Iatrogenic enterovesical fistula secondary to a permanent urinary catheter

Abstract

An enterovesical fistula is a rare entity resulting from inflammatory, neoplastic and iatrogenic processes. It can manifest clinically as pneumaturia and recurrent urinary tract infections. Its diagnosis is supported by imaging examinations and its treatment is primarily surgical.

Background

An enterovesical fistula is defined as an abnormal connection between the small intestine and the urinary bladder. This condition, however, remains relatively unknown. Classic symptoms include pneumaturia, faecaluria and passage of urine through the rectum. Enterovesical fistula can result from inflammatory processes such as in acute diverticulitis and Crohn’s disease, or from neoplasms such as bladder cancer. Permanent urinary catheterisation is a rare cause of enterovesical fistula, with few cases described in the literature. Early diagnosis and treatment is essential to prevent the morbidity and mortality associated with this condition.

Case presentation

A woman with a medical history of type 2 diabetes mellitus, chronic kidney disease and stage IIIB squamous cell carcinoma of the cervix, with a complete response to four cycles of cisplatin–gemcitabine regimen and radiotherapy, presented with bilateral obstructive uropathy. She had developed renal failure and vesicoureteral reflux 2 years before admission and was under urology care with a double J stent colocation and 16 Ch silicone permanent urinary catheter with frequent replacements. The exchange of catheter is being carried out every 3 months in the community, and there had been no reported difficulties with previous catheter changes. She presented to the emergency department complaining of urine discolouration following a recent change of urinary catheter at her local health centre earlier that day. She denied fever or previous urinary tract infections.

On assessment at the emergency department, the patient was haemodynamically stable and afebrile, presenting with a soft, non-tender abdomen without signs of peritoneal irritation. There was no suprapubic pain on palpation. Her body mass index was 24.8. The urinary catheter was correctly placed and the presence of faecaluria was noted.

Investigations

Laboratory tests revealed a normal white cell count of 7.620×10⁹/L with a standard differential count, a stable haemoglobin level of 9 g/dL and an unremarkable coagulation profile. Creatinine level was elevated at 1.6 mg/dL, with a glomerular filtration rate of 45 mL/min (baseline). Additionally, C reactive protein level was elevated at 4.3 mg/L.

Urinalysis revealed turbid brown urine with elevated bilirubin of 6 mg/dL and urobilinogen level of 8 mg/dL; leucocyte esterase level was positive, while heme/myoglobinuria was notably absent. Urine sediment exhibited high levels of leucocytes at 220–300 per high-power field and red blood cells at 60–90 per high-power field, along with abundant mucus and the presence of bacilli of 48 per high-power field.

Abdominopelvic CT scan revealed the urinary catheter and its balloon within the small intestine loop adjacent to the bladder dome (figure 1); contrast material was clearly visible within the small intestine loops. A small amount of free fluid was observed in the pelvic region, dispersed between the intestinal loops and the subhepatic and perisplenic regions, presumably attributable to the fistula. Bilateral grade IV hydronephrosis was evident, and bilateral double J catheters were also in place.

Figure 1.

Abdominopelvic CT scan revealing the urinary catheter and its balloon within the small intestine loop (arrow) adjacent to the bladder dome, with contrast present in the small intestine loops: (A) axial cut and (B) coronal cut.

Treatment

The patient was admitted and her case was discussed with a multidisciplinary team comprising urologists, general surgeons, anaesthesiologists and nephrologists. Intravenous antibiotic therapy with ceftriaxone and metronidazole was initiated, and surgical intervention was planned to repair the enterovesical fistula. A joint procedure was performed by urologists and general surgeons. Intraoperative findings revealed an enterovesical fistula with an intraluminal vesical balloon attached to the small intestinal loop, adhering to the vesical dome (figure 2). The balloons and loops were carefully dissected and separated. A 1 cm vesical orifice was closed in two layers using 0 polysorb sutures. The integrity of the closure was checked with a physiological saline solution. The small intestinal loop with the perforation was resected, and an isoperistaltic side-to-side anastomosis was made. An omentum flap was fashioned and affixed to the vesical dome using 0 polysorb sutures. A Blake drain (15 mm) was placed.

