What is a fistula? Everything you need to know about fistulas

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What is a fistula? What is an anal fistula?

A fistula is an abnormal connection between two organs or structures in the body that are not normally connected. Fistulas typically form around the anus but can occur anywhere in the body. These tunnel-like connections can appear, for example, between the skin and the intestines or between the bladder and the vagina.

A fistula is an abnormal connection or tunnel between two organs, blood vessels, or structures in the body that are not normally connected. These passages usually form as a result of injury, infection, inflammation, or surgery. Fistulas can develop in various parts of the body and, if left untreated, can lead to fluid leakage, chronic infections, or other complications. When fistulas appear in or around the anus, they are called anal fistulas.

An anal fistula is a special type of fistula that develops between the inside of the anal canal and the skin surrounding the anus. Fistulas can occur due to infection, trauma, various intestinal diseases, surgical procedures, or abscesses. Anal fistulas usually begin with an infection in one of the anal glands and form an abscess. When the abscess drains or is surgically opened, a tunnel may remain, which can lead to a fistula. Anal fistulas can cause pain or persistent discharge. Complete healing of these fistulas typically requires surgical treatment.

What are the types of fistulas?

Fistulas are abnormal connections between two parts of the body that are not normally connected. When they occur, they can interfere with normal body functions in various ways, depending on their location. While some fistulas are intentionally created for medical purposes, most arise as complications from infection, trauma, or surgery and require treatment.

The most common types of fistulas diagnosed and treated by healthcare providers include the following:

• Anal fistula: This occurs as an abnormal passageway from the inside of the anal canal to the skin around the anus. This type of fistula usually develops when an infection in the anal glands leads to a perianal abscess. Conditions such as Crohn’s disease and other inflammatory diseases can increase the risk. Symptoms are usually pain, swelling, and persistent discharge around the anus.
• Arteriovenous (AV) fistula: This type of fistula occurs when there is a direct connection between an artery and a vein. Some AV fistulas are intentionally created in people with kidney failure to provide access for dialysis, while others may result from injury or congenital conditions. Unwanted AV fistulas can disrupt normal blood flow and require intervention.
• Aortoenteric fistula: This rare fistula forms as an abnormal passageway between the aorta and the small intestine. It can result from an aortic aneurysm, infection (such as tuberculosis or syphilis), or previous aortic surgery. These fistulas can cause severe gastrointestinal bleeding and may be life-threatening. They require urgent surgical intervention.
• Perilymphatic fistula: This occurs when the membrane separating the middle ear from the inner ear ruptures. As a result, fluid from the inner ear leaks into the middle ear, affecting the person’s balance and hearing. These fistulas can occur after head trauma, barotrauma (pressure-related injuries), or surgical complications. Treatment varies depending on the severity of the condition, ranging from bed rest to surgical intervention.
• Tracheoesophageal fistula (TEF): A TEF is a congenital or acquired connection between the trachea (windpipe) and the esophagus. Congenital TEF is usually diagnosed shortly after birth, while acquired forms may result from cancer, surgery, or infection. TEF can cause serious feeding and breathing problems and requires urgent surgical repair.
• Vaginal fistula: A vaginal fistula is an abnormal connection between the vagina and a nearby organ, such as the bladder (vesicovaginal fistula), rectum (rectovaginal fistula), or intestine. One of the best-known subtypes is the obstetric fistula. These are among the most common fistulas in women. These fistulas can cause physical and emotional discomfort by allowing urine or feces to leak into the vaginal canal.
• Enterocutaneous fistula: This type of fistula usually results from abdominal surgery, trauma, or conditions such as Crohn’s disease, forming a connection between the intestines and the skin. Intestinal contents can leak through the skin, increasing the risk of infection and malnutrition.
• Mucus fistula: In some surgical situations, particularly after colostomy or ileostomy, surgeons may intentionally create a mucus fistula to redirect the intestine. This fistula may be temporary or permanent. It serves a functional medical purpose, particularly in helping to manage waste in certain parts of the intestine or reduce pressure.

The types of fistulas mentioned above do not cover all types of fistulas, but only list the most common ones. Each fistula, which differs depending on its location, requires a different treatment approach. Some fistulas are small and may resolve on their own. However, the majority require surgical or other medical interventions to restore body functions and prevent complications. Therefore, accurate diagnosis of the type of fistula is crucial for prompt and appropriate medical intervention.

What causes fistulas?

Although some fistulas are congenital, they are mostly caused by various events that lead to inflammation, infection, or tissue damage. For example, fistulas between the vagina and the bladder in women can develop as a result of injuries caused by hysterectomy. Diseases such as Crohn’s disease can also cause fistulas. In addition, abscesses filled with various human fluids that do not heal for a long time can extend to another tissue and form a fistula. The location of the fistula in the body and how it progresses determines its severity.

The most common causes of fistula formation are as follows:

• Infections: Long-term infections, especially abscesses, can damage tissues and lead to fistula formation. This condition is commonly seen in anal and perianal fistulas.
• Surgery or trauma: Surgical procedures involving the abdomen or pelvic area can inadvertently cause fistulas to form. Accidents or injuries that cause tissue damage can also contribute to this.
• Chronic inflammatory diseases: Conditions such as Crohn’s disease, ulcerative colitis, or diverticulitis can cause long-term inflammation and increase the risk of developing internal or external fistulas. Certain sexually transmitted diseases and conditions such as tuberculosis can also cause fistulas.
• Cancer and radiation therapy: Tumors can damage surrounding tissues and create abnormal connections, while radiation can weaken tissues and make them more susceptible to fistula formation.
• Obstetric complications: Prolonged or difficult births, especially in areas with limited medical resources, can lead to obstetric fistulas such as vesicovaginal or rectovaginal fistulas.

