Chronic gastrointestinal bleeding of obscure origin: Role of small bowel enteroscopy

GASTROENTEROLOGY

ALIMENTARY

1988;94:1117-20

TRACT

Chronic Gastrointestinal Bleeding of Obscure Origin: Role of Small B&we1 EnteroscopyBLAIR S. LEWIS and JEROME

D. WAYE

Division of Gastroenterology, Mount Sinai Medical Center (CUNY), New York, New York

The source of blood loss remains undetermined in 5% of patients with chronic gastrointestinal bleeding. A new technique of small bowel enteroscopy with a prototypic sonde-type enteroscope 9 fi in length was used to examine 60 patients referred to the hospital with gastrointestinal bleeding of obscure origin. With an average procedure time of 6 h, the enteroscope migrated to the ileum or beyond in 77% of patients. Thirty-three percent (20 of 60 patients) had the source of blood loss identified within the small bowel at enteroscopy. Small bowel enteroscopy is a useful tool in patients with chronic gastrointestinal bleeding of obscure origin and can be considered when standard invasive and noninvasive modalities have failed to diagnose a site of bleeding.

pproximately 5% of patients with gastrointestinal bleeding will not have an identifiable source of blood loss despite exhaustive testing (l-3). These patients are categorized as cases of gastrointestinal bleeding of obscure origin (4). Of the known causes of obscure gastrointestinal bleeding, the most common is arteriovenous malformation (AVM), but other causes include hemangiomas, Meckel’s diverticulum, enteric duplication cysts, small bowel tumors, and Crohn’s disease (5,6). These patients may bleed either continuously or intermittently and vigorous bleeding may sporadically occur. Most patients present with anemia or positive fecal occult blood tests and have a history of multiple transfusions. This group of patients represents a difficult management problem as therapy depends on locating the site of blood loss (2). The difficulty in diagnosis is related in part to the many causes of gastrointestinal bleeding, some of which are located in the small bowel. The standard investigations for gastrointestinal pathology with radiography, endoscopy, and radioisotope scanning have not been diagnostic in these patients. A few patients with chronic gastroin-

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testinal bleeding may have the site located by invasive procedures including angiography, exploratory surgery, and intraoperative endoscopy. Each of the invasive procedures has associated disadvantages and all produce a low yield of diagnostic information. A nonsurgical, direct view of the small bowel mucosa has been demonstrated to be of use in identifying the source in patients with obscure gastrointestinal bleeding, but the task has been difficult and time consuming, and costs of development have been judged as prohibitive (7,8). Recent advances in the instrumentation and techniques of enteroscopy now permit such examination to be performed on a clinical basis (9-12). This report is on the use of a prototypic small bowel enteroscope to investigate patients with gastrointestinal bleeding of obscure origin. The sonde-type small bowel enteroscope involves the passage of a long, flexible fiberoptic endoscope (much like a Cantor tube) into the small bowel, relying on peristalsis to move it through the intestine. Direct visual inspection of the small intestinal mucosa is accomplished upon withdrawal of the instrument. Materials

and Methods

The sonde-type small intestinal fiberscope (SSIF VII) is a prototypic instrument, 5 mm in diameter and 2790 mm long, developed by Olympus Corp. (Cherry Hill, N.J.). The instrument is forward-viewing with a 90” angle of view. The SSIF VII is passed transnasally and migrates distally responding to peristaltic activity. The instrument has neither tip deflection controls nor interventional capability. There are two internal channels: one is for air insufflation of the intestinal lumen and the other inflates a balloon at the tip of the instrument, providing a bolus

Abbreviation used in this paper: AVM, arteriovenous malformation. 0 1988 by the American Gastroenterological Association 0018.5085/88/$3.50

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upon which peristalsis acts to pull the instrument through the small bowel. Experience gained over the past 5 yr with this instrument and the SSIF V, an earlier prototype, led to the

