|REVIEW ARTICLE: REPUBLICATION
|Year : 2017 | Volume
| Issue : 3 | Page : 77-81
Stanislaw P Stawicki1, Benjamin M Braslow2
1 OPUS 12 Foundation, Bethlehem, PA, USA
2 OPUS 12 Foundation, Bethlehem; Department of Surgery, Division of Traumatology and Surgical Critical Critical Care, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
|Date of Web Publication||21-Apr-2017|
Stanislaw P Stawicki
Department of Surgery, St. Luke'fs Hospital and Health Network, 801 Ostrum Street, Bethlehem, PA 18015
Source of Support: None, Conflict of Interest: None
Key points: (a) Gastrointestinal fistulae (GIF) continue to be associated with high morbidity and mortality; (b) Approximately 85% to 90% of GIF result from surgical procedures; (c) Spontaneous GIF (10% to 15%) most commonly result from inflammatory bowel disease, malignancy, and infection (i.e., diverticulitis); (d) Fistula classification and natural behavior are discussed; followed by (e) Discussion of diagnostic and treatment principles, as well as special issues encountered in GIF management.
The following core competencies are addressed in this article: Medical knowledge and patient care.
Republished with permission from: Stawicki SP, Braslow BM. Gastrointestinal fistulae. OPUS 12 Scientist 2008;2(1):13-16.
Keywords: Complications of surgery, gastrointestinal fistula, inflammatory bowel disease, review
|How to cite this article:|
Stawicki SP, Braslow BM. Gastrointestinal fistulae. Int J Acad Med 2017;3, Suppl S1:77-81
| Introduction|| |
Despite significant medical and surgical progress over the last two decades, gastrointestinal fistulae (GIF) continue to be associated with high morbidity and mortality (nearly 40% with postoperative high-output fistulae).,,,
Approximately, 85% to 90% of GIF arise following surgical procedures. Gynecologic patients appear to be at an increased risk of GIF (up to 30%), mainly because of the high incidence of malignancy and associated aggressive therapeutic regimens. Urgent/emergent surgical procedures, foreign body close to the suture line, tension on the suture line, complex suturing patterns/techniques, distal bowel obstruction, hematoma or abscess near the anastomosis, tumor, under-resuscitation, and poor nutritional status all contribute to postoperative GIF formation [Table 1] and [Table 2].,,,,,
Spontaneous fistula development (10%–15% of cases) is most often attributed to inflammatory bowel disease, malignancy, infection (i.e., diverticulitis), vascular insufficiency/mesenteric ischemia, and radiation exposure.,,,
There are multiple reasons that account for the poor prognosis associated with GIF. These factors include: (a) frequent presence of associated severe systemic disease (malignancy, inflammatory bowel disease, etc.); (b) difficulty in maintaining adequate nutritional status; (c) frequent presence of ongoing systemic inflammatory response and/or sepsis; (d) associated severe fluid and electrolyte disturbances; and (e) often complex and difficult to manage wounds.,,,,,
| Definitions|| |
A fistula is defined as an abnormal communication between two epithelialized surfaces. GIF represent abnormal communications between the gastrointestinal tract and another epithelial-lined surface. The communication may involve the skin, another part of the gastrointestinal tract, or another organ system (biliary, respiratory, or genitourinary).
| Classification of Gastrointestinal Fistulae|| |
There are two broad classifications of GIF, congenital and acquired (focus of this review). Acquired fistulae include the following subtypes: (a) intestinal (gut-to-gut); (b) extraintestinal (involves genitourinary, biliary, vascular, respiratory, or other structures); (c) external or cutaneous (can be further divided into high- or low-output); and (d) complex fistulae (both internal and external).