While some fistulas develop quickly, others may take time to develop and often begin as small abscesses that can develop into chronic channels.

What are the symptoms of a fistula?

The symptoms of a fistula can vary depending on the type of fistula, its location in the body, and its size. Fistulas, by their nature, involve an abnormal connection between two areas of the body. The symptoms that may be observed in a person, such as discomfort or dysfunction, may vary depending on the type of connection. Symptoms that start mildly may intensify over time, depending on the type of connection, and may continue with symptoms such as pain, discharge, foul odor, fever, and swelling.

Common types of fistulas and their associated symptoms are listed below:

• Anal fistula: These types of fistulas usually occur around the anus and cause pain, especially during bowel movements. Other common symptoms include constant pus or blood discharge from the anal area, skin irritation, and recurring abscesses. A visible opening or swelling near the anus may also be noticeable.
• Urinary tract fistula (e.g., vesicovaginal, ureterovaginal): These fistulas usually cause continuous or uncontrollable urine leakage from the vagina or other unwanted pathways. The person may experience urinary incontinence, frequent urinary tract infections, or discomfort during urination or sexual intercourse.
• Enterocutaneous fistula (intestine to skin): Symptoms of this type of fistula are usually the leakage of intestinal contents (fluid or stool) through the skin. Infection, malabsorption, dehydration, and electrolyte imbalance may also occur.
• Arteriovenous fistula: When an artery is abnormally connected to a vein, symptoms may include swelling, redness, or a pulsating mass. In some people, symptoms may also include fatigue, heart complications, or decreased blood flow to the extremities.
• Rectovaginal fistula: These fistulas usually occur after injuries during childbirth or as complications of inflammatory bowel disease. Rectovaginal fistulas can cause gas or stool to pass through the vagina, leading to infection and irritation.
• Vesicovaginal fistula: This type of fistula is characterized by a constant leakage of urine into the vaginal canal, causing odor, irritation, and social discomfort. These symptoms are usually persistent and unrelated to normal urination patterns.

Each type of fistula presents unique symptoms and complications depending on its location in the body. Therefore, proper diagnosis and effective treatment are crucial. If an individual experiences unexplained discharge, recurrent infections, or functional issues related to voiding or organ function, a fistula should be considered as a possible cause. In such cases, it is essential to consult a healthcare professional.

What is a urinary tract fistula?

In a urinary tract fistula, the fistula forms between the urinary system and another organ. This type of fistula typically causes unwanted urine leakage. These fistulas can affect the bladder, ureters, or urethra and often connect to the vagina, intestines, or skin.

One of the most common types of urinary fistula is the vesicovaginal fistula, in which urine leaks from the bladder into the vagina, causing constant urinary incontinence. Another type is the ureterovaginal fistula, in which the ureter is abnormally connected to the vagina.

These types of fistulas can result from gynecological surgery, radiation therapy, infections, or complications from traumatic childbirth. Symptoms of these fistulas may include urinary incontinence, recurrent urinary tract infections, discomfort or irritation during urination, or odor. Diagnosis of these fistulas typically requires imaging tests or cystoscopy. Treatment often involves surgical intervention and repair.

How is a fistula diagnosed?

The diagnosis of a fistula usually begins with a detailed medical history and physical examination. Depending on the suspected type and location of the fistula, doctors may use various diagnostic tools to confirm the diagnosis and assess the extent of the problem.

Some of the common methods used to diagnose fistulas include:

• Physical examination: This is helpful especially in external or anal fistulas, where the canal or opening can be seen.
• Imaging tests: MRI, CT scans, or ultrasound can help identify internal fistulas and monitor the extent of tissue involvement.
• Fistulography: A special X-ray procedure in which contrast dye is injected into the fistula, allowing the fistula tract to be seen more clearly.
• Endoscopy or colonoscopy: Helps detect fistulas in the gastrointestinal system.
• Cystoscopy: Used to examine the bladder in cases where a urinary tract fistula is suspected.

Accurate diagnosis is very important in selecting the correct treatment plan, as the treatment approach usually depends on the type, location, and severity of the fistula.

How is anal fistula treated?

Anal fistulas do not usually heal on their own. Therefore, treatment is necessary to restore bodily functions and prevent possible complications. Treatment for anal fistulas usually involves surgical intervention. The goal of treatment is to clean the infected tract while preserving anal function and preventing recurrence of the fistula.

Various surgical and minimally invasive procedures may be used, including:

• Fistulotomy: This is the most common method. The fistula tract is surgically opened and allowed to heal as a flat scar.
• Seton placement: In complex or high-risk cases, a surgical thread is placed into the fistula to facilitate drainage and support healing over time.
• Advanced flap procedure: A more advanced technique that uses healthy tissue to close the internal fistula opening and is beneficial for preserving continence.
• Fibrin adhesives or plugs: These are minimally invasive options that attempt to close the fistula without cutting tissue, but success rates may be lower.

The choice of which procedure to use during medical intervention depends on the complexity of the fistula, its location, size, and whether it passes through important muscles. Recovery usually involves wound care, pain management, and follow-up visits to ensure proper healing.