Published online before print May 30, 2002, 10.1148/radiol.2241011185
(Radiology 2002;224:9-23.)
© RSNA, 2002
Acquired Gastrointestinal Fistulas: Classification, Etiologies, and Imaging Evaluation1
Perry J. Pickhardt, MD,
Sanjeev Bhalla, MD and
Dennis M. Balfe, MD
1 From the Department of Radiology, National Naval Medical Center, 8901 Wisconsin Ave, Bethesda, MD 20889-5600 (P.J.P.); Department of Radiology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Md (P.J.P.); and the Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (S.B., D.M.B.). Received July 12, 2001; revision requested August 20; revision received September 14; accepted October 16. Address correspondence to P.J.P. (e-mail: pjpik@hotmail.com).
 |
ABSTRACT
|
|---|
Fistulas are abnormal communications between two epithelial-lined surfaces. Gastrointestinal fistulas encompass all such connections that involve the alimentary tract, and they can be congenital or acquired in nature. This review focuses on acquired gastrointestinal fistulas. Development of an acquired gastrointestinal fistula can greatly affect patient outcome, yet the clinical manifestations are often protean in nature and the etiology, elusive. Imaging plays an important role in the detection and management of acquired gastrointestinal fistulas. The more routine use of cross-sectional imaging (especially computed tomography and magnetic resonance imaging) has altered the standard sequence of radiologic evaluation for possible fistulas, but fluoroscopic studies remain a valuable complement, especially for confirming and defining the anomalous communications. In this review, a classification scheme for gastrointestinal fistulas is provided, major causes are discussed, and individual fistula types are elaborated with an emphasis on contemporary imaging approaches.
© RSNA, 2002
Index terms: Barium enema examination, 70.1231, 70.1232, 80.123 • Fistula, gastrointestinal tract, 70.245, 70.25, 70.26, 70.27 • Fistula, genitourinary system, 80.23, 80.245 • Gastrointestinal tract, CT, 70.12111, 70.12112 • Gastrointestinal tract, radiography, 70.123 • Genitourinary system, CT, 80.12111, 80.12112 • Review
|
INTRODUCTION
|
|---|
Gastrointestinal (GI) fistulas represent abnormal ductlike communications between the gut and another epithelial-lined surface, such as another organ system, the skin surface, or elsewhere along the GI tract itself. A GI sinus tract, in comparison, is a similar ductlike passage that communicates with the gut at one end but ends blindly at the other. The development of a GI fistula can markedly increase patient morbidity and mortality, rendering detection of the fistula critical. Imaging often plays a pivotal role in the diagnosis and management of GI fistula, with fluoroscopic contrast agent–enhanced studies serving as the traditional standard bearer. The emergence of cross-sectional imaging techniques, however, has modified the radiologic approach to GI fistulas. Instead of replacing fluoroscopic contrast-enhanced studies, cross-sectional methods complement their conventional counterparts in the evaluation of GI fistulas.
In this review, we will provide an organ-system approach to classifying GI fistulas. A brief discussion of the major causes of acquired GI fistulas will follow. Last, a systematic review of GI fistulas according to our classification scheme will be provided, with an emphasis on contemporary imaging evaluation. The relative contribution and effectiveness of the various imaging modalities will be discussed for individual fistula types, because many unique features and challenges exist. The salient clinical features of specific GI fistulas, including management, will also be covered.
|
CLASSIFICATION OF GI FISTULAS
|
|---|
GI fistulas are generally named according to their participating anatomic components, and virtually every imaginable combination has been reported in the medical literature. Rather than recite all possible permutations, a more general approach is presented here (Fig 1). Because the terminology can be somewhat variable, we have attempted to use fistula names that prevail in the literature, regardless of underlying etiology. To begin, it is useful to separate congenital and acquired causes, since their clinical settings and implications obviously differ greatly. Congenital GI fistulas are best understood by realizing their embryologic origin and include such entities as branchial, tracheoesophageal, and omphalomesenteric fistulas. Congenital fistulas, however, are beyond the scope of this review and will not be considered further.
Acquired GI fistulas can be categorized as external or cutaneous if they communicate with the skin surface or internal if they connect to another internal organ system or space, including elsewhere along the GI tract itself. Internal GI fistulas can be further divided into two types: intestinal and extraintestinal. Intestinal fistulas refer to a gut-to-gut connection and may consist of any combination of stomach, small bowel, and colon. An enteroenteric fistula may refer to any intestinal fistula in the generic sense, although some may restrict this term to small-bowel fistulas only. Extraintestinal internal fistulas imply communication of the GI tract with another organ system such as the genitourinary system, biliary tree, or respiratory tract. Complex fistulas contain both internal and external components. For the purposes of this review, GI sinus tracts will not be covered in detail, nor will intentional surgically created fistulas.
|
CAUSES OF ACQUIRED GI FISTULAS
|
|---|
The underlying causes of acquired GI fistulas are diverse and can include virtually any process resulting in bowel perforation from within or bowel penetration from an extraintestinal process (Fig 2). The majority of external (cutaneous) fistulas represent a complication of recent abdominal surgery (1). The leading causes of internal fistulas in the industrialized world are Crohn disease, diverticulitis, malignancy, or a complication of treatment of these entities. Not surprisingly, many cases are the result of multiple contributing factors; common examples include cancer patients who have undergone radiation therapy and patients with Crohn disease who have undergone prior bowel surgery. The specific location and type of fistula can often suggest certain causes, as will be seen when individual GI fistulas are covered more in depth. Some general features of the more common inflammatory causes will briefly discussed in the following paragraphs. Most of the remaining noninflammatory causes listed in Figure 2 will be covered in more detail in upcoming sections.
Fistula formation is a hallmark of Crohn disease, occurring in up to 20%–40% of patients described in surgical series (2). Sinus tracts and fistulas often involve the distal small bowel, and peritoneal abscess or phlegmon may be an associated finding (4). The clinical and radiologic manifestations vary widely because these internal fistulas can involve nearly any organ system, but ileocolic and enterovesical fistulas are the most common types (5). External fistulas are also common, especially in the perianal region (6). Fistula formation is considerably less common in ulcerative colitis, which, unlike Crohn disease, is not a transmural process (3). Rectovaginal fistula is the most frequent spontaneous GI fistula that develops in ulcerative colitis, followed by rectovesical fistula (7,8).
