A fistula is an abnormal passage or tunnel that forms in the body. This passage can exist between two internal organs (internal fistula) or between an internal organ and the external surface of the body (external fistula) [2] . The types of fistulas vary depending on their location and the organs they connect, which influences symptoms and treatment options. Common Types of Fistulas There are several types of fistulas, including: Colonic and Anorectal Fistulas: A colonic fistula is an abnormal tunnel that connects the colon to the skin surface or to another internal organ such as the bladder, small intestine, or vagina. An anorectal fistula is an abnormal tunnel connecting the anus or rectum to the skin surface around the anus [2] . In some cases, women may suffer from rectovaginal fistulas, which are anorectal fistulas that connect the anus or rectum to the vagina [2] . Arteriovenous Fistulas (AVMs): These fistulas are abnormal tangles of blood vessels that cause connection problems between arteries and veins. They usually occur in the spinal cord and brain, but can develop anywhere else in the body [1] . In this condition, blood flows directly from the arteries to the veins without passing through capillaries, depriving tissues of oxygenated blood [1] . Dural Arteriovenous Fistulas: These fistulas can occur in the membrane surrounding the brain and spinal cord. They are thought to originate from an injury to the membrane that creates a fistula between an artery and a vein in the membrane [1] . Causes of Fistulas The causes of fistulas vary depending on their type and location: Colonic and Anorectal Fistulas: These fistulas are often acquired and not present at birth [2] . The most common cause of colonic fistulas is abdominal surgery, while anal abscesses, resulting from infections of the anal glands, are the most common cause of anorectal fistulas [2] . Conditions such as Crohn's disease, diverticulitis, cancer, radiation therapy, or trauma can also cause these types of fistulas [2] . Arteriovenous Fistulas (AVMs): The cause of the formation of these fistulas is not fully understood. In most cases, they are congenital (present at birth), but they can appear shortly after birth or later in life [1] . It is believed they are often the result of problems that occur during development in the womb [1] . Symptoms of Fistulas Symptoms of a fistula depend on its location and type: Colonic Fistula Symptoms: May include the passage of fluid, stool, or gas through an opening in the skin, in the urine, or through the vagina [2] . If the fistula connects the colon to another part of the intestine, it may cause symptoms such as diarrhea, abdominal pain, and weight loss [2] . In some cases, colonic fistulas may not cause any symptoms [2] . Anorectal Fistula Symptoms: May include discharge of pus from an opening in the skin around the anus, swelling and pain near the anus that may come and go, sometimes with redness or fever, and anal pain [2] . In women, a rectovaginal fistula may cause the passage of stool or gas through the vagina [2] . Arteriovenous Fistula (AVM) Symptoms: Symptoms can be mild or severe and may include seizures, headaches, visual problems, muscle weakness, speech difficulties, movement problems, abnormal sensations such as numbness or tingling, cognitive difficulties, dizziness, and loss of consciousness [1] . The greatest risk posed by these fistulas is bleeding, which can be significant and may lead to a stroke and brain damage [1] . Diagnosis and Treatment of Fistulas The diagnosis of fistulas relies on symptoms, medical history, physical examination, and imaging tests [2] . Imaging tests may include ultrasound, lower gastrointestinal series (barium enema), computed tomography (CT), magnetic resonance imaging (MRI), and fistulography [2] . You can learn more about various fistulas: their causes, symptoms, diagnosis, and surgical treatment (Arabic) . Regarding treatment, some colonic fistulas may heal on their own without surgery, as doctors focus on treating or preventing any complications to help the fistula heal [2] . This may include administering fluids and electrolytes, nutritional support, antibiotics, and draining any abscesses [2] . However, most anorectal fistulas usually require surgery [2] . In the case of arteriovenous fistulas, treatment depends on their type, location, symptoms, and the individual's general health [1] . Medications can alleviate general symptoms such as headaches, back pain, and seizures [1] . When should you seek emergency care? If you are experiencing severe symptoms such as heavy bleeding, sudden and severe headache, seizures, sudden weakness on one side of the body, or loss of consciousness, especially if you know you have an arteriovenous fistula, you must seek emergency medical care immediately [1] . These symptoms may indicate dangerous internal bleeding. Medical references Colonic & Anorectal Fistulas Arteriovenous Malformations (AVMs)

What is a Fistula? Types, Causes, Symptoms, and Treatment

A fistula is an abnormal passage or tunnel that forms in the body. This passage can exist between two internal organs (internal fistula) or between an internal organ and the external surface of the body (external fistula) [2]. The types of fistulas vary depending on their location and the organs they connect, which influences symptoms and treatment options.