| Natural Behavior of Gastrointestinal Fistulae|| |
Approximately, 70%–90% of GIF will close spontaneously if appropriately managed (see subsequent sections). Spontaneous closure is more likely if the following conditions are met: (a) bowel continuity is maintained; (b) there is no associated abscess; (c) the bowel defect is small (<1 cm in diameter); (d) the adjacent bowel is healthy and there is no distal obstruction; (e) the fistula tract is not epithelialized or more than 2 cm in length; and (f) there is no associated malignancy. Spontaneous closure rate also depends on the fistula location; while a colonic fistula may take 30–40 days to close, an ileal fistula may take 40–50 days [Table 1] and [Table 3].,,,,,,,
|Table 3: Important considerations when approaching gastrointestinal fistulae|
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External fistulae can be further classified into high-output (>500 mL/day in drainage) and low output (<500 mL/day in drainage) fistulae. In case of pancreatic fistulae, a high-output fistula is defined as one with >200–300 mL of drainage daily. Of note, high-output fistulae are likely to produce serious metabolic, fluid, and electrolyte disturbances. Mortality and morbidity are also increased with high-output fistulae.,,,,
Gastric, lateral duodenal, ligament of treitz, and ileal fistulae are least likely to spontaneously close. Therefore, these fistulae require the most aggressive medical therapy and are likely to require operative intervention [Table 2].,,,,,,,,
External fistulae are usually apparent when abnormal fluid/succus discharge appears. These GIF are often associated with abdominal pain and tenderness, ileus, fever, and elevated white blood cell count. The enteric character of the discharge is usually diagnostic. If the exact nature of drainage is unclear, the fluid may be sent for laboratory analysis (amylase, lipase, creatinine, bilirubin, etc.,), and radiographic contrast studies may be used to confirm the diagnosis, or a dye test (such as methylene blue) may be performed for confirmatory purposes [Table 3].,,,
Internal fistulae are usually more subtle in presentation than external fistulae. Symptoms of internal GIF may include diarrhea, rectal bleeding, systemic inflammation/sepsis, weight loss, and exacerbation of the underlying disease process. Other presentations of internal GIF may include gallstone ileus in cases of cholecystoduodenal fistulae and pneumaturia/recurrent urinary tract infections in cases of enterovesical fistulae.
| Diagnosis of Gastrointestinal Fistulae|| |
When approaching GIF, the diagnostic goal is to establish precise anatomic definition and classification of the fistula. Clinical evaluation of any GIF should begin with a detailed examination of the patient's medical and surgical history, followed by an assessment of the patient's general condition, serum electrolyte levels, and nutritional status (including albumin and prealbumin levels).
Further diagnostic evaluation may include upper and lower endoscopy, upper and lower intestinal radiography with soluble contrast medium, ultrasonography, computed tomography, and/or magnetic resonance imaging scanning (when appropriate). Fistulography with fluoroscopy may be very useful and is usually readily available. When approaching extraintestinal fistulae, additional imaging/diagnostic techniques may be needed. In cases of suspected biliary fistula, a magnetic resonance cholangiopancreatography and/or endoscopic retrograde cholangiopancreatography may be needed. In cases of suspected bladder fistula, cystoscopy, pyelography, and cystography may be helpful.,,,,
| Gastrointestinal Fistulae: Management Principles|| |
In general, the management of GIF can be divided into specific phases. These three distinct phases are: (a) fistula recognition and patient stabilization; (b) fistula investigation and assessment; and (c) definitive treatment of the fistula.,,,
Once the fistula is recognized, the patient has to be stabilized. This includes fluid resuscitation, correction of serum electrolytes and normalization of acid-base imbalances. Control and reduction of fistula output also help in stabilizing electrolyte, fluid, and acid-base status. Control of sepsis is very important because fistula-related mortality is often associated with uncontrolled infection. Protection of skin and continued local wound care are extremely important. Finally, adequate nutritional support is crucial in patient stabilization.,,,
Following initial patient stabilization, the fistula investigation and assessment phase begins. Here, the fistulogram is the most important initial procedure [Figure 1]. Fistulography may involve traditional fluoroscopic and roentgenographic studies or may employ modern computed tomographic imaging. Regardless of the imaging modality, the information to be derived includes: (a) the source of the fistula; (b) the nature of the fistulous tract (length, course, relationships); (c) the absence or presence of bowel continuity; (d) the presence versus absence of distal obstruction; (e) the character of bowel adjacent to the fistula (presence of inflammation, stricture, etc.,); and (f) the presence or absence of an abscess cavity in communication with the fistula.,,,
|Figure 1: Example of a duodenal-biliary fistula. Image authored (2000) by Nevit Dilmen, reproduced under GNU Free Documentation License|
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Once the patient is clinically stabilized and the fistula adequately investigated and assessed, the management enters the treatment phase. There are different treatment options available, depending on the type and behavior of the GIF. In cases of clinically stable external high-output fistulae, somatostatin, and analogs can be used in conjunction with aggressive nutritional supplementation to facilitate spontaneous fistula closure. If there is no significant reduction in fistula output following initiation of somatostatin therapy, the somatostatin administration should be re-evaluated. In fact, clinical evidence suggests that while octreotide significantly decreases fistula output, its use does not speed spontaneous closure rates and may be associated with increased morbidity.,,,
Depending on the fistula location and the nature of drainage, definitive surgical intervention involves resection of the fistula and primary bowel anastomosis or diversion of the fecal stream proximal to the fistula. Premature attempts at operative fistula closure increase the risk of peritoneal contamination, intraoperative bleeding, and recurrent fistula formation. Therefore, surgical repair should not be undertaken for at least 3–12 months, depending on the complexity of the fistula and the patient's general condition. Definitive surgical treatment should not be undertaken if there is an undrained abscess or if the nutritional status is suboptimal (albumin <3.5 mg/L). Operations in the setting of inadequate nutritional status have been associated with high incidence of recurrent fistulae. Emergency surgery should be limited to controlling sepsis, draining abscesses, and insertion of feeding tubes.