Diverticulitis is a common cause of colonic fistula formation, with the fistula most often communicating with the urinary bladder (9). Colovaginal fistulas are also relatively common in women with sigmoid colon diverticulitis, particularly after hysterectomy. Fistulas are seen in up to 20% of cases of surgically treated diverticular disease (9,10). Another relatively common finding in diverticulitis is a fistulous tract that parallels the colonic lumen, representing a localized form of colocolic fistula that has been termed "double tracking." Not surprisingly, fistula formation of the sigmoid colon predominates in diverticular disease, but other colonic segments are occasionally involved.
Other than Crohn disease and diverticulitis, other less common inflammatory causes of GI fistulas include atypical infections, cholecystitis, pancreatitis, and appendicitis (11,12). Among the various atypical infectious causes that have been reported are tuberculosis, histoplasmosis, actinomycosis, xanthogranulomatous pyelonephritis, amebiasis, echinococcosis, and lymphogranuloma venereum (13–19).
|
OVERVIEW OF IMAGING TECHNIQUES
|
|---|
Fluoroscopic contrast-enhanced studies and conventional radiographic studies have traditionally served as the cornerstone for imaging of spontaneous GI fistulas. However, technical advances and the increased availability of cross-sectional imaging modalities have challenged this paradigm. The result has been a more flexible hybrid approach that utilizes the strengths of the various complementary imaging modalities now available. The preferred imaging approach will vary according to fistula type and the specific clinical scenario. Furthermore, even individual fistula types often elude generalization and must be treated on a case-by-case basis. This underscores the importance of the radiologist in determining the most appropriate sequence of imaging studies for a given case. Because many fistulas may be detected incidentally on cross-sectional images obtained because of other indications, familiarity with the direct and indirect signs of fistulas is essential for this unsuspected diagnosis.
Despite this wide variability, some broad comments can be made with regard to the imaging approach. Once the selection is made between conventional and cross-sectional imaging as the initial study, other technical considerations follow. Contrast-enhanced fluoroscopic examinations often remain the initial study of choice and are generally superior to endoscopy in demonstrating the presence and extent of a GI fistula (4). Fistulography is adequate for diagnosis of most external (cutaneous) fistulas and is also useful for follow-up in these cases (20). On occasion, enteric contrast-enhanced studies, such as a small-bowel study or enema, will provide as much or more diagnostic information. For extraintestinal internal fistulas, one must decide between pursuing a primary bowel study and a study that directly opacifies the communicating organ system, such as urography, vaginography, cholangiography, and others. For intestinal (gut-to-gut) fistulas, enteric contrast-enhanced studies are superior and may be the only noninvasive method able to demonstrate these fistulas in some cases.
The choice of contrast agent is another important factor in the performance of conventional GI studies. A water-soluble iodinated contrast agent is generally used, at least initially, for abdominal fistulography and enteric studies when frank perforation is suspected or pneumoperitoneum is present. This is predicated on the potential for extravasated barium to incite an inflammatory reaction in the peritoneum, which can be followed by the formation of dense fibrous adhesions (21–23). The risk of clinically important chemical peritonitis, however, is minimal unless a relatively large amount of barium has leaked, especially with the newer barium preparations. A similar but more localized and less severe foreign body reaction can occur with retroperitoneal and extraperitoneal barium extravasation (24). Despite these caveats, it is important to remember that barium is more sensitive than aqueous contrast agents for demonstrating GI fistulas due to the tendency of the latter to dilute, resulting in lower radiographic opacity (1). This dilution of water-soluble contrast agents is especially limiting for small-bowel examination, and initial evaluation with barium should be strongly considered in patients without pneumoperitoneum, particularly for intestinal (gut-to-gut) fistulas (22). When a water-soluble contrast agent is used initially, a negative study should be followed by a barium study when the index of suspicion remains high.
For imaging of most internal GI fistulas with extraintestinal communication, an aqueous contrast agent is generally preferred. This is obviously the case when the extraenteric component is primarily opacified, as with urographic and cholangiographic contrast-enhanced studies. A water-soluble agent should also be used when there is a possibility of vascular communication, due to the potentially life-threatening complication of barium embolization (25). An exception to this rule of using an aqueous contrast agent for imaging of extraintestinal involvement involves GI fistulas communicating with the tracheobronchial tree, where barium is indicated and generally well tolerated. A water-soluble agent in this setting can lead to potentially lethal pulmonary edema due to their relatively high osmolarity, although the risk is lower with nonionic agents (26,27). Furthermore, unless a large esophageal leak is suspected, barium remains the contrast agent of choice for esophagography, since the risk of clinically important mediastinitis or granuloma formation appears to be negligible with small amounts of barium extravasation (27).
Cross-sectional imaging, particularly computed tomography (CT), has further strengthened the radiologist’s armamentarium for evaluating GI fistulas. CT effectively complements conventional radiography with its ability to demonstrate extraluminal disease, including associated abscesses, tumor, or other coexisting processes. Although CT may be less sensitive for direct detection of some GI fistulas, there are instances where it may be more sensitive than conventional studies, such as with enterovesical fistulas (4,28,29).
Regardless of whether the fistula is directly detected at CT, CT often yields more valuable information overall with respect to patient care. Furthermore, it is important to at least consider the need for obtaining a CT scan prior to performing a conventional barium examination, because residual barium can produce troubling artifacts on CT. Technical advances such as multi–detector row CT allow for effective multiplanar reformations and volume-rendering techniques to directly display fistulas not oriented in the traditional transverse plane. Often, CT directly or indirectly demonstrates the presence of a GI fistula, elucidates the underlying cause, and obviates further imaging. An additional advantage of CT is its utility in guiding percutaneous drainage of associated abscesses.
Magnetic resonance (MR) imaging holds similar promise for the evaluation of certain forms of possible GI fistulas, but the application of MR imaging has been most visible in the evaluation of enterocutaneous fistulas, especially in the perianal region (30–32). Faster imaging sequences and the use of oral contrast agents may further expand the role of MR imaging in the future, but CT remains the primary cross-sectional modality for fistula evaluation because it is rapid, generally available, and less costly than MR imaging. Sonography plays a much more limited role in the evaluation of most GI fistulas and typically requires a corroborative study for confirmation (28,33).
