History and Physical Examination
The clinical presentation of the various forms of intestinal fistulas depends on the organs involved. The predominant signs and symptoms are those of infection from intestinal bacterial contamination.
Enterocutaneous fistulas
Excessive drainage via the abdominal incision or via operatively placed drainage catheters is often the first indicator of a postoperative enterocutaneous fistula. The drainage typically consists of obvious intestinal contents or fluid with bile staining (see the image below). The presence of purulent fluid may disguise the character of the intestinal fluids, leading to initial misdiagnosis of a wound infection. The presence of gas bubbles in the wound or drain output also indicates an intestinal connection. If differentiation proves difficult, the patient may be given oral methylene blue, indigo carmine, or activated charcoal. The presence of these substances in the drainage confirms the presence of an intestinal leak.
The skin surrounding the area of the fistula is erythematous and indurated and may be fluctuant if an underlying collection is present.
Clinical signs of sepsis (eg, fever, tachycardia, chills) are common when the fistula is associated with undrained intraperitoneal abscesses and infection of the soft tissue of the abdominal wall.
Enteroenteric fistula
Radiologic studies are often used for initial diagnosis of enteroenteric fistulas. The studies are obtained to evaluate intestinal symptoms or abdominal pain. Diarrhea, abdominal pain, weight loss, and fever are common symptoms associated with enteroenteric fistulas of all etiologies.
Enteroenteric fistula symptoms are nonspecific and may be due to the underlying disease process (eg, Crohn enteritis, radiation enteritis) or the presence of the fistula. Abdominal tenderness may be present on physical examination. Occasionally, a palpable abdominal mass representing densely adherent bowel loops is present.
Enterovesical fistula
Urinary tract contamination with intestinal organisms leads to the development of urinary symptoms in more than 80-90% of patients with enterovesical fistulas. The common presenting urinary symptoms include bladder irritability, dysuria, pyuria, fecaluria, and pneumaturia. Fulminant urosepsis may develop, especially in patients who are immunocompromised from underlying disease or immunosuppressant medications. (See the image below.)
Nephroenteric fistulas
Typically, nephroenteric fistulas (see the image below) develop slowly because of chronic renal disease; thus, the most common initial symptom is chronic urinary tract infection. In contrast, nephroenteric fistulas that occur from penetrating trauma often present early with symptoms of urinary tract infection.
Patients may have flank pain, tenderness, and a mass. As the fistula becomes established, fecaluria, pneumaturia, fever, chills, and fulminant sepsis develop. A watery diarrhea can occur, and, in the late stages, severe dehydration, uremia, and acidosis develop. Function of the affected kidney is rarely normal. Perinephric abscesses are common and may cause a mass effect, leading to further deterioration of function.
Enterovaginal fistulas
Purulent or feculent vaginal discharge is the most common presentation of enterovaginal fistula (see the image below). Sepsis from associated intraperitoneal abscesses is common, and these patients experience abdominal pain, fever, and chills. Patients may develop a urinary tract infection because of bacterial contamination ascending the urethra.
Aortoenteric fistula
Aortoenteric fistulas (see the image below) present with gastrointestinal (GI) bleeding because of a direct communication between enteric lumen (commonly duodenum and the arterial lumen). Initial herald or sentinel bleeding (eg, hematemesis, hematochezia, melena) is commonly mild and self-limited. Often weeks to months later, the patient has an episode of massive GI hemorrhage.
Aortoenteric fistula demonstrating a direct connection between the intestinal lumen (typically the duodenum) and the prosthetic graft.
Patients with a paraprosthetic-enteric fistula (see the image below) have a perigraft abscess or an aneurysm that communicates with the intestinal lumen. Sepsis and abdominal pain are observed on initial presentation. If the infection remains untreated, eventually a communication develops between the arterial and intestinal lumen and GI hemorrhage occurs.
Aortoenteric fistula that forms through erosion of a periprosthetic graft infection into the intestinal lumen.
Subclinical ongoing bleeding leads to chronic anemia. A patient with an aortic prosthetic graft and evidence of either acute or chronic GI hemorrhage must have an aortoenteric fistula unless definitive proof to the contrary is available.
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Classification of fistulas.
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Management algorithm for intestinal fistulas.
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Predictive factors for spontaneous closure and mortality associated with fistulas.
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Postoperative enterocutaneous fistula. Fistula forms as a result of partial or complete intestinal anastomotic disruption and associated resultant abscess.
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Congenital patent omphalomesenteric duct resulting in an enterocutaneous fistula.
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Enterovesical fistula.
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Nephroenteric fistula.
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Enterovaginal fistula.
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Aortoenteric fistula demonstrating a direct connection between the intestinal lumen (typically the duodenum) and the prosthetic graft.
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Aortoenteric fistula that forms through erosion of a periprosthetic graft infection into the intestinal lumen.
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Enterocutaneous fistula output is controlled through placement of a soft-sump drain into the cutaneous opening of the fistula tract. The sump drain is connected to low suction, and the fistula opening and drain are contained within an ileostomy bag. An additional drain is placed within the bag and to continuous suction to keep the bag empty and to minimize the contact of surrounding skin with enteric contents.
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Bypass of fistulous bowel loops that are densely adherent within the pelvic cavity by creation of an anastomosis between the divided afferent limb and the transverse colon.
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Bypass of a densely adherent fistula by anastomosis of afferent and efferent limbs of intestine in continuity. This is an ineffective method of bypass, since the enteric contents continue to flow into the fistula tract.
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A densely adherent or unresectable fistula is bypassed by dividing both afferent and efferent intestinal loops and reanastomosing the divided ends to restore intestinal continuity. The fistula tract is essentially isolated from the enteric stream. If a longer loop of bowel is bypassed, the divided ends can be exteriorized.
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Enterocutaneous fistula.
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Enterocutaneous fistula.
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Resected enterocutaneous fistula, embedded in surrounding inflammatory tissue and skin.
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Stapled closure of intestinal lumen to restore intestinal continuity following resection of enterocutaneous fistula.