| Gastrointestinal Fistulae Associated With Inflammatory Bowel Disease|| |
Fistulizing inflammatory bowel disease is characterized by transmural inflammation that leads to bowel adherence to adjacent structures, microperforation, and abscess formation, with subsequent fistula development. Approximately, 20%–40% of patients with Crohn's disease will develop a fistula. Of those, approximately half are internal fistulae and half are external.,,,
In the setting of inflammatory bowel disease, there were very few nonsurgical therapeutic options before the introduction of infliximab (anti-tumor necrosis factor monoclonal antibody). During the preinfliximab era, medical treatment of fistulae was largely limited to antibiotics, often administered over prolonged periods of time. Infliximab has significantly improved the management of fistulizing Crohn's disease. In the setting of infliximab therapy, external fistulae, and perianal fistulae tend to have a higher rate of closure when compared to other types of fistulae. However, because the fistulous tract may persist, recurrent fistulae, and pelvic abscesses may occur. Of note, before initiating infliximab therapy, the patient should undergo testing for the presence of tuberculosis (purified protein derivative skin test) because infliximab therapy has been associated with exacerbations of severe miliary tuberculosis.
| Gastrointestinal Fistulae: Special Considerations|| |
Maintenance of adequate nutritional status is crucial in the management of GIF, with the overall goals including positive nitrogen balance, provision of adequate trace mineral and vitamin replacement, and significant caloric (35–45 calories/kg/24 h) and protein (1.5–1.75 grams/kg/24 h) requirements. The trend in nutritional support for patients with GIF is away from total parenteral nutrition (TPN) whenever possible. It is well established that enteral nutrition is associated with (a) decreased nosocomial (especially fungal) infection rate; (b) improved immunologic, hormonal, and barrier functions of the gut; and (c) fistula closure rates similar to those achieved with TPN alone.
Refeeding of the distal bowel segment is still a controversial issue.,,, This concept relies on the fact that without the fistula, all of the biliary, pancreatic, and gastric secretions would be naturally propelled distally through the bowel. In the absence of distal obstruction, refeeding of all or part of the fistula output into the distal bowel, along with enteral feeding into the distal bowel, have been shown to be beneficial, especially in neonatal and pediatric patients with multiple enterostomies. In fact, it is thought that distal bowel refeeding may increase the absorptive function and integrity of the distal segment, help facilitate subsequent operative intervention, improve weight gain, and reduce the requirement for TPN.,,,
Application of negative pressure wound therapy (NPWT) offers new options for patients with fistulae in terms of the advanced wound and fistula management. Increasing evidence from various clinical studies supports the role of NPWT in reducing local chronic wound edema, enhancing granulation tissue formation, effectively containing the effluent, protecting the surrounding skin, and promoting healing. Specialized NPWT sponges and other protective equipment (nonadherent dressings, specialized stoma devices, etc.,) may be required to protect any exposed normal bowel and/or skin adjacent to the fistula site.
| Gastrointestinal Fistulae: Prognostic Considerations|| |
The outcome associated with GIF has changed significantly over the last two decades. This is largely due to the evolution of modern intensive care and the ability to provide adequate nutritional support. With conservative medical management that includes adequate enteral or parenteral nutrition, spontaneous closure of fistula occurs in about 25% of patients within 30–40 days. Nevertheless, the mortality (up to 40%) and morbidity rate associated with GIF remain uncomfortably high. Perhaps the most important factor correlating with higher mortality in this patient population is the volume of fistula output. In fact, it has to be emphasized that the closure rates and mortality quoted above are associated with the so-called “favorable” group of patients who have low-output fistulae, and have no underlying systemic disease or fistula-associated abscess formation.,,,,,
| Conclusions|| |
Despite significant advances over the last two decades, GIF continues to present a significant challenge to surgical practitioners. Patients with GIF have the best chance for recovery if an orderly and systematic approach to their care is undertaken. This approach consists of patient stabilization, fistula investigation and assessment, and definitive treatment. While some fistulae close spontaneously with medical management alone, a significant proportion of GIF requires surgical intervention. Surgery is best performed following adequate patient stabilization and nutritional repletion, which often requires a delay of 3–12 months. Prognosis depends on the amount of fistula output, the control of associated infection, and maintenance of adequate nutritional status.
Justifications for re-publishing this scholarly content include: (a) The phasing out of the original publication after a formal merger of OPUS 12 Scientist with the International Journal of Academic Medicine and (b) Wider dissemination of the research outcome(s) and the associated scientific knowledge.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]