The remainder of this review will focus on the specific forms of GI fistulas.
|
INTERNAL GI FISTULAS
|
|---|
Internal GI fistulas include both intestinal and extraintestinal types. Although some of these fistulas may be suspected on clinical grounds, their presence is often first discovered at imaging, sometimes quite unexpectedly. Complex GI fistulas (Fig 1) may consist of virtually any combination of internal and external communication, but for the purpose of this review each component will be considered separately.
Intestinal Fistulas
Intestinal (gut-to-gut) fistulas may involve any or all combinations of the small bowel, colon, and stomach. The clinical manifestation of this subset may be subtle, since only the alimentary tract is involved. Diarrhea, with or without abdominal pain, is the most common symptom overall (9). There are several factors that influence which segments of bowel are involved in the fistulous communication. In cases where a primary bowel abnormality is the underlying cause, the segment of diseased bowel will obviously be at highest risk. Proximity to the pathologic process, be it intestinal or extraintestinal, is also important. Finally, a preexisting or preferred pathway between certain portions of the gut, as with a connecting ligament or mesentery, explains the predisposition for some intestinal fistulas to form (see discussion of gastrocolic fistula later).
Enteroenteric and enterocolic fistulas are common complications of Crohn disease, where fistulas are often multiple and favor the ileocecal region (Fig 3). Enterocolic fistulas in Crohn disease are usually due to primary small-bowel disease, whereas the opposite is true for colonic diverticulitis. Overall, coloenteric fistulas constitute fewer than 10% of fistulas complicating diverticulitis (9). A more common form of intestinal fistula from diverticulitis is the so-called double-tracking colocolic fistula (Fig 4). This intraloop form of intestinal fistula results from localized perforation and paracolic extension that parallels the bowel lumen. A similar appearance can be seen with Crohn disease and perforated adenocarcinoma of the colon. Intestinal fistulas can also be seen in cases of other abdominal malignancies, radiation therapy, surgery, and foreign bodies (Fig 5) (34–36).
View larger version (164K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3a. Enteroenteric and enterocolic fistulas. (a) Frontal radiograph from barium-enhanced small-bowel study in a 25-year-old man with Crohn disease shows multiple fistulous tracts extending from the terminal ileum (arrowheads), converging to a small mesenteric cavity (*), and communicating with the cecum and more proximal ileum (arrows). (b) Transverse contrast-enhanced CT scan in a 24-year-old man with Crohn disease shows irregular bowel wall thickening, mesenteric infiltration, and contrast agent-filled extraluminal tracts (arrows) centered in the ileocecal region. This complex enterocolic fistula involved distal ileum, cecum, ascending colon, and sigmoid colon.
|
|
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3b. Enteroenteric and enterocolic fistulas. (a) Frontal radiograph from barium-enhanced small-bowel study in a 25-year-old man with Crohn disease shows multiple fistulous tracts extending from the terminal ileum (arrowheads), converging to a small mesenteric cavity (*), and communicating with the cecum and more proximal ileum (arrows). (b) Transverse contrast-enhanced CT scan in a 24-year-old man with Crohn disease shows irregular bowel wall thickening, mesenteric infiltration, and contrast agent-filled extraluminal tracts (arrows) centered in the ileocecal region. This complex enterocolic fistula involved distal ileum, cecum, ascending colon, and sigmoid colon.
|
|
View larger version (166K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4a. Colocolic (double-tracking) fistula. (a) Frontal radiograph from air-contrast barium enema examination in a 50-year-old man 1 month after an episode of acute diverticulitis shows a long-segment narrowing (arrowheads) involving the sigmoid colon. At the distal aspect of the stricture, a second channel (arrow) parallels the colonic lumen, the so-called double-tracking sign. Note additional scattered diverticula. (b) Transverse contrast-enhanced CT scan obtained 1 month earlier than a during an acute episode shows pericolonic inflammatory changes and a small peridiverticular abscess (arrow). Adjacent large diverticulum (arrowhead) may represent the point of eventual fistula reentry. Perforation with a localized fistula was confirmed at surgery and pathologic examination.
|
|
View larger version (177K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4b. Colocolic (double-tracking) fistula. (a) Frontal radiograph from air-contrast barium enema examination in a 50-year-old man 1 month after an episode of acute diverticulitis shows a long-segment narrowing (arrowheads) involving the sigmoid colon. At the distal aspect of the stricture, a second channel (arrow) parallels the colonic lumen, the so-called double-tracking sign. Note additional scattered diverticula. (b) Transverse contrast-enhanced CT scan obtained 1 month earlier than a during an acute episode shows pericolonic inflammatory changes and a small peridiverticular abscess (arrow). Adjacent large diverticulum (arrowhead) may represent the point of eventual fistula reentry. Perforation with a localized fistula was confirmed at surgery and pathologic examination.
|
|
View larger version (167K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5. Enterocolic fistula. Spot radiograph obtained during air insufflation for air-contrast barium enema examination in a 58-year-old man shows unsuspected communication between sigmoid colon and small bowel (arrowheads). The patient had undergone successful surgical removal of an infected abdominal aortic graft 6 months earlier. Note also faint contrast agent (arrow) extending along aortic region.
|
|
In general, contrast-enhanced fluoroscopic GI studies remain the most effective means for help in diagnosing intestinal fistulas. When the colon is involved, a contrast agent enema examination is the study of choice and will demonstrate the fistulous communication more often than an upper GI examination, due to the increased intraluminal pressure in the latter (Fig 5) (20). A small-bowel follow-through examination may be the only noninvasive means for detecting some enteroenteric fistulas, but a successful examination requires vigilance and a high index of suspicion by the radiologist. Enteroclysis may be more sensitive for the detection of some enteroenteric fistulas, but it is a more invasive procedure that requires small-bowel intubation. These fistulas tend to be subtle on cross-sectional images but may be detected as a serendipitous finding on occasion (Fig 6b) (37). Although treatment principles are similar in many respects to the enterocutaneous fistulas discussed later in this article, intestinal fistulas rarely close spontaneously, and surgical correction is generally required (38).