Figure 2.

Intraoperative findings: (A) intestinal loop (arrow) adhering to the dome of the bladder, (B) 1 cm hole (arrow) in the bladder dome and (C) segment of the small intestine with perforation (arrow).

Enterovesical fistula presents significant challenges in the daily practice of urologists due to its rarity, the need for a multidisciplinary collaboration and the involvement of different hospital departments. Presurgical preparation is crucial to their management. In the present case, the possibility of access to abdominopelvic CT allowed presurgical planning and smooth execution of the surgery without complications, resulting in the resection of a shorter length of the small intestine and successful bladder suturing. During the postoperative period, collaborative management with the departments of nephrology and general surgery led to a favourable surgical outcome, enabling discharge of the patient with periodic bladder catheter replacement. This case underscores the importance of teamwork in addressing and managing unusual cases effectively.

Outcome and follow-up

The postoperative course progressed favourably without complications. The patient remained afebrile, had well-controlled pain with scheduled analgesia, tolerated a regular diet, had normal bowel movements and had clear urine drainage through the urinary catheter. She was discharged on the eight postoperative day and is currently undergoing regular follow-up at the urology outpatient clinic. She was referred to a nephrologist and an oncologist for chronic renal failure and cervical carcinoma follow-up.

Discussion

A fistula is an abnormal connection between two epithelial surfaces. However, there are some exceptions to this definition, such as when the surfaces are not epithelial as in the endothelial surfaces of vascular fistulas. The fistula often starts from an offending side and makes its way to an adjacent lumen or surface. Fistulas are named according to the surfaces or organs they connect, such as enterovesical fistula.¹ The condition is quite rare, occurring mainly in the sixth and seventh decades of life, with a high male to female ratio (3:1). It is estimated to occur in approximately 1 in every 3000 surgical hospital admissions.²

The term enterovesical fistula refers to an abnormal communication between the intestinal mucosa and the bladder. It is categorised into distinct clinical entities, including jejunovesical, ileovesical, colovesical, sigmoid-vesical or rectovesical fistula, based on the specific part of the intestine affected.^{3 4}

Colovesical fistula (CVF) is an abnormal communication between the bladder and the large intestine, usually the sigmoid colon. It accounts for approximately 95% of enterovesical fistula.⁵ According to the literature, the most common aetiology of CVF is diverticular disease, the primary mechanism being the result of a surrounding inflammation or the direct extension of ruptured diverticula or secondary erosion of a diverticular abscess into the bladder. CVF predominantly occurs in men and rarely in non-hysterectomised women; in women, the uterus serves as a protective anatomical barrier against the inflammatory process that induces fistula formation.^{6 7} Consequently, CVF is a well-recognised complication of diverticulitis. The high prevalence of diverticular disease contributes to a rise in CVF cases.^{7 8}

Enterovesical fistulas are complications arising from an underlying primary diseases of the bowel, bladder or other pelvic organs. They typically originate from the intestine, with those originating from the bladder wall being rare. Most cases occur in patients with acute diverticulitis (70%), Crohn’s disease (10%) or malignant neoplasms (10%). Other less common causes include acute appendicitis and enterovesical fistulas resulting from erosion of the urethral catheter through the bladder wall into the bowel lumen. We reviewed the literature and found the causes of fistula (table 1).^9–15

Table 1.

