A gastrointestinal fistula (GIF) is an abnormal opening that allows gastric fluids to be discharged through the lining of the stomach, intestines, or colon. The discharge can leak into other organs or the skin, causing infection.
There are four main types of GIFs:
Also called a “gut-to-gut fistula,” this involves leaking from one part of the intestine into another where the folds touch.
Also called “cutaneous fistula,” this is when there is leaking through the skin.
This type involves both the internal organs and the skin.
GIF most often occurs after abdominal surgery. People with chronic digestive problems have a higher risk of developing a fistula. Treatment has improved in recent decades, but the mortality rate remains high: nearly 40 percent of those with high-output, post-surgery fistulas will not survive (Stawicki & Braslow, 2008).
Approximately 85 to 90 percent of GIFs develop after surgery (Stawicki & Braslow, 2008). Certain factors can increase a patient’s surgery-related risks:
- radiation treatment to the abdomen
- bowel obstruction
- surgery suture or incision-site problems
- abscess (infection) or hematoma (blood clot)
- poor nutritional status
Spontaneous GIF Formation
Spontaneous formation accounts for 10 to 15 percent of GIF cases. These can be caused by:
- inflammatory bowel diseases, such as Crohn’s disease—as many as 40 percent of Crohn’s patients develop a fistula at some point in their lives (Stein, et al., 2012)
- bowel infection (i.e., diverticulitis)
- vascular insufficiency (inadequate blood flow)
Although rare, physical trauma (such as gunshot or knife wounds that penetrate into the abdomen) can cause a GIF to develop.
External fistulas cause discharge through the skin. They are accompanied by other symptoms, including:
- abdominal pain
- painful bowel obstruction
- elevated white blood cell count
With internal fistulas, patients may also experience the following symptoms:
- rectal bleeding
- bloodstream infection, or sepsis
- poor absorption of nutrients and weight loss
- worsening of the underlying disease
The most serious complication of GIF is sepsis, an illness in which the body has a severe response to bacteria. This condition may lead to dangerously low blood pressure, organ damage, and death.
If you recently had surgery, contact your doctor right away if you experience:
- a significant change in your bowel habits
- severe diarrhea
- fluid leakage from an opening in the abdomen, or near the anus
- abdominal pain
To diagnose this condition, your doctor will first review your medical and surgical history, and assess your current symptoms. Initial blood testing may include:
- serum electrolytes (acid/base levels in the blood)
- nutritional status: this measures levels of albumin and prealbumin, proteins that play an important role in wound healing
If the fistula is external, the discharge may be sent to a laboratory for analysis. A fistulogram may be done by injecting contrast dye into the opening in the skin and taking X-rays.
Finding internal fistulas can be more difficult. The following tests may be done:
- upper and lower endoscopy: this procedure uses a thin, flexible tube with a camera attached (endoscope) to view possible problems in the digestive or gastrointestinal tract
- upper and lower intestinal radiography with contrast medium, including a barium swallow for suspected stomach or intestinal fistula. A barium enema may be used in the case of a suspected colon fistula
- ultrasound or computed tomography (CT) scan to find intestinal fistula or abscessed areas
- fistulogram: this test involves injecting a contrast dye into the opening of the skin in an external fistula and then taking X-ray images
For fistulae involving the biliary or pancreatic ducts, a specialized imaging test called magnetic resonance cholangiopancreatography (MRCP) may be used.
Resolving a GIF can take many months. Some fistulas may heal on their own within a few weeks or months. However, ongoing medical treatment may be necessary to manage symptoms or to prevent serious health complications. Treatment will depend on the severity of your condition.
Initial treatment may include:
- replenishing fluids
- correcting blood serum electrolytes
- normalizing acid/base imbalance
- reducing fistula fluid output
- controlling infection and guarding against sepsis
- protecting skin and providing ongoing wound care
Next, the fistula is tested and assessed. Treatment depends on the type of GIF, output level, and what organs are affected.
Several treatment options are available, including:
- hormones to reduce gastric fluid production
- lots of nutritional supplements
- surgery to close the fistula
Some types of fistula spontaneously close if the infection is controlled, and the body is absorbing enough nutrients.
People who are otherwise healthy generally make a full recovery.
Fistulas close on their own about 25 percent of the time, with conservative treatment (Stawicki & Braslow, 2008).
If the GIF will not heal on its own, surgery may be necessary. Surgery isn’t usually attempted until the patient has been treated for three to six months.