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6a. Gastrocolic fistulas. (a) Frontal radiograph from solid-column barium enema examination in a 57-year-old man shows fistulous communication between the transverse colon and stomach via a large benign gastric ulcer (*) extending into the gastrocolic ligament. Note smooth folds radiating from the ulcer crater and absence of a gastric or colonic mass. (b) Contiguous transverse contrast-enhanced CT scans in a 59-year-old woman with abdominal pain and vomiting show pericolonic inflammatory changes surrounding a large transverse colonic diverticulum (arrows) in the gastrocolic region. The process blends imperceptibly with thickened gastric antrum (arrowheads). (c) Image from contrast-enhanced enema examination in the same patient as in b shows gastrocolic fistula (arrowhead), which proved to be secondary to diverticulitis at surgery and pathologic examination.
|
|
View larger version (157K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6b. Gastrocolic fistulas. (a) Frontal radiograph from solid-column barium enema examination in a 57-year-old man shows fistulous communication between the transverse colon and stomach via a large benign gastric ulcer (*) extending into the gastrocolic ligament. Note smooth folds radiating from the ulcer crater and absence of a gastric or colonic mass. (b) Contiguous transverse contrast-enhanced CT scans in a 59-year-old woman with abdominal pain and vomiting show pericolonic inflammatory changes surrounding a large transverse colonic diverticulum (arrows) in the gastrocolic region. The process blends imperceptibly with thickened gastric antrum (arrowheads). (c) Image from contrast-enhanced enema examination in the same patient as in b shows gastrocolic fistula (arrowhead), which proved to be secondary to diverticulitis at surgery and pathologic examination.
|
|
View larger version (160K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6c. Gastrocolic fistulas. (a) Frontal radiograph from solid-column barium enema examination in a 57-year-old man shows fistulous communication between the transverse colon and stomach via a large benign gastric ulcer (*) extending into the gastrocolic ligament. Note smooth folds radiating from the ulcer crater and absence of a gastric or colonic mass. (b) Contiguous transverse contrast-enhanced CT scans in a 59-year-old woman with abdominal pain and vomiting show pericolonic inflammatory changes surrounding a large transverse colonic diverticulum (arrows) in the gastrocolic region. The process blends imperceptibly with thickened gastric antrum (arrowheads). (c) Image from contrast-enhanced enema examination in the same patient as in b shows gastrocolic fistula (arrowhead), which proved to be secondary to diverticulitis at surgery and pathologic examination.
|
|
Discussion of all types of intestinal fistulas is not feasible in this review but one specific type, the gastrocolic fistula, is worthy of further attention. The gastrocolic ligament allows for bidirectional spread of pathologic processes between the greater curve of the stomach and the transverse colon. Although carcinomas of the stomach and colon were once thought to be the most common cause of gastrocolic fistula, it now appears that most cases are due to penetrating benign gastric ulcers, particularly in the setting of nonsteroidal antiinflammatory drug, or NSAID, use (39). Not surprisingly, various other neoplastic and inflammatory causes have also been reported in the literature (37). Unfortunately, the more suggestive clinical symptoms of feculent vomiting and undigested food in the stool are less common than nonspecific findings such as abdominal pain. Contrast-enhanced enema examination remains the most reliable means for detection, but its superiority over a contrast-enhanced upper GI study has likely been overemphasized (Fig 6a) (39). Although barium studies will more often demonstrate the fistula directly and can usually suggest a benign or malignant cause, CT is likely more accurate for evaluation of the gastrocolic region for the presence of a bulky mass or alternate cause (Fig 6b). Most gastrocolic fistulas are treated with en bloc resection. However, gastrocolic fistulas due to benign gastric ulcer disease are the exception, because they may spontaneously resolve after NSAIDs are withdrawn (39).
Extraintestinal Fistulas
The extraintestinal fistulas constitute a diverse and intriguing collection of acquired GI fistulas since they can connect the gut with virtually any other organ system. Extraintestinal fistulas involving the genitourinary, biliary, vascular, and respiratory systems are considered below.
Genitourinary tract.—Communication between the GI and genitourinary tracts represents a major subset of extraintestinal internal fistulas. The bladder and vagina are most often affected, but involvement of the upper collecting system, urethra, or uterus is occasionally seen. Available diagnostic modalities for evaluating these lesions include urographic studies, contrast-enhanced GI studies, cross-sectional imaging, and endoscopic procedures. The most appropriate initial study varies according to fistula type, and the management approach continues to evolve. Both CT and MR imaging have proved to be useful for noninvasive evaluation of pelvic fistulas (30,31).
The term enterovesical fistula is often generally applied for bladder communication with the colon, small bowel, rectum, or appendix (28,40). Sigmoid diverticulitis is the single most common cause of enterovesical (specifically, colovesical) fistula (9). Furthermore, fistulas to the urinary bladder account for over half of all internal fistulas encountered in diverticular disease (Fig 7). Crohn disease accounts for most small-bowel–to-bladder fistulas and may be present in up to 3%–4% of patients with this disease (Fig 8) (29). Pelvic malignancy, especially colorectal adenocarcinoma, is the other major cause of a GI fistula to the bladder, followed by radiation- and surgically induced fistulas. Approximately 20% of all enterovesical fistulas are rectovesical, and fewer than 5% are appendicovesical (Fig 9). Specific clinical symptoms (fecaluria and pneumaturia) are present in 40%–70% of patients, but nonspecific symptoms such as cystitis are invariably present (9,28,40–42).
