stimulant laxative forces hard faeces that may result in tearing. Once constipation is relieved, change to a high fibre diet and take regular exercise as a means of keeping bowel movements regular. Do not take laxatives regularly as the gut becomes less sensitive and eventually fails to function normally without them.

To ease pain, try soaking in a hot bath. Washing your bottom in warm water after each bowel movement is also soothing.
Useful Tips
  • Keep stools soft by eating a high fibre diet (brown bread,cereals and fresh fruit and¬† vegetables)
  • ¬†Drink plenty of water; aim for 6-8 glasses a day
  • Avoid excess tea and coffee
  • Always go to the toilet when you feel the urge
  • Wash around the anal area after each bowel movement
  • Wash your hands thoroughly after applying any preparations to the anal area

Reviewed on 14 December 2010