Entero Urinary Fistula EUF

It is well known that about one third of patients with CD have enteroenteric or enterocutaneous fistulas which are secondary to the characteristic transmural inflammation [58]. Fistulisation within the urinary system is also possible but it is much less common, occurring in 1-8% of cases [1, 3, 6,19, 59-62].

The majority of fistulas result from direct contact between inflamed terminal ileum and the bladder dome (ileovesical fistula). Sometimes an intervening abscess is present and in this case it is not unusual to find more than one intestinal segment involved in the fistula [63, 64]. Crohn's colitis, and more rarely UC, can determine a colovesical fistula which generally involves the sigmoid colon [59]. Severe rectal disease can cause rectourethral fistulas, but this is a rare event. Other unusual fistulas are those between the terminal ileum and ureter, or urachus.

In the widest series reported in the literature [65], fistula originated from ileum in 64% of cases, colon in 21%, rectum in 8% and multiple sites in 7%, while

Entero Vaginal Fistula

the involved urinary tract included the bladder in 88%, urethra in 6%, urachus in 3% and urether in

Entero-Urinary Fistula (EUF) are more frequent in men, with reported M:F ratio up to 9:1 [2,59]. This fact is explained via the anatomy of the female pelvis, where the bladder and the urethra are protected by the uterus and the vagina, respectively [19]. Fistulas tend to manifest in patients with established bowel disease [3, 59,60,63], often within the first decade of onset [65]. Not surprisingly, the concomitance of enteroenteric or enterocutaneous fistulas arising from the same segment of bowel is frequent [59, 60, 65, 66].

However, EUF has also been reported as the presenting manifestation in patients without a previous history of CD [59]. Prodromic symptoms or signs like dysuria, urinary urgency and frequency, suprapubic discomfort, microscopic or gross hematuria, are often present in early stage, indicating a status of perivesical inflammation [3, 60, 63,67].

When fistulisation has occurred, it usually manifests with pathognomonic signs like pneumaturia or faecaluria. Another specific but rare sign is the passage of urine through the rectum (urorrhea) [60, 67]. In a minority of cases, there is only a history of recurrent urinary tract infection (UTI) refractory to medical treatment, while very rarely the patient can be asymptomatic (Table 4) [65]. Pneumaturia has been reported with percentages varying from 38-94%. In the series from the Mayo Clinic it was present in 68% of patients (Table 4), but according to others [68], this sign is evident in more than 90% of cases and, when not noticed by the patient, air bubbles can be evident if he or she urinates while submerged in a bathtub.

The physical examination is often normal or it demonstrates symptoms and signs of the underlying pathology like tenderness in the lower abdomen, a palpable mass, enterocutaneous or perineal fistulas. Urinalysis reveals leukocytosis and microscopic hematuria in the majority of patients [65]. The culture is almost always positive for E. Coli, while polymicrobial infection is present in about one third of the cases [59, 63, 65]. Complications like pyelonephritis or other major infections are unusual, unless there is a direct communication with the ureter or abnormalities at the ureterovesical junctions [68].

Diagnosis of EUF can be obtained with an accuracy of 92% after oral or rectal administration of indo-cyanine green solution and urine examination using a colorimeter [69]. Diagnosis can be confirmed with imaging tests. A plane abdominal X-ray in erect position is sometimes sufficient for showing an air level into the bladder but this can be better demonstrated with a CT scan, which also allows the highlighting of other peculiar signs like the apposition of the thickened bowel and the bladder wall, a perivesical abscess or the presence of oral contrast into the bladder. For all these reasons, CT scan, which has an accuracy close to 100%, is considered the test of choice [70,71].

Table 4. Presenting symptoms in 78 Crohn's disease patients with entero-urinary fistulas. (Adapted from Solem et al. [65])


No. of patients








Recurrent UTIs






Hematuria (micro/gross)









Direct identification of the fistula opening at cystoscopy is reported in 7-74% of cases [3, 60, 65, 67], although usually this exam permits the visualisation of an area of bullous edema, erythema or papillomatous hyperplasia. Other findings are the presence of feculent debris or pus in the bladder. Some authors consider cystoscopy fundamental in the work-up of this pathology [60, 65, 72, 73], while others believe that it is an invasive procedure that poses a potential risk of spreading infection and, at the end of the day, does not provide information that is any more useful than imaging exams [68]. In fact, the most important thing in planning the correct management of an enterovesical fistula is not to see its opening in the bladder but rather to identify the segment of bowel involved in the inflammatory process [68].

Other urological investigations like cystograms and excretory urograms are only occasionally useful. Small-bowel follow through, barium enema and colonoscopy are suggested because, even if the fistula is rarely demonstrated, they help to determine the extent and nature of the underlying disease and to exclude other causes of EUF such as diverticular disease or colonic malignancies [59,67, 74, 75].

What the best management of EUF should be is still being debated. Although spontaneous closure has been described [63,67, 76], this event is very rare and most authors agree that the presence of EUF is a sign of complicated disease that indicates surgery. The operation usually consists of disconnection of the tract, resection of the affected bowel and suture of the vesical wall. Partial cystectomy is rarely necessary and was only needed for less than 10% of the patients operated on at The Mayo Clinic [65]. Postoperative morbidity and mortality was 6.4 and 1.6% respectively in a series of 61 patients, and fistula recurrence rate was 1.6% [60].

The advances in medical therapy with the dispos-ability of new immunosuppressive and anticorpal drugs has reinforced the opinion of those authors who believe that the fistula itself, considering its benign evolution and the low risk of ascending infection, does not require an operation and should first be managed conservatively, reserving surgery exclusively for when it is associated with intra-abdominal or pelvic abscesses or obstructive stricture of the bowel [66, 68, 77]. This is in contrast with the policy of the Mayo Clinic, where fistula alone represented the indication for surgery in 69% of their patients with EUF [65].

Medical treatment was effective in the long-term and surgery was avoided in six cases in a series of 17 patients (35%) [66]. At The Mount Sinai Medical Hospital [68], among 31 patients treated with sul-phasalazine, continuous antibiotics and 6-mercap-topurine when necessary, 18 (58%) had a clinical remission and 12 of them remained well for a mean period of 8 years. Patients not responding to medical therapy were more frequently those who were already steroid dependent. In another series of 43 patients, 20 (43%) were able to avoid surgery with a combination of 6MP, antibiotics and mesalamine [77].

However, although medical treatment has shown potential promise in some small series, there have not been any prospective studies designed specifically to assess the efficacy of the medical treatment of internal fistulas [78]. At the moment, surgery is still considered to be the treatment of choice and up to 95% of patients will eventually receive it [27, 63, 65, 79]. There are still no reports on infliximab, but its well-documented benefits in healing perineal, ente-rocutaneous [80, 81] and also rectovaginal fistula [82] should encourage studies on it. Prospective trials to define the exact role of medical and surgical therapy are also desirable.

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  • Retu Lilja
    How to determine pneumaturia in bathtub in bathtub?
    8 years ago
    What urine examinations can be done using colorimeter?
    8 years ago
  • howard
    How would a bladder to perineal fistula present itself?
    6 years ago

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