View larger version (93K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7. Colovesical fistula. Transverse contrast-enhanced CT scans in a 56-year-old-man with pneumaturia and prior diverticulitis show air (arrowhead) in the bladder and the site of fistulous communication (arrow) between sigmoid colon and bladder. Note diverticulosis of the sigmoid colon.
|
|
View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8a. Enterovesical fistula. (a) Contiguous transverse CT scans obtained with intravenous and oral contrast agents in a 69-year-old woman with longstanding Crohn disease show a heterogeneous soft-tissue mass (M) associated with thickened ileal loops and adjacent bladder wall thickening (arrowhead). A small gas bubble (arrow) is present in the bladder lumen. (b) Fluoroscopic image shows contrast agent injection through a communicating enterocutaneous fistula and demonstrates the fistula (arrowhead) between the ileal segment and bladder. Small-bowel adenocarcinoma complicating Crohn disease was proved at surgery.
|
|
View larger version (146K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8b. Enterovesical fistula. (a) Contiguous transverse CT scans obtained with intravenous and oral contrast agents in a 69-year-old woman with longstanding Crohn disease show a heterogeneous soft-tissue mass (M) associated with thickened ileal loops and adjacent bladder wall thickening (arrowhead). A small gas bubble (arrow) is present in the bladder lumen. (b) Fluoroscopic image shows contrast agent injection through a communicating enterocutaneous fistula and demonstrates the fistula (arrowhead) between the ileal segment and bladder. Small-bowel adenocarcinoma complicating Crohn disease was proved at surgery.
|
|
View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9. Rectovesical fistula. Transverse contrast-enhanced CT scan in a 65-year-old-man with ulcerative colitis shows air in a fistulous tract (arrow) between inflamed rectum and bladder. Note also air (arrowheads) in bladder lumen.
|
|
Cystoscopy usually demonstrates inflammatory changes in the bladder but is nondiagnostic for fistula in the majority of cases (9,28,40,41). Likewise, conventional contrast-enhanced genitourinary and GI studies such as cystography and barium enema examination also yield false-negative results in most cases, as do sonography and GI endoscopy. CT, however, has demonstrated 90%–100% sensitivity for diagnosis (albeit with the use mainly of indirect signs and not direct demonstration of the fistula itself) and has been advocated for initial evaluation (28,41). Diagnostic CT findings that are present with most enterovesical fistulas include air in the bladder lumen (in the absence of recent catheterization) associated with focal bladder and/or bowel wall thickening (Figs 7–9) (28). Conventional studies are much less sensitive and specific for the detection of intravesical air. Although the fistula itself is often not directly demonstrated at CT (Fig 9), its location can generally be inferred from the secondary findings (Figs 7, 8). Furthermore, if an intravenous contrast agent is not used, the presence of an enteric contrast agent in the bladder on CT scans is diagnostic of a fistula. Alternatively, if an enteric contrast agent is not used, the presence of an intravenous contrast agent in the bowel is also diagnostic. Sensitivity can be increased further with direct rectal administration of a contrast agent or with a CT cystographic technique. Rescanning after active urination and defecation may also be useful when a suspected fistula is not demonstrated on the initial scan. CT can also provide important extraluminal information, such as the presence of an offending tumor (Fig 8). More recently, MR imaging has shown similar success in facilitating diagnosis (30). Treatment of enterovesical fistulas consists of single-stage surgical resection in the majority of cases (40,41).
GI fistulas to the kidney or upper urinary tract are much less common than bladder fistulas and are more often due to urologic disease rather than a primary GI process (17,43,44). The "retroperitonealized" portions of the colon and duodenum are most often involved. Communication of the colon with the pelvicaliceal system (renocolic fistula) or the ureter (ureterocolic fistula) typically occurs secondary to chronic suppurative renal infection in the setting of urolithiasis and/or obstruction, as seen with xanthogranulomatous pyelonephritis (17,43,45). Less common causes include tuberculosis, trauma, surgery, radiation therapy, Crohn disease, diverticulitis, and malignancy (Fig 10) (46–48). Although fecaluria and pneumaturia may be present, the clinical picture more often is nonspecific and related to chronic or recurrent urinary tract infection (44).
View larger version (163K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10a. Ureteroduodenal fistula. (a) Frontal radiograph obtained after retrograde contrast agent injection of right upper urinary collecting system in a 67-year-old man shows contrast agent within the duodenum (arrows) from an unsuspected fistula. Note wire (black arrowheads) and small amount of retained contrast agent (white arrowhead) in the collecting system. (b) Contrast-enhanced CT scan performed after a shows site of contact (white arrowhead) between duodenum and right ureter. The fistula likely resulted from injury during previous aortofemoral bypass surgery. Note vascular graft (black arrowhead) and right ureteral stent (arrow).
|
|
View larger version (169K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10b. Ureteroduodenal fistula. (a) Frontal radiograph obtained after retrograde contrast agent injection of right upper urinary collecting system in a 67-year-old man shows contrast agent within the duodenum (arrows) from an unsuspected fistula. Note wire (black arrowheads) and small amount of retained contrast agent (white arrowhead) in the collecting system. (b) Contrast-enhanced CT scan performed after a shows site of contact (white arrowhead) between duodenum and right ureter. The fistula likely resulted from injury during previous aortofemoral bypass surgery. Note vascular graft (black arrowhead) and right ureteral stent (arrow).
|
|
The combination of urography and CT is a useful approach in the evaluation for possible GI fistulas involving the kidneys and upper urinary tract (Fig 10) (43). Urographic studies are best for direct visualization of the fistula, and CT can be used to reliably assess the involved organs and surrounding tissues for the cause and extent of disease. It is important to note, however, that an excretory urogram will fail to opacify the fistula when the kidney is nonfunctioning, and a retrograde study may be nondiagnostic if an obstruction is present distal to the fistula. Direct antegrade pyelography can be useful in these situations (49). Surgical excision of the fistula, often with nephroureterectomy, is necessary in most cases.
The acquired rectovaginal fistula is the most common GI fistula involving the genital tract in women. Most cases are related to obstetric complications, inflammatory bowel disease, or some combination of gynecologic malignancy (particularly cervical cancer), surgery, and radiation therapy (7,50). Although the clinical symptoms, particularly the passage of feces through the vagina, usually indicate the presence of a fistula, its detection is often difficult on conventional GI studies unless a relatively large communication is present (Fig 11). Vaginography may demonstrate the fistula more clearly in subtle cases (51). More recently, CT and MR imaging have been shown to be useful for detection of rectovaginal and enterovaginal fistulas, whereas endorectal sonography appears to be relatively insensitive (30,33,52). An enteric contrast agent and/or air within the vagina can be demonstrated on CT scans in the majority of cases (52). Simple excision is often not adequate in these complex cases, and at least temporary colonic diversion is usually necessary. GI fistulas involving the uterine body and fallopian tubes are rare, compared with vaginal fistulas, and most often involve the left side of the colon (53). Most colouterine and colotubal (salpingocolic) fistulas result from diverticulitis, but a variety of other GI and genitourinary causes are possible, especially in younger women (9,53). Actinomycosis should be considered in the setting of an intrauterine device. A combination of hysterosalpingography and CT will provide a comprehensive preoperative assessment in most cases (Fig 12). Acquired rectourethral fistulas in males are also rare, with the majority of cases related to treatment for prostate cancer (Fig 13) (54).
