Anal Abscess-Fistula

What is an anal abscess

An anal abscess is an infected cavity filled with pus found near the anus or rectum (back passage).

What is a Fistula

An anal fistula is a track between the skin on the outside and the anal canal (back passage) on the inside. There are many different types of fistulae, from relatively simple to a complex branching network of tracks. Some involve the muscles responsible for bowel control. Each one is individual but is almost always the result of a previous abscess.

What causes an abscess?

An abscess results from an acute infection of a small gland just inside the anus, when bacteria or foreign matter enters the tissue through the gland. Certain conditions – colitis or other inflammation of the intestine, for example – can sometimes make these infections more likely.

What causes a fistula?

After an abscess has been drained, a tunnel may persist, connecting the anal gland from which the abscess arose to the skin. If this occurs, persistent drainage from the outside opening may indicate the persistence of this tunnel. If the outside opening closes, recurrent abscesses may develop.

What are the symptoms of an abscess of fistula?

Symptoms of both ailments include constant pain, sometimes accompanied by swelling that is not necessarily related to bowel movements. Other symptoms include irritation of the skin around the anus, discharge of pus (which often relieves the pain), fever, and feeling poorly in general.

Does an abscess always become a fistula?

No. A fistula develops in about 50 percent of all abscess cases, and there is really no way to predict if this will occur.

How is an abscess treated?

An abscess is treated by draining the pus from the infected cavity, making an opening in the skin near the anus to relieve the pressure. This is usually done in hospital under a general anaesthetic.

What about treatment for a fistula

Surgery is necessary to cure an anal fistula. Fistula surgery usually involves cutting a small portion of the anal sphincter muscle to open the tunnel, joining the external and internal openings. and converting the tunnel into a groove that will then heal from within outward.

Many different operations can be done for a fistula. You should discuss with your surgeon exactly what is planned for you. The aim is to cut out or lay open the infected tract so as to promote healing from the base of the wound out to the surface, preventing unhealed pockets of infection from being left trapped inside. This healing can be a slow process, taking from a week or so up to several months. It is impossible to predict how long it will take in each individual case. Further inpatient treatment, with a visit to the operating theatre, may be required. Sometimes a stitch (called a seton) is inserted to avoid dividing the muscle. Your surgeon will explain this to you if it is needed in your case.

After the Operation

  • When you are awake and the effects of the anaesthetic have worn off, you will be able to eat and drink and get up as you wish.
  • You may have a dressing in place around the entrance to the anus, to control any bleeding in the area. This can feel strange and possibly rather uncomfortable and it may make you feel that you want to open your bowels (although you are not likely to do so).
  • Some discomfort is to be expected. Painkillers are available, so please ask your nurse if you need something to help with discomfort.
  • You will normally have a bath the next day and this will soak the dressing out (it may need a little gentle pull). It is quite possible that there will be some blood loss in the bath (do not be alarmed – this can make the water look very red!).

When Will I open my bowels?

From the day after your operation you may be given laxatives. This will soften the stools and stimulate a bowel action. You may not open your bowels for a day or two, and when you do some discomfort and a little bleeding may be present. This is to be expected.

Dressing your wound

This will depend on the operation which has been performed but generally once a day, after a warm bath/shower, your wound may require dressing. Experience has shown that it is very important that the fistula tract heals from the base upwards towards the surface. To promote healing from the base of the wound without pocket formation, the nurse dressing your wound may gently insert a finger along the tract at the time of the dressing. This may be uncomfortable but is essential if your fistula is to be given the best chance of healing and not recurring.

How long will I be in hospital?

This varies between individuals, and depends on the type and complexity of the fistula. For a simple fistula it will be around 1-2 days; for a more complex one it is likely to be 3-5 days.

What should I do if I bleed after I go home?

It is likely that there will be a small amount of bleeding from the wound or the anus after the operation. You may notice this after your dressing has been done, or on your stool or on the toilet paper when you wipe yourself. This is normal and nothing to worry about. You may also have a discharge from the wound for some weeks. It is a good idea to wear a small pad inside your pants to protect your clothes from any staining.

How long should I stay off work?

The time taken to get back to normal activities varies for different people and with the extent of your surgery. Do as much as you feel comfortable doing. If you need to take painkillers these may make you drowsy so you should avoid driving or operating machinery. If lifting causes you discomfort you should avoid it. Most people need a week or two off work once they go home but this will depend on what you do and the extent of your fistula. It is unlikely that you will do any harm by returning to work early.

It is advisable to avoid sitting still or walking for long periods at first. You should not go swimming until your wound has healed as the chlorine in the water may affect wound healing and there is a chance of picking up or passing on an infection. You may find that vigorous exercise is uncomfortable. Start with gentle walking and build up your activity level gradually. You can resume sexual relations as soon as you feel comfortable to do so.

Are there any long-term effects of the operation?

In a very few cases if someone has weak muscles around the back passage (anal sphincter) and a tendency to difficulty in controlling the bowels or leakage, this may worsen after the operation. If this becomes problematic you should consult your specialist to see if anything can be done to improve your bowel control.