development of a new technique to increase patient compliance and shorten both total passage and examination time (13-15). The essential step in this method is the active placement of the small bowel enteroscope into the jejunum at the onset of intubation. After the SSIF VII is passed transnasally into the stomach, a sterilized pediatric colonoscope is passed orally for mucosal inspection and to carry the enteroscope “piggyback” through the pylorus into the small bowel. The balloon anchors the enteroscope in the small bowel as the colonoscope is removed. Metoclopramide is then given to enhance small bowel motility. To determine depth of insertion, an abdominal x-ray is taken before the withdrawal of the enteroscope. Mucosal visualization is achieved while removing the instrument with mild traction. Between October 1985 and August 1987, the SSIF VII enteroscope was used in 60 patients referred for small bowel enteroscopy to investigate chronic gastrointestinal bleeding of obscure origin. Forty-nine patients were female, 11 were male. The mean age was 69 yr (range 28-88 yr). Most patients had a long history of bleeding, the mean being 3 yr (range 1 mo-12 yr). Fifty-four patients had received transfusions: 28 received transfusions during one or two hospitalizations, whereas 26 required repeated transfusions. All transfusion patients had received >2 U of packed red blood cells in the month before examination. Before small bowel enteroscopy was performed, extensive investigations with upper gastrointestinal and small bowel series, barium enema, upper endoscopy, and colonoscopy were performed at the facility from which patients were referred. Forty-three patients had multiple endoscopic examinations. Fifty-one patients had radioisotope scans, 23 patients underwent angiography, 11 patients had exploratory surgery, 4 had enteroclysis, and 5 had stepwise aspiration of intestinal contents via a Cantor tube. All tests failed to find a source of blood loss.

Results Small bowel enteroscopy was performed in 60 patients, 48 of whom were examined on an ambulatory basis. The SSIF VII did not pass in 3 patients: 1 patient with a large ventral hernia had a retroperitoneal cyst that precluded passage, a second patient pulled the instrument out before examination, and a third patient with sickle cell disease was chronically receiving narcotics, which delayed intestinal transit. The tip of the SSIF VII migrated to the colon in 5 patients, the distal ileum in 31, the proximal ileum in 10, and the distal jejunum in 11 (Figure 1). The average procedure time was 6 h (range 3-8 h). Because of loops in the small bowel and the inability to advance the instrument during withdrawal, mucosal inspection of the small bowel segments transversed by the enteroscope was estimated to

Figure

1 X-ray appearance of the small bowel enteroscope. This film was taken 3.5 h after insertion and shows the distal tip of the instrument in the ileum.

include 50%-70%. Deep palpation of the anterior abdominal wall as the instrument was being withdrawn resulted in visualization of greater portions of mucosa. All patients in whom the enteroscope passed tolerated the procedure well. Epistaxis in 4 patients was the only complication and required local tamponade in 2 patients. A possible site of blood loss was identified in 20 of the 60 patients who had small bowel enteroscopy. Arteriovenous malformations were visualized in 16 of these 20 patients, ulcers in 3 patients, and fresh blood without a lesion in 1 patient. Seven patients, whose AVMs were limited to the proximal jejunum, subsequently received endoscopic fulguration of these lesions using a disinfected, orally passed colonoscope. Three patients with distal small intestinal AVMs isolated to discrete areas were subsequently referred for laparotomy with resection guided by intraoperative endoscopy. There was excellent correlation between both the number and location of lesions seen during small bowel enteroscopy and intraoperative endoscopy. Pathologic examination confirmed the presence of AVMs in these cases. Six other patients with diffuse small bowel AVMs were considered nonresectable because of the extent of the lesions. Previously undiagnosed ulcerations of the small bowel were discovered at enteroscopy in 3 patients, one of whom had ulcerative jejunitis, another had ulcerations secondary to potassium chloride, and a third had a leiomyosarcoma. The patient in whom fresh blood was seen in a discrete area of the small intestine, but without a

May 1988

visualized mucosal lesion, died of a cerebrovascular accident while awaiting exploratory surgery. Twenty-two of the remaining 37 patients who had a normal small bowel at enteroscopy were found to have possible sources of blood loss within the esophagus, stomach, or duodenal bulb during “push enteroscopy” despite previous negative upper endoscopies performed before referral. Follow-up of the 15 patients who had successful small bowel enteroscopy without an identifiable cause for bleeding revealed that one of them had subsequent exploratory laparotomy with intraoperative endoscopy that failed to find a source of blood loss, and another who subsequently died of cardiac causes had colonic AVMs identified at autopsy without small bowel lesions.

