An anal fistula is a newly formed duct in the tissue of the anal area. Such a duct begins in the anal canal and leads away from there. Sometimes it ends at the skin so that purulent discharge or feces come out. Other symptoms include itching, pain or inflammation. The cause of an anal fistula is often an anal abscess. An anal fistula rarely disappears on its own. You should therefore consult a doctor quickly.
Here you will find further information and selected doctors for anal fistulas.
A fistula generally refers to a connecting duct in the tissue that is not part of normal development. Fistulas can form in various areas of the body. Sometimes they are already present at birth (e.g. anal atresia), but they usually only develop in the course of life as a result of other diseases.
Anal fistulas develop at the proctodeal glands(scent glands) in the anal canal and lead to the outside of the skin. They permanently release secretions and, if they are large enough, also faeces, which is why they can often cause extremely unpleasant discomfort.
The risk of developing an anal fistula is 1 to 3 percent, which means that 1-3 out of 100 people will develop an anal fistula during their lifetime. Men are more frequently affected than women. It is a relatively common disease in young men between the ages of 30 and 50.
The cause of an anal fistula is often an anal abscess. Anal fistulas and anal abscesses have some things in common. An anal abscess is caused by bacteria. Here, purulent secretions accumulate in a capsule in the anal canal. If this inflammation becomes chronic, ducts can form and an anal fistula develops.
Other causes of an anal fistula can be
Anal fissures are small tears in the anal area. If this causes inflammation, it can develop into a fistula.
Hemorrhoids are protrusions of the mucous membrane in the area of the mucous membrane of the anus. Fistulas can also develop here, especially in the case of infections.
Chronic inflammatory bowel diseases such as ulcerative colitis or Crohn's disease can also lead to the formation of fistulas. This occurs more frequently in Crohn's disease, but here the fistulas form in the entire gastrointestinal tract from the mouth to the anus. In ulcerative colitis, the risk of fistula formation is lower, but limited to the rectum.
Malignant diseases of the rectum(rectal carcinoma and anal carcinoma) can also lead to the formation of anal fistulas, but here too usually as a result of an accompanying infection.
Whether a fistula is visible from the outside depends on its distance from the skin of the anus, its course through the sphincter muscles and its depth.
There are five different types of anal fistula, depending on their shape and course.
The classification is based on
There is an external (M. sphincter ani externus) and an internal (M. sphincter ani internus) sphincter muscle, both of which lie next to each other and are responsible for controlling bowel movements (continence). The external sphincter in particular is of great importance here, as it is controlled voluntarily.
The classification of anal fistulas according to the distance to the anus is as follows (the distance increases from top to bottom):
The first three types are common, while the last two types of anal fistula are rather rare.
Illustration of different anal fistula forms and their progression © bilderzwerg | AdobeStock
Those affected either don't notice the fistula at first or it appears as a kind of pimple in the anal area. This supposed pimple can swell, itch or cause pain. It can also lead to purulent discharge.
Abscesses can also cause these symptoms. However, general feelings of illness such as fever or general malaise may also occur. By the time the fistula has formed, these symptoms have usually improved. This is because pus can drain through the fistula and the pressure is significantly reduced.
The following symptoms can occur with an anal fistula:
If a patient is suspected of having an anal fistula, a visit to a specialist for rectal diseases, a proctologist, is indicated.
During the examination, the anal area is first palpated. In addition, a rigid metal tube with a light source at the end (medical proctoscope) is often inserted. This allows the walls of the anal canal to be assessed so that, in addition to anal fistulas, abscesses can also be detected.
can be identified.
As an anal fistula can also be caused by a malignant tumor, tissue samples should always be taken from suspicious findings and then examined histologically.
A fistula probe is used to determine the course of a fistula. This is a metal tube that is carefully inserted into the fistula tract from the outside and can ideally be visualized on the inside with a proctoscope.
Most uncomplicated fistulas can be diagnosed using this method. In the case of complex or multiple (several) fistulas and suspected abscesses, additional ultrasound examinations and an MRI are also helpful tools for detecting any damage in the anal area.
In many cases, an anal fistula needs to be treated surgically, as it rarely heals on its own.
Surgical treatment involves splitting the fistula. However, depending on the course of the fistula, there is also a risk of injury to the sphincter muscle. This can be incised or severed during removal. As the external sphincter muscle in particular is important for conscious bowel movement control, it should be cut as little as possible. The risk or necessity of partial or complete damage to the external sphincter is greatest with supra- and extrasphincteric fistulas. Fortunately, these make up only a small proportion of fistulas.
Nevertheless, in extreme cases, the function of the muscle may be impaired. The result is possible incontinence. To avoid this, the sphincter muscle can be sutured back together once the split fistula has healed.
Alternatively, the fistula can also be closed plastically and sutured shut. With this method, however, there is a higher risk of a recurrence of an anal fistula.
Patients suffering from chronic intestinal diseases cannot always be operated on. They are also at risk of developing anal fistulas more frequently or again. They then either have to live with these fistulas or find relief by taking other medication. Fistula drainage may also be indicated here.
If anal fistulas are completely removed, the prognosis is good to very good. However, the healing process can often take several weeks and can sometimes be very painful. It is particularly important that patients ensure adequate anal hygiene - especially after surgery. However, the preventive effect of good anal hygiene should also be emphasized at this point, especially as this can prevent anal fistulas or inhibit their growth.
However, if the fistulas cannot be completely removed, problems can continue to occur. People who suffer from Crohn's disease or other bowel diseases have a particularly high risk of developing anal fistulas.
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