Since first being described in 1908 [1], over 100 reports on UAF have been published to date [2] and its incidence will increase due to more frequent use of indwelling ureteral catheters because of the recent increase in cancer survivors [3]. UAF can occasionally be fatal with a mortality rate of 20–30% even in the modern era [4,5,6]. Eighty-five percent of UAFs are reported to be a secondary etiology after pelvic surgery or radiation [7], and cervical cancer is one of the most frequent causes of the disease [2, 4]. Our case had several other risk factors for UAF, such as a history of a chronic indwelling ureteral stent, repeated urinary tract infections, and diabetes mellitus as comorbidities. Furthermore, the autopsy confirmed the local recurrence of cervical cancer, which had never been detected during the postoperative surveillance. Those combined risk factors might have caused chronic pressure between the ureter and left internal iliac artery branch resulting in histopathological ischemic changes. In addition, it was considered that the pre-existing uretero-colic and uretero-vaginal fistulas contributed to this sudden fatal outcome. Because the left ureter had already become connected to the extracorporeal space through these fistulas, bleeding from the newly developed UAF spreads out through that route without a tamponade effect. Therefore, a prompt diagnosis and treatment were quite essential especially in our case.
Endovascular management has been widely used as the main treatment strategy for UAFs over a traditional open repair [8,9,10,11] and also has been successfully applied to the treatment of arterio-enteric fistulas [12, 13]. It would be promising to enable immediate hemostasis with less morbidity than surgical treatment, especially in patients who had prior pelvic interventions and a vascular pathology.
Despite these recent advances in the treatment modalities, diagnosing UAF is still a clinical challenge, and a diagnostic delay has been reported to be associated with a significantly poor outcome [14,15,16].
Although contrast CT, cystoscopy, and standard angiography have been employed as diagnostic modalities, the clinical utility or sensitivity are far from satisfactory and the diagnosis is often made at the time of surgery [2, 15, 17]. In addition to the lack of awareness of the etiology, even the most sensitive angiography could often fail to visualize extravasation into the ureter due to intermittent bleeding and the presence of an indwelling ureteral stent [2, 18, 19]. To improve the diagnostic accuracy, pharmacological provocative maneuvers other than standard angiography have been provocative angiography in which the indwelling ureteral stent is removed to help visualize the fistula [6, 14, 18, 20]. Contrast-enhanced CT was not diagnostic even after the onset of the bleeding in our case and therefore angiography including provocative maneuvers might have helped obtain a correct diagnosis. However, because stent manipulation not only can be diagnostic but also cause massive bleeding [21, 22], provocative angiography should be attempted with simultaneous arterial embolization or surgical bypass grafting [6]. Further, it was considered that to suspect a UAF by itself was a key issue. Considering the history of pelvic interventions including chemoradiotherapy and chronic indwelling ureteral catheters requiring routine exchanges due to repeated urinary tract infections, we should have suspected the possibility of the UAF during the earlier stage of the workup in our case.