Common Types of Fistulas

There are several types of fistulas, including:

Colonic and Anorectal Fistulas: A colonic fistula is an abnormal tunnel that connects the colon to the skin surface or to another internal organ such as the bladder, small intestine, or vagina. An anorectal fistula is an abnormal tunnel connecting the anus or rectum to the skin surface around the anus [2]. In some cases, women may suffer from rectovaginal fistulas, which are anorectal fistulas that connect the anus or rectum to the vagina [2].
Arteriovenous Fistulas (AVMs): These fistulas are abnormal tangles of blood vessels that cause connection problems between arteries and veins. They usually occur in the spinal cord and brain, but can develop anywhere else in the body [1]. In this condition, blood flows directly from the arteries to the veins without passing through capillaries, depriving tissues of oxygenated blood [1].
Dural Arteriovenous Fistulas: These fistulas can occur in the membrane surrounding the brain and spinal cord. They are thought to originate from an injury to the membrane that creates a fistula between an artery and a vein in the membrane [1].

Causes of Fistulas

The causes of fistulas vary depending on their type and location:

Colonic and Anorectal Fistulas: These fistulas are often acquired and not present at birth [2]. The most common cause of colonic fistulas is abdominal surgery, while anal abscesses, resulting from infections of the anal glands, are the most common cause of anorectal fistulas [2]. Conditions such as Crohn's disease, diverticulitis, cancer, radiation therapy, or trauma can also cause these types of fistulas [2].
Arteriovenous Fistulas (AVMs): The cause of the formation of these fistulas is not fully understood. In most cases, they are congenital (present at birth), but they can appear shortly after birth or later in life [1]. It is believed they are often the result of problems that occur during development in the womb [1].

Symptoms of Fistulas

Symptoms of a fistula depend on its location and type:

Colonic Fistula Symptoms: May include the passage of fluid, stool, or gas through an opening in the skin, in the urine, or through the vagina [2]. If the fistula connects the colon to another part of the intestine, it may cause symptoms such as diarrhea, abdominal pain, and weight loss [2]. In some cases, colonic fistulas may not cause any symptoms [2].
Anorectal Fistula Symptoms: May include discharge of pus from an opening in the skin around the anus, swelling and pain near the anus that may come and go, sometimes with redness or fever, and anal pain [2]. In women, a rectovaginal fistula may cause the passage of stool or gas through the vagina [2].
Arteriovenous Fistula (AVM) Symptoms: Symptoms can be mild or severe and may include seizures, headaches, visual problems, muscle weakness, speech difficulties, movement problems, abnormal sensations such as numbness or tingling, cognitive difficulties, dizziness, and loss of consciousness [1]. The greatest risk posed by these fistulas is bleeding, which can be significant and may lead to a stroke and brain damage [1].

Diagnosis and Treatment of Fistulas

The diagnosis of fistulas relies on symptoms, medical history, physical examination, and imaging tests [2]. Imaging tests may include ultrasound, lower gastrointestinal series (barium enema), computed tomography (CT), magnetic resonance imaging (MRI), and fistulography [2]. You can learn more about various fistulas: their causes, symptoms, diagnosis, and surgical treatment (Arabic).

Regarding treatment, some colonic fistulas may heal on their own without surgery, as doctors focus on treating or preventing any complications to help the fistula heal [2]. This may include administering fluids and electrolytes, nutritional support, antibiotics, and draining any abscesses [2]. However, most anorectal fistulas usually require surgery [2]. In the case of arteriovenous fistulas, treatment depends on their type, location, symptoms, and the individual's general health [1]. Medications can alleviate general symptoms such as headaches, back pain, and seizures [1].

When should you seek emergency care?

If you are experiencing severe symptoms such as heavy bleeding, sudden and severe headache, seizures, sudden weakness on one side of the body, or loss of consciousness, especially if you know you have an arteriovenous fistula, you must seek emergency medical care immediately [1]. These symptoms may indicate dangerous internal bleeding.

What is a fistula?