Anal fistula

Anal fistula is a small channel that forms between the end of the intestine, better known as the anal canal, and the skin near the anus.

Looks like a small sore on the skin of the anus, representing an opening through which unnecessary waste products from digestion leave the body.

Perianal fistulas are usually classified as:

  • Simple or complex – depending on whether the fistula channel is single or with multiple branches and several openings on the skin;
  • Low or high – depending on the location and how far they are from the ring-shaped muscles of the anal sphincter.

Anal fistula – what can cause it and how is it treated

Characteristic symptoms

Several are the most characteristic manifestations that indicate the presence of a fistula:

  • Irrited skin around the anus;
  • Throbbing, constant pain that worsens when sitting, walking, defecating, or coughing;
  • Discharge of pus or blood during bowel movements ;

If the fistula was caused by an abscess, the development of the following additional symptoms is possible:

  • High body temperature around 38 degrees Celsius or more;
  • Fatigue;
  • General malaise.

If the fistula due to intestinal inflammation due to Crohn’s disease, the following complaints are possible:

  • Abdominal pain;
  • Diarrhea;
  • Loss of appetite;
  • Weight loss for no reason.

The most common types of fistulas are:

  • Intrasphincter – the fistula channel passes through the internal sphincter and opens on the surface of the skin next to the anus;
  • Transsphincter – the fistula channel passes through the muscle tissues of the internal and external sphincter and opens on the surface in proximity to the skin of the anus.

Other possible types of fistulas:

  • Their internal opening is in another part of the large intestine;
  • They develop in the shape of a horseshoe, with the ends of the fistula canal opening on both sides of the anus;
  • They expand in a different direction and the fistula canal does not open into the anus.

What are the causes

Perianal fistula is most often caused by an anal abscess, which can be the result of diseases affecting the intestines.

Anal abscess is an accumulation of pus that causes painful sensations. It usually develops around a small gland inside the anus after the space around it becomes infected with bacteria.

The cause of the appearance of abscesses is unknown, it more often develops with weakened immunity, such as HIV positive people, as well as with several chronic diseases at the same time.

Abscesses are treated with antibiotics and in most cases drainage of the inflammatory fluid is required. If the anal abscess ruptures before treatment begins, a fistula may form.

It also forms if the abscess is not completely healed or the inflammatory fluid is not completely drained.

In approximately 30-50% of anal abscess cases, a fistula subsequently forms.

Anal fistula can also form from the penetration of infections into the wall of the rectum and into the tissues that surround them, as a result of proctitis and paraproctitis.

Injuries to the terminal part of the large intestine are also among the provocateurs of anal fistulas.

Infectious diseases, including chlamydia and syphilis, surgical interventions performed on the rectum, colon tumors – also last but not least in the list of factors predisposing to the formation of anal fistulas.


The following measures help to detect the anal fistula and determine its condition:

  • Medical examination and manual examination;
  • Laboratory tests of blood, urine, feces and purulent secretions;
  • Irigoscopy and fistulography – examination of the rectum and the fistula itself with with the help of x-rays and a contrast agent;
  • Ultrasonography – ultrasound detects fistulas and their branches;
  • Colonoscopy – with the help of an endoscope, data can be obtained on possible damage to the rectal mucosa , the location of the channels of the fistula is determined;
  • Sphincterometry – allows to evaluate the functionality of the sphincter;
  • Computer tomography – with its help, data is obtained about the state of the organs of the abdominal cavity, necessary in cases where the doctor suspects the presence of complications.

Treatment of anal fistula

Conservative treatment – with its help, the spread of the infection can be stopped and to relieve painful sensations, but does not solve the problem. Antibacterial therapy and painkillers are prescribed, physical therapy may also be recommended.

Usually surgical treatment is required, as in very few cases it is possible for the anal fistula to heal on its own.

The type of intervention is determined by the position of the fistula and whether it qualifies as simple or complex.

The goal of the operation is to heal the fistula, avoiding damage to the sphincter muscles, which can lead to fecal incontinence, where control of defecation becomes almost impossible.

In 85-90% of cases, fistulotomy is applied, which consists of opening through an incision along the entire length of the fistula channel from its internal to its external opening.

The surgeon cleans out its contents. Usually, about 1-2 months after the intervention, the fistula heals and only a flat scar remains.

Anal fistulas are treated according to clinical pathway #181, where the minimum hospital stay is 2 days.

When entering for surgery, according to the algorithm of the clinical pathway, measures to cleanse the rectum with laxatives, enemas with intake of more liquids must be carried out. These measures are carried out in cases where emergency intervention is not necessary.

A doctor specializing in surgery, clinical laboratory and anesthesiology is needed to perform the operative intervention. If the hospitalized person is under 18 years of age, then a specialist in pediatric surgery is also needed.

Prevention and how to protect ourselves

  • Observing the principles of proper nutrition;
  • Timely treatment of paraproctitis;
  • We should not self-medicate in inflammatory diseases of the gastrointestinal tract;
  • Avoid trauma to the rectum, which can occur if hemorrhoids are left untreated;
  • Seek medical help for symptoms that may to cause anxiety.

How long does the healing process take

In the first week after the surgical intervention, a moderate pain syndrome is possible, which can be controlled with painkillers. The period during which sick leave is required is a maximum of one month.

After the surgical treatment of the fistula, a period of treatment at home is necessary with application of baths to the buttocks 3-4 times a day. More fiber-rich foods or laxatives are recommended.

To prevent contamination of underwear ordinary dressings can be used. Normal bowel movements do not affect wound healing in any way.

After the intervention, emphasis should be placed on foods rich in fiber to prevent stool hardening, which can lead to further traumatization of the area around the anus, as well as the lower part of the rectum. This would lead to an increase in the pain syndrome.

What are the chances of anal fistula recurrence

Provided proper healing, the risk of recurrence and re-formation of fistulas is minimal, however it is necessary to follow medical advice recommendations of the surgeon who performed the intervention.

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