Reports of causes of enterovesical fistula in the literature

Number	Year	Authors	Causes of enterovesical fistula
1	2009	Melchior et al9	Acute diverticulitis
2	2015	Sellers and Fiorelli10	Malignant neoplasm
3	2000	Yamamoto and Keighley11	Crohn’s disease
4	2018	Iwamuro et al12	Radiation
5	2002	Venn and Mundy13	Trauma and iatrogenic injuries
6	2016	Alis et al14	Acute appendicitis
7	2014	Amend et al15	Foreign bodies: urinary catheters

The present case had a history of pelvic radiotherapy for treatment of carcinoma of the cervix. It has long been recognised that enterovesical fistula can be malignant and that previously irradiated areas increase the risk of developing fistulas.¹² Enterovesical fistula is a rare complication of pelvic radiation and can occur in the absence of tumour recurrence.¹⁶ However, intraoperative findings in this patient revealed an enterovesical fistula with an intraluminal vesical balloon attached to the small intestinal loop, adhering to the vesical dome. Therefore, in this patient, the permanent urinary catheter was the cause of the enterovesical fistula.

There are two main types of urinary catheter: intermittent silicone catheters, which are temporarily inserted into the bladder and removed once the bladder is empty; and indwelling catheters, which are designed to remain in place within an organ or passage for an extended period and are held in position by an inflated balloon in the bladder. Indwelling urinary catheters are either inserted transurethrally or suprapubically. Both methods of indwelling catheterisations are associated with complications.^{17 18}

Permanent urinary catheterisation has numerous known complications, as can be seen in table 2.^{16 19–25}

Table 2.

Complications of urinary bladder catheters

Number	Year	Authors	Complication	Incidence
1	2003	Keerasuntonpong et al20	Catheter-associated UTI	Symptomatic UTI: 10%–13% Asymptomatic UTI: 36%
2	2009	Hawary et al16	Enterovesical fistula	Unknown (rare)
3	2010	Stickler and Feneley19	Catheter blockage encrustation and blockage	Up to 50%
4	2013	Hollingsworth et al24	Urethral bleeding	1%
5	2016	Garg et al25	Urethral erosion (‘catheter hypospadias’)	Unknown (rare)
6	2023	Agrawal et al21	Purple urine bag syndrome	27% in institutionalised patients on long-term urinary catheters
7	2021	Hird et al23	Chronic inflammation, metaplasia and cancer risk	1.1%
8	2023	Spoolder and Geelhoed22	Bladder spasms (causing pain and urinary leakage)	5%

UTI, urinary tract infection.

In this patient, the permanent urinary catheter was inserted transurethrally by urologist indication 2 years before admission. There is no evidence of enterovesical fistula formation due to the suprapubic catheter. Perhaps the suprapubic catheter would have made a difference in fistula formation.

When performed properly, complications from suprapubic catheter placement are uncommon. Complications associated with initial placement include cutaneous or bladder bleeding and bowel injury, which are more common if suprapubic catheter placement is attempted when the bladder is not fully distended. Bowel injury after a routine change of a suprapubic catheter has been reported.²⁶

In this case, there was a history of radiotherapy for carcinoma of the cervix, which did put her in a high-risk category for developing an enterovesical fistula, as a result of a urethral catheter eroding through the bladder wall into the bowel lumen. Enterovesical fistula starts with inflammatory changes in the bladder wall originating from chronic pressure of a foreign body (catheter balloon), which can promote perforation and small bowel fistulisation. The pathological process of the formation of a fistula is seen in figure 3.

Figure 3.

Pathological process of fistula formation in this particular case.

The occurrence of enterovesical fistula as a complication of indwelling Foley catheters is exceptionally rare but warrants attention as a potential complication associated with use of these catheters. However, studies on this topic are limited. Hawary et al¹⁶ reported a case in which an enterovesical fistula developed as a rare complication of an indwelling urethral catheter. Chronic urethral catheterisation has shown to cause inflammatory changes within the bladder wall, which can promote perforation and small bowel fistulisation.^{15 27}

