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Keywords:

  • charcoal challenge test;
  • colouterine fistula;
  • contrast medium;
  • preoperative diagnosis;
  • sonohysterography

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report
  5. Discussion
  6. References

Colouterine fistulae secondary to sigmoid diverticulitis are unusual. Methods for diagnosis remain to be established. We report a case with a colouterine fistula in which sonohysterography detected the flow of ultrasound contrast medium between the uterine cavity and the sigmoid colon through the posterior uterine wall, thus confirming the diagnosis. The diagnosis was further substantiated by a charcoal challenge test. The patient underwent en bloc resection of the uterus, Fallopian tubes, ovaries and sigmoid colon, the organs involved with diverticulitis. This is the first report to describe a colouterine fistula successfully diagnosed by sonohysterography using ultrasound contrast medium. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report
  5. Discussion
  6. References

A colouterine fistula secondary to sigmoid diverticulitis is very rare, and only a limited number of cases with this condition have been reported in the literature1–4. The charcoal challenge test, the detection of orally administered charcoal flowing through the cervical os, was described as a non-invasive approach to diagnose this disease1. Similarly, abdominal computed tomography (CT) with oral contrast has been reported to be effective at detecting this type of fistula5. However, these methods are unable to demonstrate the fistula tract. Likewise, barium enema and colonoscopy detect colonic diverticuli, but frequently fail to detect the fistula tract. Here we report a case with a colouterine fistula in which sonohysterography with ultrasound contrast medium (Levovist®, Schering AG, Berlin, Germany) demonstrated the fistula tract.

Case Report

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report
  5. Discussion
  6. References

A 69-year-old woman, gravida 4 para 3, was referred to our hospital because of lower abdominal pain and persistent vaginal discharge for a month. The uterus was normal in size on palpation, and no abdominal or pelvic mass was present. The vagina was atrophic. The patient occasionally experienced vaginal bleeding with simultaneous black stool. Sonohysterography revealed a high-intensity, band-like echo in the uterine cavity (Figure 1), but magnetic resonance imaging demonstrated no abnormal findings in the uterus. Cultures of the vaginal discharge were positive for bowel flora including Klebsiella spp., Escherichia coli, Bacillus and Pseudomonas aeruginosa. Endometrial curettage revealed acute endometritis with intensive infiltration of neutrophils into the endometrial stroma. The patient was afebrile; her C-reactive protein and white cell count were within the normal range. A barium enema and colonoscopy demonstrated diverticulosis of the entire colon but no fistula tract. We performed sonohysterography using 10 mL Levovist, which detected the abnormal flow of contrast medium between the posterior wall of the uterus and the sigmoid colon (Figure 2). Levovist is a white, liquid, ultrasound contrast agent with air microbubbles stabilized in galactose. It produces hyperechogenic scatter in addition to increased signal intensities in color or power Doppler mode. A small amount of white fluid was excreted from the anus about 30 min after the examination. To confirm a diagnosis of colouterine fistula we gave the patient oral activated charcoal. A tampon was inserted to prevent vaginal contamination from the rectum. The charcoal was seen in the vaginal discharge on the following day.

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Figure 1. Sonohysterography demonstrates a high-intensity echo (arrow) in the uterine cavity.

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Figure 2. Sonohysterography detects the abnormal flow (arrow) of Levovist®, the contrast medium, between the posterior wall of the uterus and the sigmoid colon.

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At laparotomy, a portion of the sigmoid colon was adherent to the uterine fundus. The fistula was resected en bloc through total hysterectomy with bilateral salpingo-oophorectomy and partial sigmoidectomy followed by end-to-end anastomosis. Pathological examination revealed extensive diverticulosis and a fistula tract connecting a diverticular abscess and the uterine cavity (Figure 3).

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Figure 3. The resected organs show the existence of a fistula connecting a diverticular abscess and the uterine cavity.

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Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report
  5. Discussion
  6. References

This is the first report of sonohysterography with ultrasound contrast medium demonstrating a fistula tract between the sigmoid colon and the uterus. Although there have been reports on a colouterine fistula tract detected by hysterosalpingography6, 7, sonohysterography has some advantages over radiographic fistulography. First, ultrasonography visualized not only the fistula tract but also the uterine wall and the sigmoid colon. Second, ultrasound examination prevented X-ray exposure and possible allergic response to a radio-opaque medium.

A charcoal challenge test, which detects the outflow of ingested charcoal from the cervical os, is informative in diagnosing an enterouterine fistula. This test is simple and safe, and is acceptable as the initial examination when an enterouterine fistula is suspected. Abdominal CT with oral contrast would demonstrate the contrast in the uterine cavity, however it is expensive and requires X-ray exposure. A high-intensity echo due to a gas bubble in the uterine cavity on sonohysterography has been proposed by Kiyokawa to be a sign of the presence of an enterouterine fistula4. This sign, although less specific to an enterouterine fistula as compared with the aforementioned two examination techniques, was positive in the present case. Conventional examination of the colon using techniques such as barium enema and colonoscopy could detect diverticulosis, however they may not detect a fistula1–4.

Identifying a fistula tract is important for the planning of surgical management. According to previous reports, antegrade approaches to a fistula tract described above seem not to be suitable for demonstrating the tract because it is too small to be detected1–4. Therefore, retrograde approaches such as hysterosalpingography and sonohysterography are more useful. The use of a highly echogenic, sonographic contrast medium allows a very small volume to be used so as to avoid intra-abdominal spread of infection.

In summary, here we report a case of a colouterine fistula caused by diverticulitis, which was successfully diagnosed by sonohysterography and the charcoal challenge test. While the charcoal challenge test is reliable, safe and inexpensive, it does not locate the fistula tract specifically. Sonohysterography with contrast medium demonstrated the path of the fistula, the diverticular abscess and the involved organs. The combination of both tests is relatively inexpensive, safe and well tolerated by the patient, and is therefore recommended for establishing the diagnosis in the case of a presumed colouterine fistula.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report
  5. Discussion
  6. References
  • 1
    Huettner PC, Finkler NJ, Welch WR. Colouterine fistula complicating diverticulitis: charcoal challenge test aids in diagnosis. Obstet Gynecol 1992; 80(3Pt2): 550552.
  • 2
    Chaikof EL, Cambria RP, Warshaw AL. Colouterine fistula secondary to diverticulitis. Dis Colon Rectum 1985; 28: 358360.
  • 3
    Davis AG, Posniak HV, Cooper RA. Colouterine fistula: computed tomography and vaginography findings. Can Assoc Radiol J 1996; 47: 186188.
  • 4
    Kiyokawa K. A case of sigmoidouterine fistula detected by transvaginal ultrasonography. J Med Ultrasonics 2001; 28: 7175.
  • 5
    Lal SK, Clark PD, Becker JM, Farraye AF. Colouterine fistula. Am J Gastroenterol 2002; 97: 24732474.
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  • 6
    Smalley MA, LoRusso V, O'Brien JE. Sigmoidouterine fistula complicating diverticulitis: report of a case. JAMA 1957; 165: 827828.
  • 7
    Hershey SJ. Enterouterine fistulas: report of a case of cervicosigmoidal fistula. Obstet Gynecol 1959; 14: 234238.