What is Intestinal Fistula?
A fistula is a sort of abnormal tunnel that forms between two surfaces lined by skin cells, although there are few exceptions. It is a term used to differentiate from sinuses and other similar conditions. A fistula actually creates a link between two distinct surfaces or spaces within the body. It usually begins at a particular site and then progressively extends to a nearby area or surface.
For instance, an intestinal fistula is a type of fistula that starts from the bowel. It could potentially reach out to a number of surrounding organs or surfaces. There are several kinds of intestinal fistulas including ones that connect the intestine to the skin, between intestines, between intestine and bladder, between intestine and colon, intestine and external environment, and between the rectum and vagina.
Fistulas are typically named based on the areas or organs they connect. The naming begins with the main organ where the fistula originates, and then the area or organ it connects to. So, a recto-vaginal fistula starts from the rectum and extends into the vagina, while an entero-cutaneous fistula starts from the small intestine and ends at the skin.
Intestinal fistulas can be tricky to handle surgically. The approach to assess, manage, and predict the outcome of the condition relies on how complex the fistula is and what caused it in the first place. This article will focus primarily on those fistulas that begin in the intestine, whether the small or large intestine. Specific types of fistulas will not be extensively discussed.
What Causes Intestinal Fistula?
Intestinal fistulas usually occur as a complication from a disease or surgical procedure rather than a disease on their own. Here is an explanation of the common causes of intestinal fistulas:
Surgical Procedure
Surgery is the leading cause of intestinal fistulas, accounting for more than half of all cases. However, the exact percentage can vary dramatically depending on factors like the patient’s overall health, the surgeon’s skills, and the complexity of the disease and surgical procedure. Despite this variability, it is recognized by practicing surgeons that surgical procedures can lead to intestinal fistulas.
Diverticular Disease
Diverticular disease, which causes pockets or bulges in the wall of your digestive tract, can sometimes lead to intestinal fistulas. This happens when the wall of a pocket wears down and inflammatory and abscessed matter spreads to nearby areas like the bladder wall, leading to the formation of a fistula. The fistula is maintained by pressure changes within the digestive tract and continuous inflammation.
Crohn’s Disease
Chronic digestive tract conditions, particularly Crohn’s disease, can also cause an intestinal fistula. Crohn’s disease can lead to various types of fistulas, which include between sections of the bowel, between the bowel and colon, between the bowel and bladder, between the bowel and skin, or around the anal area.
Malignancy
Cancer of the intestine or nearby organs can cause what’s known as a malignant fistula. This happens when the cancer spreads outward and inward, destroying normal tissue and creating an abnormal connection to nearby organs.
Radiation
Radiation treatment can cause long-term inflammation that delays your body’s healing and repair process, leading to the formation of an intestinal fistula sometimes years after radiation exposure.
Non-Surgical Injuries and Foreign Bodies
Injuries from accidents or foreign bodies entering the body can also cause an abnormal connection to form with the intestine.
There are also several known reasons for a fistula not to heal correctly that can be remembered with the acronym “FRIENDS”: Foreign body, Radiation, Inflammation, Epithelization (the creation of new skin), Neoplasm (tumor), Distal obstruction (blockage further down the digestive tract), or a Short fistula (a fistula that is shorter than normal). These factors don’t cause a fistula per se but can prevent one from healing properly. If an intestinal fistula doesn’t heal even after the proper treatment, it could indicate the presence of these factors and may require additional investigation.
Risk Factors and Frequency for Intestinal Fistula
The frequency of a condition called intestinal fistulae can change based on various factors. Fistulae are essentially abnormal connections between two parts inside the body. Factors that can affect the occurrence of fistulae include:
- The commonness and type of the underlying disease
- The quality and type of surgical treatment
- The quality of healthcare received
- The chances of experiencing physical trauma
- The use of medical treatment procedures like radiation
In places where Crohn’s disease, a gastrointestinal condition, is common, instances of intestinal fistulae tend to go up. This condition is also more common in areas of war or disaster due to the likelihood of serious abdominal injuries. Countries with poor quality healthcare, especially with complications from childbirth, often see more cases related to the pelvic area.
The occurrence of fistulae in terms of age, gender, and race matches the patterns of the underlying disease it comes from. Unfortunately, in places with low-quality healthcare and surgical practices, there are higher rates of sickness and death related to intestinal fistulae.
Signs and Symptoms of Intestinal Fistula
Intestinal fistulas may cause symptoms that provide clues to the underlying disease and any complications that may have arisen. These symptoms can vary widely, depending on the specific disease that caused the fistula. It’s important to note that in the early stages following a surgical procedure, symptoms related to an intestinal fistula can be more severe and, in some cases, life-threatening. Changes in vital signs and severe abdominal pain are common during this stage. Explicit examination of the details of any surgical procedures can help shed light on the condition if the original surgeon is not available to provide insights.