Clinical presentation

Symptoms of enterovesical fistula can originate from both the urinary and gastrointestinal tracts. However, most patients present with urinary symptoms including pneumaturia, faecaluria, increased frequency and urgency of urination, suprapubic pain, recurrent urinary tract infections, and haematuria.²⁷ The triad of pneumaturia, faecaluria and recurrent tract infections is considered pathognomonic.^{5 9 27} However, classic urinary symptoms are evident in only 50% of patients.⁴ In colonic diverticular disease, pneumaturia and urinary tract infections are the most common, whereas this is less likely with small bowels.⁵ There was no evidence linking pneumaturia to an increased risk of sepsis. Najjar et al⁵ observed less specific findings such as urinary tract infections, dysuria, urinary frequency and haematuria, or a combination of these findings in CVF, resulting in a delay in diagnosis due to CVF not being seriously considered. In addition, patients may exhibit symptoms related to the underlying disease causing the fistula. For instance, in patients with fistulising Crohn’s disease, abdominal pain, abdominal masses and abscesses are more frequent.^{27 28}

Diagnosis

Diagnosis is often delayed by several months from symptom onset. Radiological imaging aids in identifying the location of the fistula and its underlying causes.⁵ CT is the preferred imaging modality for diagnosing enterovesical fistulas and is particularly effective in detecting pericolic complications of diverticular diseases. Its use in CVF is well established and its sensitivity and specificity reach up to 100%.^{9 27 29} CT findings suggestive of an enterovesical fistula include the following:

• Air in the bladder (in the absence of prior instrumentation of the lower urinary tract).

• Oral contrast material in the bladder in non-intravenous enhanced scans.

• Presence of colonic diverticula.

• Thickening of the bladder wall adjacent to a thickened loop of bowel.^{27 29}

MRI allows precise delineation of fistulous tracts; however, it is limited by the high cost and limited availability in emergency settings, making it more suitable for complex elective cases.²⁷

Cystoscopy can be a helpful component of the diagnostic evaluation. It permits direct visualisation of the bladder and enables the physician to obtain a biopsy to check for malignancy. The presence of a localised area of oedema and congestion is a typical finding in the early stages of a fistula. Lesions are most commonly observed on the dome of the bladder. A lesion on the left dome of the bladder is typically diverticular, while a lesion on the right posterior wall or the right dome of the bladder is more likely associated with Crohn’s ileitis or an appendicovesical fistula.^{30 31}

Cystoscopy and colonoscopy are top diagnostic tools and could be useful in identifying the fistula. Nevertheless, cystoscopy fails to identify CVF in up to 50% cases, while colonoscopy records an identification rate for CVF not exceeding 55%.⁷

Treatment

Management of an enterovesical fistula involves managing the fistula and treating the underlying disease. Thus, establishing the aetiology of the fistula before determining the treatment approach is essential. Other factors such as the type of fistula, the patient’s general condition and the complications resulting from the fistula are important.³²

Control of sepsis

It is recognised that without surgical intervention 75% of patients may die from sepsis within 5 years. In this patient, the presence of faeces in the urine may lead to recurrent urinary tract infections and sepsis.^{4 16} Control of sepsis is important; therefore, intravenous antibiotic therapy with ceftriaxone and metronidazole was initiated and a surgical intervention planned to repair the enterovesical fistula.

Nutrition and physiological correction

Evaluation of nutritional status and nutritional support is important and necessary in patients with long-time enterovesical fistula.³³ Malnutrition contributes to a cascade of adverse metabolic events that compromise the immune system and impair the body’s ability to adapt, recover and survive during infection and sepsis. Also, it is necessary to treat hydroelectrolyte losses and correct hypovolaemia and electrolyte alterations. Correct replacement must be done with isotonic saline solution and potassium supplements.³⁴

Defining anatomy: imaging

The patient presented an enterovesical fistula. Abdominopelvic CT scan revealed the urinary catheter and its balloon within the small intestine loop adjacent to the bladder dome.

Planning the surgery

Surgical planning included a collaboration among urologists, anaesthesiologist and general surgeons.