View larger version (137K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11. Rectovaginal fistula. Lateral radiograph from air-contrast barium enema examination in a 38-year-old woman with ulcerative colitis shows air and contrast agent within the vagina (V). The site of communication (arrow) is visible inferiorly. The rectosigmoid region appears somewhat foreshortened and featureless.
|
|
View larger version (154K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 12. Salpingocolic (colotubal) fistula. Frontal pelvic radiograph from hysterosalpingogram in a 28-year-old woman with a history of pelvic inflammatory disease shows left hydrosalpinx and contrast agent filling a tubo-ovarian abscess cavity (A), with extension superiorly into the left side of the colon (arrowheads).
|
|
View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 13. Rectourethral fistula. Oblique radiograph from retrograde urethrogram in a 64-year-old man with a history of brachytherapy for prostate cancer shows contrast agent in the rectum (arrowheads). Contrast agent entered the rectum via a large communication with the prostatic urethra (arrow). As expected, contrast agent is also present in the anterior urethra and bladder (B). Note radiopaque brachytherapy implants in prostatic region.
|
|
Biliary tract.—Spontaneous internal biliary fistulas represent a complication of cholelithiasis or choledocholithiasis in over 90% of cases (11,55). Infrequent causes include peptic ulcer disease, malignancy, and prior surgery. In most series, cholecystoduodenal fistulas are the most common type, followed by cholecystocolic and choledochoduodenal fistulas (11). The clinical manifestation of enterobiliary fistulas is often nonspecific, and most cases are diagnosed on the basis of an unsuspected imaging finding (11). Distal small-bowel obstruction from an impacted ectopic gallstone, so-called gallstone ileus, is an unusual complication of chronic cholecystitis and affects only a minority of patients with cholecystoduodenal fistulas. Gallstones that result in intestinal obstruction typically exceed 2 cm in diameter (56). Obstruction at the level of the gastric outlet or duodenum represents a specific subset of gallstone ileus that is referred to as Bouveret syndrome (57). Surgery is indicated to relieve the obstruction in cases of gallstone ileus, and surgical correction is required for the biliary fistula, to prevent future complications.
Pneumobilia seen on imaging studies strongly suggests the presence of an internal biliary fistula in the absence of prior sphincterotomy, surgical bypass procedure, recent endoscopic retrograde cholangiopancreatography, or passed common duct stone. The Rigler triad of small-bowel obstruction, pneumobilia, and ectopic gallstone(s) is virtually pathognomonic for gallstone ileus but is present on conventional radiographs in only 30%–35% of cases (Fig 14a) (58). This triad of findings, however, is more readily apparent on CT scans (Fig 14b) (59). CT can also provide important information on the degree of bowel obstruction and suggest the likely site of fistula formation. Endoscopic retrograde cholangiopancreatography is a sensitive technique for direct demonstration of enterobiliary fistulas, especially those of the choledochoduodenal type. Conventional contrast-enhanced GI studies are somewhat less direct for direct demonstration but nonetheless are relatively noninvasive and may help detect an unsuspected communication with the biliary tree (Fig 15). Compared with CT, sonography is less accurate for detection of cholecystoenteric fistulas, but suggestive findings include an irregular contracted gallbladder, nonvisualization of the gallbladder, and pneumobilia (56).
View larger version (124K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 14a. Gallstone ileus from cholecystoduodenal fistula. (a) Supine radiograph in a 76-year-old woman shows bowel gas pattern suggestive of small-bowel obstruction, two ectopic calcified gallstones (arrowheads), and air in the biliary tree (arrows). These findings constitute the Rigler triad. (b) Transverse CT scans obtained without intravenous contrast agent in an 85-year-old woman show pneumobilia (arrowheads) and high-grade small-bowel obstruction from an ectopic gallstone (short arrow). Note also orthotopic gallstones (long arrow) with a similar appearance.
|
|
View larger version (129K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 14b. Gallstone ileus from cholecystoduodenal fistula. (a) Supine radiograph in a 76-year-old woman shows bowel gas pattern suggestive of small-bowel obstruction, two ectopic calcified gallstones (arrowheads), and air in the biliary tree (arrows). These findings constitute the Rigler triad. (b) Transverse CT scans obtained without intravenous contrast agent in an 85-year-old woman show pneumobilia (arrowheads) and high-grade small-bowel obstruction from an ectopic gallstone (short arrow). Note also orthotopic gallstones (long arrow) with a similar appearance.
|
|
View larger version (145K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 15. Cholecystocolic fistula. Spot radiograph from barium enema examination in an 81-year-old man with nonspecific abdominal complaints shows contrast agent within the gallbladder (*) from communication with the hepatic flexure. Air (arrowheads) is present within the biliary tree.
|
|
Vascular system.—Enteric fistulas involving the vascular system, whether arterial or venous, are potentially lethal and often require urgent correction. A high index of clinical suspicion is necessary, since a favorable outcome relies on prompt diagnosis. Imaging studies, particularly CT and contrast-enhanced GI studies, play an important role in the preoperative detection of these fistulas.
The aorta lies in proximity with the GI tract for much of its thoracic and abdominal course. Aortoenteric fistulas, therefore, can potentially involve the gut anywhere from the esophagus to the colon (60–62). The majority of cases occur in the presence of aortic aneurysm disease, either as a primary event or a secondary complication following surgical repair (60). Aortic fistulas involving the duodenum and esophagus warrant further consideration.
