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Basics of Anal Fistulas


  An anal fistula is the formation of an abnormal channel between the muscle of the anus, called the anal sphincter, and the inside of the large intestine. According to The Association of Coloproctology of Great Britain and Ireland, “the majority of fistulas unrelated to specific causes such as Crohn’s disease result from infections in anal glands.” (1)


  This condition affects the patient’s life, the only effective treatment involves surgery. Sphincters are circular shaped muscles that open and close certain channels of our body. We actually find them everywhere, the upper and lower esophagus, in blood vessels and of course the anus.


  We can differentiate between different subtypes of anal fistulas depending on the location in which they are present:

  • Extrasphincteric: the fistula does not pass through muscles of the sphincter
  • Suprasphincteric: appears above the anal sphincter
  • Intersphincteric: crosses the internal sphincter musculature
  • Transsphincteric: begins right in between the external and internal muscles of the sphincter and makes its way outwards, crossing over the external musculature of the anal sphincter.


  The symptoms that patients present more frequently when suffering from an anal fistula are:

  • Pain or discomfort that varies in intensity. It can occur in the abdominal area due to peristaltic movements or in the anal region. This discomfort is accentuated when the lesions are closer to the anus and performing certain actions. For example, sitting down or going to the bathroom.
  • Irritation of the perianal area. Because fistulas connect the digestive tract to the outside, anal mucus and fecal material can be released at their ends. Accumulation of pus can be formed in this region. When these substances come into contact with the sensitive skin of the area, it becomes irritated.
  • High fever. It occurs in patients who have an infection.


  We can also point to some medical conditions that favor the development of anal fistulas:

  • Presence of anal abscesses that store pus. They are produced by infection of the area that normally occurs in the glands that secrete mucus into the digestive tract. When they become clogged, an accumulation of pathogens begins to build up, causing an infection.
  • Crohn’s disease and ulcerative colitis. In them the patient suffers injuries along the large intestine that produce their inflammation.
  • Sexually transmitted diseases or STDs.
  • Injuries or traumatisms.
  • Pathologies that alter the immune system.
  • Vascular or hematological disorders.
  • Other diseases such as cancer, diabetes, tuberculosis, etc.


Diagnostic Methods


  To identify this pathology and discard other disorders, your doctor or specialist can recommend and perform a series of tests such as a physical exam where the doctor can view the perianal area to confirm if the anal fistula connects with the external environment and also check if there is an accumulation of pus in it. An endoscopy (using a thin cable that has a camera at one end) can be performed so they can observe the location and length of the anal fistula. An abdominal ultrasound, to obtain the image of the path taken by the fistula inside the intestinal tract. Other common medical tests can be done to determine if there is an underlying disease. For example, blood tests, urine tests, etc.


  Your physician may also order the use of certain medications or habits to relieve certain symptoms and improve quality of life. However, the most effective treatment is the performance of a surgical intervention where surgeons will examine the depth of the fistula and what is the best technique to follow. After the operation, the patient can gradually continue his or her daily life as long as they follow the postoperative recommendations given by the medical professional.


  Commonly, abscesses occur from the infection of anal fissures. The fissures are small cuts that can be produced by constipation or continued diarrhea of the patient. Therefore, it is advisable to adopt a healthy diet rich in fiber and avoiding foods that can irritate our intestines. We also must maintain adequate anal hygiene and perform moderate physical activity. Physical exercise favors the movements that occur in our intestines (peristaltic movements).


  If you suspect anal fistula or any other pathology, do not hesitate to consult with your medical team since there are diseases that camouflage themselves behind similar alterations. That is why early diagnosis is crucial.


(1) The Association of Coloproctology of Great Britain and Ireland. “Anal abscess and fistula.” Retrieved from


Robert Velasquez
25 April, 2019

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Hello everyone, my name is Robert Velazquez. I am a content marketer currently focused on the medical supply industry. I studied Medicine for 5 years. I have interacted with many patients and learned a more:

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