1. Preoperative phase

• Patient evaluation and assessment of medical history, comorbidities and previous surgeries.

• Consultation between general surgery and urology departments to discuss the surgical approach.

2. Anaesthesia

• Anaesthesiologist evaluation for appropriate planning considering the patient’s condition.

3. Surgical procedure

1. General surgery team.

• Incision: a midline abdominal incision is made to access the affected area.

• Exploration: the intestines are carefully inspected to locate the enterovesical fistula.

• The following were the options:

Primary resection and anastomosis

Primary resection and anastomosis with a protective ileostomy high in the small bowel, with subsequent closure of the stoma.

1. Urology team.

• Bladder exposure and fistula identification: fistula repair: various techniques can be employed depending on the size and location of the fistula, including primary closure, layered closure or tissue interposition with omental flap or peritoneal grafts.

Surgical treatment

Treatment of enterovesical fistula includes non-surgical and surgical strategies. Non-surgical treatment is typically reserved for selected patients who are unfit for surgery. Surgical treatment has shown good results with a low rate of complications. The treatment approach is determined by the location of the intestinal lesion and the patient’s comorbidity. It involves resection and anastomosis of the damaged intestinal segment. Bladder repair is accomplished through primary closure.^{7 35}

Treatment may involve one or multiple stages. In the first stage, primary resection and anastomosis are performed without a protective colostomy, whereas in the second stage primary resection and anastomosis are performed with colostomy and/or Hartmann’s procedure (two-stage procedure), with subsequent closure of the stoma (three-stage approach). The one-stage surgical approach is preferred whenever possible, while the multistage procedure is reserved for cases with a pelvic abscess, advanced malignancy or previous radiation therapy. Faecal diversion may be necessary in case of peritonitis, in haemodynamically unstable patients, in patients with malnutrition and in those with sepsis.^{4 7 35} If faecal diversion was needed in the present case, we would do an ileostomy high in the small bowel.

Management of enterovesical fistula is technically challenging, requiring a multidisciplinary and interprofessional approach to ensure patient safety and achieve satisfactory results. A combined surgical approach involving collaboration between coloproctologists and urologists offers the most effective method of management.³²

Both open and laparoscopic approaches can be used in the management of enterovesical fistula. A laparoscopic approach may be feasible in well-selected and stable patients; however, this should be performed by experienced surgeons owing to a high conversion rate. Cystography can be used to evaluate the resolution of the leak. The Foley catheter must be removed after 7 postoperative days as prolonged use is associated with an increased rate of catheter-associated urinary tract infections and longer hospital stay.^{35 36} In the present case, the patient needed permanent urinary catheter with frequent replacements.

The patient’s fistula and the choice of management

In the present case, the patient had a history of gynaecological malignancy and was a carrier of a permanent bladder catheter with frequent replacements. During her last replacement, the presence of faecaluria was noted secondary to a fistula formation, assuming the catheter balloon exerted a pressure effect between the bladder and the small bowel. The diagnosis was established through CT scan, and surgical treatment included primary closure of the bladder and resection of the affected intestinal segment along with primary anastomosis.

A diagnosis of enterovesical fistula should be considered when handling patients with indwelling urethral catheters and history of radiotherapy and pelvic neoplasm.

Learning points.

• Iatrogenic enterovesical fistulas can occur as a complication of long-term urinary catheter use, highlighting the importance of proper catheter care and monitoring.

• Clinicians should be vigilant for signs and symptoms related to an underlying disease; in patients with colonic diverticular disease, pneumaturia and urinary tract infections are the most common, whereas these are less likely with small bowels.

• Prompt diagnosis and intervention is crucial to managing enterovesical fistulas to prevent further complications, including sepsis and kidney damage.

• Education of healthcare professionals and patients about the potential risks associated with long-term urinary catheter use is crucial to promote patient safety and minimise iatrogenic complications.

Ethics statements

Patient consent for publication

Obtained.