The duodenum participates in the majority of aortoenteric fistulas, owing to the proximity between its third portion and the underlying abdominal aorta. Primary aortoduodenal fistula is a rare life-threatening cause of gastrointestinal bleeding that results most commonly from an atherosclerotic aortic aneurysm (60,63). Unusual causes of a primary fistula include aortitis, radiation therapy, malignancy, and peptic ulcer disease (64,65). Most patients have upper or lower GI bleeding, but the classic triad of abdominal pain, GI bleeding, and pulsatile mass is present in fewer than 25% of cases (60,66). A "herald bleed" frequently precedes lethal exsanguination, and patient survival hinges on prompt diagnosis and emergent therapeutic laparotomy. Unfortunately, a correct preoperative diagnosis is determined in only a minority of cases, underscoring the importance of heightened clinical suspicion (60). Endoscopy is often the initial diagnostic study performed, but blood pooling may impair luminal visibility, and an alternate presumed source of bleeding is frequently identified, acting as a "red herring" (60). Conventional upper GI study, sonography, aortography, and tagged red blood cell scintigraphy all have marked limitations for diagnosis (67). CT, however, provides rapid and effective evaluation in hemodynamically stable patients suspected of having an aortoenteric fistula. CT findings such as perianeurysmal hematoma, pseudoaneurysm, contrast agent extravasation, periaortic or intraluminal gas, and focal duodenal wall thickening are highly suggestive of a fistula in the appropriate clinical setting (Fig 16a) (63,67,68).
View larger version (132K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 16a. Primary and secondary aortoduodenal fistulas. (a) Primary aortoduodenal fistula. Transverse nonenhanced CT scan in an 80-year-old woman with GI bleeding shows a calcified abdominal aortic aneurysm (A) with intraluminal gas (arrow). Massive high-attenuation retroperitoneal hemorrhage (H) surrounds the aorta. (b) Secondary aortoduodenal fistula. Contiguous transverse contrast-enhanced CT scans in a 71-year-old man with GI bleeding and history of aortic repair shows air (black arrow) in the lumen of the aortic graft and tethering (white arrow) of overlying duodenum associated with periaortic inflammatory changes.
|
|
View larger version (144K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 16b. Primary and secondary aortoduodenal fistulas. (a) Primary aortoduodenal fistula. Transverse nonenhanced CT scan in an 80-year-old woman with GI bleeding shows a calcified abdominal aortic aneurysm (A) with intraluminal gas (arrow). Massive high-attenuation retroperitoneal hemorrhage (H) surrounds the aorta. (b) Secondary aortoduodenal fistula. Contiguous transverse contrast-enhanced CT scans in a 71-year-old man with GI bleeding and history of aortic repair shows air (black arrow) in the lumen of the aortic graft and tethering (white arrow) of overlying duodenum associated with periaortic inflammatory changes.
|
|
Secondary aortoduodenal fistulas develop in fewer than 2% of aortic reconstructions but are still more common than primary fistulas (60,69). Clinical suspicion remains the linchpin for diagnosis of this condition, which must be considered in any patient with a prosthetic aortic graft and GI bleeding. As with primary fistulas, endoscopy and CT are the most useful diagnostic studies for initial evaluation in hemodynamically stable patients (69). However, although endoscopy may reveal mucosal defects or even graft eroding into the duodenum, it is diagnostic in fewer than 25% of cases (69). CT is a sensitive technique but its specificity for the diagnosis of fistulas is relatively low, especially in the early postoperative period when perigraft fluid and gas can be a normal finding. The CT appearance of secondary aortoenteric fistula overlaps substantially with that of graft infection, although the presence of extraintestinal air and associated duodenal abnormality is less common in the latter (Fig 16b) (70,71).
Aortoesophageal fistulas are rare; in the majority of cases, they are caused by localized rupture of a thoracic aortic aneurysm (72,73). Unusual reported causes include esophageal carcinoma, foreign body ingestion, syphilis, and infected aortic graft (73–76). The clinical manifestation is fairly characteristic and is described by the Chiari triad: midthoracic pain or dysphagia, a sentinel episode of hematemesis, and a symptom-free interval that gives way to massive upper GI bleeding (73,76). Diagnosis prior to exsanguination is obviously imperative for successful surgical repair. The chest radiograph will typically demonstrate the presence of an enlarged or tortuous thoracic aorta (72). In stable patients, the combination of CT and contrast-enhanced esophagography will usually be diagnostic. The esophagogram will usually demonstrate deviation of the esophagus due to the aneurysm, with or without ulceration (Fig 17b) (72). The CT findings are analogous to those seen with aortoduodenal fistulas (Fig 17a). Aortography was performed in the past but provides less information than does chest CT and only rarely will show the fistula directly (72,77).
View larger version (154K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 17a. Aortoesophageal fistula. (a) Transverse contrast-enhanced CT scan in a 52-year-old man with hematemesis and prior repair of thoracic aortic aneurysm with an endoluminal stent-graft shows air (arrowhead) in the aortic lumen adjacent to the stent-graft. Irregular air collection is also present in the expected region of the esophagus (arrow). (b) Oblique radiograph from contrast-enhanced esophagogram directly demonstrates aortoesophageal fistula (arrows), which was confirmed at surgery.
|
|
View larger version (173K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 17b. Aortoesophageal fistula. (a) Transverse contrast-enhanced CT scan in a 52-year-old man with hematemesis and prior repair of thoracic aortic aneurysm with an endoluminal stent-graft shows air (arrowhead) in the aortic lumen adjacent to the stent-graft. Irregular air collection is also present in the expected region of the esophagus (arrow). (b) Oblique radiograph from contrast-enhanced esophagogram directly demonstrates aortoesophageal fistula (arrows), which was confirmed at surgery.
|
|
Other than typical portomesenteric venous gas due to intestinal ischemia, pneumatosis, and other causes, true enterovenous and colovenous fistulas are rare but potentially lethal entities. The most common reported causes of duodenocaval fistula include migration of caval filters, right nephrectomy, peptic ulcer disease, and ingestion of a foreign body (78). Fistulas involving the mesenteric small bowel and the colon are usually secondary to Crohn disease and diverticulitis, respectively (79,80). These fistulas are often detected unexpectedly on barium studies by observing intravasation of the contrast agent (Fig 18). Substantial barium intravasation reportedly carries a high mortality rate (25,81). If the patient survives the acute episode, diffusely increased opacity of the spleen, greater than that of the liver, can be seen on both radiographs and CT scans due to reticuloendothelial uptake of the barium sulfate (81,82).
