If you’ve ever looked online for an explanation of a gastrointestinal problem like Crohn’s disease or ulcerative colitis, you may have come across the term fistula. But what is a fistula? In general terms, a fistula is an abnormal passageway that can form between two spaces within the body. More specifically, a fistula will only form in spaces lined with epithelial tissue, the bodily substance that acts as a covering for organs and body cavities.   

These ‘tunnels’ are typically an unwelcome development that will require a remedy, and they often come about because of an infection or inflammation in the tissue in question. There are some situations where a doctor might create a fistula for therapeutic purposes, as with some people who are on kidney dialysis. But for the most part, if you’ve got it, you don’t want it.  

Are there Different Types of Fistula?

As a general malady, a fistula can happen in many different places throughout the body. Different types of fistulas are categorized by the two parts of the body where they appear, and it’s possible for one to develop any place in the body with epithelial cell linings. 

The most typical locations, however, are between the tissues involved in the digestive system and other nearby organs - often the organs of the reproductive system. Here are some of the most common fistulas:  

  • Anorectal fistula: between the anal canal and the skin surrounding the anus
  • Anovaginal fistula: between the anal canal and vagina
  • Colovaginal fistula: between the vagina and colon
  • Colocutaneous fistula: between the colon and the epidermis
  • Enteroenteral fistula: between two different parts of the small intestine 
  • Enterocutaneous fistula: between the small intestine and the epidermis 
  • Rectovaginal fistula: between the rectum and vagina 
  • Urethrovaginal fistula: between the urethra and vagina 
  • Vesicouterine fistula: between the bladder and uterus
  • Vesicovaginal fistula: between the bladder and vagina 

With all of these common types of fistula related to the digestive system, a gastroenterologist will be the primary type of physician who would diagnose and treat the condition.  

What are the Symptoms of a Fistula?

The symptoms of a fistula will vary depending on the type and location. For example, a fistula between different parts of the large and small intestines will typically cause diarrhea and cause the stool to contain undigested food. 

By contrast, symptoms of a fistula occurring between the intestines and the bladder may include a urinary tract infection. Additionally, you may experience a burning sensation while urinating, and your urine might be cloudy or contain blood. A fistula between the intestines and vagina might cause stool or gas to be passed through the vagina, whereas a fistula between the intestines and skin may show up like a boil or abscess that drains stool or fluid. 

The most common fistulas tend to occur in and around the anus, so the symptoms to be on the lookout for are inflammation, swelling, or pain around the anus. You may also notice a lump at first at the site of the opening of the fistula; these lumps can open and begin oozing foul-smelling fluids such as pus, blood, or stool. In some cases, you might also have a fever or experience bleeding or pain when passing stool. 

What Causes an Anal Fistula?

There are any number of causes for fistulas throughout the body, but anal fistulas very often develop in those who have an inflammatory bowel disease (IBD) like Crohn’s disease or ulcerative colitis. 

The nature of Crohn’s disease, for example, involves severe inflammation of parts of the gastrointestinal tract. Chronic inflammation of the intestines (or other parts of the digestive system) can lead to the creation of ulcers in the epithelial lining. Sometimes these infected ulcers grow and expand through the whole thickness of the intestines and will eventually form a tunnel (the fistula) in order to drain fluid from the infection; the tunnel eventually makes its way outside the intestine to another area. In the case of an anal fistula, this tunnel leads to the skin surrounding the anus.  

The same kind of thing can happen with ulcerative colitis (or other inflammatory bowel diseases); an ulcer forms that will become clogged and unable to drain pus inside the colon. The fistula then forms in order to drain the pus elsewhere. One example mentioned earlier was the colovaginal fistula, where the tunnel leads from the colon to the vagina and can drain pus as well as fecal matter into the vagina. 

Simple and Complex Fistulas

Anal fistulas also can be categorized into two types, depending on their location vis-a-vis the internal or external sphincter muscles in the anal canal. For reference, the internal anal sphincter is a smooth muscle that involuntarily controls the passage of waste materials; the external sphincter is another smooth muscle wrapped around the internal sphincter and is voluntarily controlled. 

One type of anal fistula is the simple fistula (also sometimes referred to as fistula-in-ano). This happens when a fistula develops below the sphincter muscles. This type has only one ‘tunnel.’ 

Another type is known as the complex fistula. As the name implies, the complex fistula is more complex, with more sphincter muscle involvement and a greater number of passageways. These also often include abscesses and/or are connected to the bladder. 

How Can I Manage My Fistula on a Day-to-day Basis? 

If you are diagnosed with a fistula, it is the kind of affliction that will need to be managed with the help of a doctor. Depending on the type of fistula a patient is diagnosed with, he or she may treat the fistula with medication or surgery. 

Generally speaking, simple fistulas can be treated with medication or a series of non-invasive procedures. In the case of inflammation due to an infection, antibiotics may be employed in order to treat the infection. But there are also a few procedures available:

  • Catheter: a small tube is inserted into the fistula in order to drain any fluid
  • Plug: a collagen matrix is used to fill the fistula 
  • Fibrin glue: this medical adhesive is used to seal the opening of the fistula

Complex fistulas, on the other hand, may very well require surgery in order to provide long term relief from the fistula. It has been estimated that a full third of Crohn’s disease patients with anal fistulas will end up requiring surgery. These surgeries are usually paired with medication for optimal results. Here are a few of the surgical options the doctor may consider: 

  • Setons: Divided into “loose” seton and “cutting” seton varieties, these surgical threads are inserted into the fistula throughout its length and promote healing/closure by promoting drainage of the fistula. (Some patients report that this can feel like a rubber band dangling from their anus.) 
  • Fistulotomy: This more invasive procedure can be used for simple fistulas or complex fistulas that don’t involve too much sphincter muscle. The surgeon will cut along the length of the fistula, thereby flattening it out and promoting eventual healing. 
  • Mucosal advancement flap procedure: A flap of the rectum is pulled down over the fistula opening to cover and encourage it to close. This is useful when there is greater sphincter involvement and surgery would pose a higher risk of resulting incontinence. 
  • Video-assisted anal fistula treatment (VAAFT): A newer technique, this method utilizes a small camera to visualize the fistula from inside. With greater visibility, the surgeon can use an electric current to cauterize the fistula opening.  

Fistula Appointment

Having a fistula is undoubtedly an unpleasant possibility, particularly if you’re already suffering from Crohn’s disease. The good news is that gastroenterologists now have a variety of excellent treatment options if you do end up getting diagnosed with a fistula.  If you have been experiencing any of the symptoms noted above, or if you think you may have an IBD or another digestive problem, feel free to contact Cary Gastroenterology. With an amazing staff that includes seven board-certified gastroenterologists and hepatologists, Cary Gastro will provide excellent health care.