Common symptoms associated with intestinal fistulas can include:
- Abdominal pain
- Diarrhea
- Fever
- Bleeding in the gastrointestinal tract
- Weakness
- Lack of appetite
- Weight loss
In addition, specific symptoms related to the organ involved in the fistula may also be noted, such as:
- Frequent urinary tract infections, air bubbles or fecal matter in urine for entero-vesical fistula (link between intestines and bladder)
- Vaginal pain, discharge, and recurrent infections in recto- or colo-vaginal fistula (link between intestines and vagina)
- Skin pain, irritation, and skin damage around the fistula in entero- or colo-cutaneous fistula (link between intestines and skin).
Testing for Intestinal Fistula
If your doctor suspects you might have an intestinal fistula, there are different ways to analyze what’s going on based on whether it’s a slow-developing (chronic) fistula or one that’s come up suddenly (acute). Chronic fistulas, like those linking the colon and bladder, or the rectum and vagina, can be checked on in recurring outpatient appointments. The goal of these evaluations is to confirm the diagnosis, find out more about the fistula, like its location and size, determine what might have caused it if it’s unclear, plan for how to manage it, and check how it’s progressing over time.
On the other hand, a sudden, severe intestinal fistula – such as one that happens after surgery – needs to be identified and evaluated right away to confirm the suspicion and understand the extent of the complication.
After a detailed medical history review and physical exam, there are various ways available for your doctor to further evaluate the condition:
Imaging: An imaging procedure, using a special dye that travels through the fistula, can provide a clear picture of where it’s located and how extensive it is. This dye might not always appear in the fistula but could be seen in the organ that the fistula connects to, like the bladder or vagina. Common ways of achieving this include a small bowel follow-through or a contrast enema. CT scans, which can provide highly detailed images, are often the first step, especially for a sudden fistula. These results are essential for planning any necessary surgical treatment. In cases where the fistula is hard to pin down, an MRI could be helpful. This provides a better look at the soft tissues and can be especially useful for complex cases like those associated with Crohn’s disease.
Endoscopy: Procedures like colposcopy, cystoscopy, gastroduodenostomy or colonoscopy can help your doctor see the site of the fistula on the organ lining’s surface. The presence of a small inflamed, red, and potentially raised area on the organ lining could be a sign of a fistula. It is commonly challenging to clearly see the fistula itself, unless it’s especially large. An endoscopy could provide additional information about the underlying cause of the fistula, like cancer or Crohn’s disease. Sometimes fistulas might be found incidentally during an endoscopy done for other reasons. If that’s the case, your doctor has to do more tests.
Treatment Options for Intestinal Fistula
A fistula is an abnormal connection between two parts of the body. For example, an entero-vesical fistula is a pathway that has incorrectly formed between the intestines and the bladder. When it comes to treating a fistula, the goal is twofold: address the fistula itself and treat its root cause (the underlying disease).
It’s important to figure out what caused the fistula before starting any treatments. There are several factors to consider when deciding on the best treatment plan, including the severity of the condition, the specific type of fistula, the patient’s overall health, the underlying cause of the fistula, and any complications that have arisen from the fistula.
Non-Surgical Approach
Patients with a high risk or severe underlying disease might start with a non-surgical treatment plan. This approach typically involves managing symptoms and potential complications like urinary tract infections (UTIs), skin irritation, dehydration, or infections around the fistula’s location. Non-surgical treatment may also involve medical treatment of the underlying disease, like maximising medications for Crohn’s disease or diverticulitis, and focusing on overall patient health. In certain cases, other non-surgical methods may be used to try and close the fistula, such as the application of a special glue.
Surgical Approach
In other cases, surgery may be necessary. This usually involves removing the part of the bowel that’s attached to the fistula, and the fistula itself. The specific surgical plan will depend on the diagnosis of the fistula and the underlying disease. This could range from a conservative removal of the affected part of the intestine and the fistula for conditions like Crohn’s disease or diverticulitis, to a more comprehensive removal for cancers that can be treated surgically. Depending on the situation, the fistula might be found during the surgery for the underlying disease. If this happens, and it’s not a cancer case, the surgical approach would typically stay the same.
In the case of an entero-cutaneous fistula (one that leads to the skin), the treatment might be slightly different. The focus is on the part of the intestine where the leak started, and the fistula is treated as part of this process. If non-surgical treatments haven’t worked, and after medically optimising the patient, the surgeon will plan to remove the affected part of the intestine. This is followed by the cleaning and draining of the fistula as part of the procedure. It’s crucial to clean away all unhealthy tissue and close the area with healthy tissue to achieve successful healing and fistula closure.
What else can Intestinal Fistula be?
These are some of the different conditions that could cause similar symptoms as an abdominal problem:
- Abdominal abscess (buildup of pus in the abdomen)
- Abdominal aortic aneurysm (an enlarged area in the lower part of the large blood vessel that supplies blood to the body)
- Aortitis (inflammation of the aorta)
- Appendicitis (inflammation of the appendix)
- Blunt abdominal trauma (injury to the abdomen)
- Colon cancer
- Cystitis (bladder inflammation)
- Diverticulitis (inflammation or infection of small pouches that can form in your intestines)
- Enterovesical fistula (an abnormal connection between the bladder and the intestine)
- Inflammatory bowel disease (conditions like Crohn’s disease and ulcerative colitis, which cause chronic inflammation in the digestive tract)