View larger version (157K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 18. Colovenous fistula. Postevacuation radiograph from barium enema examination shows contrast agent throughout the inferior mesenteric venous system (arrowheads). Colovenous fistula was due to diverticulitis. Note extensive sigmoid diverticulosis in this region. (Case courtesy of Charles A. Rohrmann, MD, Seattle, Wash.)
|
|
Respiratory tract.—Acquired esophagorespiratory fistulas account for the majority of intrathoracic GI fistulas and consist of communication with either the tracheobronchial tree or the pleura. Fistulas that communicate between the respiratory tract and the intraabdominal GI tract (ie, gastrobronchial, enterobronchial, and colobronchial fistulas) are rare but may result from a penetrating subphrenic abscess or a postsurgical complication (83,84). Likewise, gastropleural and colopleural fistulas are also rare and are usually associated with diaphragmatic herniation or prior pulmonary resection (85–87). Of these GI-respiratory fistulas, communication of the esophagus with the tracheobronchial tree and the pleura warrants further consideration.
Direct invasion by esophageal carcinoma is the most common cause of acquired tracheoesophageal and bronchoesophageal fistulas, seen in approximately 5% of cases (88,89). Fistulas are especially common following radiation therapy in these patients. Other causes of tracheo- and bronchoesophageal fistulas include primary lung and tracheal carcinoma, esophageal instrumentation, tracheal intubation, trauma, presence of foreign bodies, and granulomatous infection (89–91). Patients typically present with dysphagia and symptoms suggestive of aspiration. The barium esophagogram remains the study of choice, because it effectively differentiates fistula from aspiration (Fig 19a, 19b). The lateral projection will generally best define tracheoesophageal fistulas, whereas bronchoesophageal fistulas may require a slightly different obliquity. As previously mentioned, aqueous contrast agents should be avoided because of the risk of potentially lethal pulmonary edema. CT can be a useful adjunct in selected cases for evaluation of the underlying cause or assessment of tumor burden (Fig 19c). Treatment options for malignant fistulas include palliation with gastrostomy or jejunostomy, surgical bypass or correction, and endoprosthetic stent placement (88,92). For benign fistulas, the goal of treatment is generally to achieve definitive repair (89).
View larger version (109K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 19a. Tracheoesophageal and bronchoesophageal fistulas. (a) Lateral radiograph from barium esophagogram in a 61-year-old man with esophageal cancer shows contrast agent delineating tracheoesophageal communication (arrowhead). Note widening of tracheoesophageal stripe (*) and mass effect on the trachea from tumor. (b) Lateral radiograph from barium esophagogram in a 61-year-old man with recurrent pneumonia shows fistula (arrow) between esophagus and airway that was secondary to histoplasmosis. (c) Reformatted oblique transverse multi-detector row helical CT scan in a 47-year-old man with bronchogenic carcinoma shows irregular fistulous tract extending from the left bronchial tree (black arrowhead) to the esophagus (black arrow). Five standard transverse CT images (not shown) were needed to sequentially demonstrate the oblique course displayed on this single reformatted image. Note oral contrast agent (white arrow) in segmental bronchus and peripheral airspace consolidation (white arrowhead). The patient was treated with a covered esophageal stent.
|
|
View larger version (113K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 19b. Tracheoesophageal and bronchoesophageal fistulas. (a) Lateral radiograph from barium esophagogram in a 61-year-old man with esophageal cancer shows contrast agent delineating tracheoesophageal communication (arrowhead). Note widening of tracheoesophageal stripe (*) and mass effect on the trachea from tumor. (b) Lateral radiograph from barium esophagogram in a 61-year-old man with recurrent pneumonia shows fistula (arrow) between esophagus and airway that was secondary to histoplasmosis. (c) Reformatted oblique transverse multi-detector row helical CT scan in a 47-year-old man with bronchogenic carcinoma shows irregular fistulous tract extending from the left bronchial tree (black arrowhead) to the esophagus (black arrow). Five standard transverse CT images (not shown) were needed to sequentially demonstrate the oblique course displayed on this single reformatted image. Note oral contrast agent (white arrow) in segmental bronchus and peripheral airspace consolidation (white arrowhead). The patient was treated with a covered esophageal stent.
|
|
View larger version (140K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 19c. Tracheoesophageal and bronchoesophageal fistulas. (a) Lateral radiograph from barium esophagogram in a 61-year-old man with esophageal cancer shows contrast agent delineating tracheoesophageal communication (arrowhead). Note widening of tracheoesophageal stripe (*) and mass effect on the trachea from tumor. (b) Lateral radiograph from barium esophagogram in a 61-year-old man with recurrent pneumonia shows fistula (arrow) between esophagus and airway that was secondary to histoplasmosis. (c) Reformatted oblique transverse multi-detector row helical CT scan in a 47-year-old man with bronchogenic carcinoma shows irregular fistulous tract extending from the left bronchial tree (black arrowhead) to the esophagus (black arrow). Five standard transverse CT images (not shown) were needed to sequentially demonstrate the oblique course displayed on this single reformatted image. Note oral contrast agent (white arrow) in segmental bronchus and peripheral airspace consolidation (white arrowhead). The patient was treated with a covered esophageal stent.
|
|
Esophagopleural fistulas are perhaps best considered as a subset of esophageal perforation and usually result from prior surgery, endoscopic procedures, esophageal carcinoma, or radiation therapy (93). Clinical diagnosis is often difficult due to inconstant and nonspecific symptoms, especially in the absence of substantial mediastinal involvement (93). Chest radiography in patients with esophagopleural fistulas will demonstrate either pleural effusion or hydropneumothorax on the affected side in essentially all cases. Conventional esophagography is indicated for confirmation and localization of esophagopleural fistulas (Fig 20b). CT can also demonstrate pleural air, fluid, and/or contrast agent and can sometimes demonstrate the fistula itself (Fig 20a, 20c) (94).
TOP
ABSTRACT
INTRODUCTION