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diameter necessitating oral passage. Oral passage was met with a great deal of patient dissatisfaction because of salivation, nausea, and oropharyngeal discomfort. Tip deflection was added to the enteroscope in the fifth prototype but made the instrument too stiff to transverse the multiple loops and bends of the small bowel. The SSIF VII has a greater field of vision than earlier prototypes and its transnasal passage is accepted by more patients. Prolonged intubation time for the SSIF VII has previously been a problem, with a recent report in 7 patients of passive passage through the pylorus averaging 14.7 h insertion time (12). Neither the ropeway nor sonde method has heretofore gained clinical acceptance (7,8). The new technique for small bowel enteroscopy described herein allows intubation in an average of 6 h, reaching ileum or beyond in 77% of patients. The procedure can be performed on an Discussion ambulatory basis. The yield of small bowel enterosChronic gastrointestinal blood loss of obscure copy for finding a bleeding site was 33% of 60 origin presents a vexing medical problem where the patients with gastrointestinal bleeding of obscure inability to locate the site of blood loss is due to origin. Long intubation time is still one of the limimultiple factors. The slow rate of bleeding may limit tations of small bowel enteroscopy, as are a lack of the diagnostic capabilities of angiography (1,16)or intervention capability and inability of total mucosal exploratory laparotomy using either transilluminainspection. Visualization of the intestinal lumen by tion or multiple enterotomies (1,4), and intermittent small bowel enteroscopy is estimated to be only bleeding may circumvent the sensitivity of radioiso50%-70% complete even when intubation of the tope scanning. We have confirmed that AVMs are the entire small bowel is achieved. This limitation may most common cause of gastrointestinal bleeding of result in missing isolated nonactively bleeding leobscure origin (5),accounting for 80% (16 of 20 sions and is related to the many loops of the intescases) of our findings in 60 patients referred for small tine, the lack of tip deflection, and the inability to bowel enteroscopy. The accuracy of any diagnostic re-advance the instrument once withdrawal has beexamination for this problem is limited by the tengun. dency for AVMs to be evanescent, and any visualSmall bowel enteroscopy is a tedious and timeized lesion may not in fact be the true bleeding consuming procedure, rendering it unacceptable as source (1,16).Autopsy may not disclose the source an initial test for gastrointestinal bleeding. The of blood loss in 59&-7% of this patient group (16). proper role for this procedure is to follow nondiagNonsurgical total small bowel enteroscopy has nostic routine barium radiography, endoscopy, and been successfully accomplished by two different radionuclide studies in the patient with chronic methods. One method uses an instrument pushed continued or recurrent bleeding who requires transover a previously passed guide-string (11,17,18), fusion. Because of the safety of this procedure, we whereas the sonde method relies on peristalsis to advocate its use, if available, before angiography and move a long endoscope through the intestine (9-15). certainly before exploratory laparotomy. Both methods have been tedious, uncomfortable, The findings of small bowel enteroscopy should be and time consuming for patients as well as physiused as a guide to subsequent therapy. If no lesions cians, with procedure times ranging from overnight are seen, and the entire small bowel has been visuto several days. The guide-string for the “rope-way” alized, subsequent exploratory laparotomy will probably be unrewarding as well. When bleeding method may take several days to pass from mouth to rectum and general anesthesia is occasionally necessites are identified, a variety of options exist. Surgery sary to relieve the pain induced, as the string is may be ruled out when lesions are located diffusely throughout the small intestine as was advised in 6 of stretched taut before the endoscope is pushed over the patients found to have small bowel AVMs during it. Several sonde enteroscope prototypes have been small bowel enteroscopy. When the bleeding sites developed to achieve an instrument lightweight and are close to the ligament of Treitz, an attempt at flexible enough to pass into the distal small bowel fulguration with an orally passed long endoscope and improve patient comfort (11).Prototypes SSIF may be definitive, as it was in 7 of our patients. The I-IV had a narrower field of vision (65")and a larger

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finding of an isolated lesion or groups of lesions in specific segments of the small bowel calls for exploratory laparotomy with intraoperative endoscopy, as performed in 4 of our patients (3 patients with AVMs and 1 patient with a leiomyosarcoma). Because the small bowel enteroscope has no capability for marking the site of bleeding, the areas must be endoscopically reidentified during laparotomy so that the surgeon can precisely determine their location and be guided in the extent of surgical resection. With these different possible therapeutic approaches, small bowel enteroscopy may in the future prove to be a prerequisite for exploratory surgery in patients with obscure bleeding. We conclude that small bowel enteroscopy is an additional and useful test in the evaluation of the patient with gastrointestinal bleeding of obscure origin. It is safe and can be performed on an ambulatory basis. Ileum can be reached in 77% of patients in an average of 6 h. In one-third of patients investigated for bleeding, a probable cause was found. Small bowel enteroscopy should be considered when standard diagnostic modalities have failed to diagnose the site of bleeding and when an alternative to surgical exploration is desired.

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Received June 1, 1987. Accepted December 14, 1987. Address requests for reprints to: Blair S. Lewis, M.D., 650 Park Avenue, New York, New York 10021.