Unique case of colovesical fistula in a renal allograft recipient
- Supradeep Narayanaswamy ,
- Rajvi Goradia ,
- Sachin Bhujbal and
- Sujata Patwardhan
- Urology, Seth GS Medical College and KEM Hospital, Mumbai, Maharashtra, India
- Correspondence to Dr Supradeep Narayanaswamy; vidvathpriya@gmail.com
Abstract
Colovesical fistula is commonly suspected in cases of diverticular disease, malignancy, trauma, iatrogenic injury or radiotherapy. In a case of allogenic live related transplant, this is rarely expected, especially after 20 years. The presence of gas in the bladder in the absence of history of instrumentation of urinary tract should prompt us to evaluate for colovesical fistula. Pneumaturia, faecaluria and recurrent urinary tract infection are tell-tale features of colovesical fistula, and when patients who are renal allograft recipient present with them, it should prompt a proper workup and swift surgical management, since the outcome is uniformly favourable. From our knowledge in this realm, we know that these are immunocompromised patients and have a high tendency to develop risk factors like malignancy and/or diverticular disease and eventually form colovesical fistula. An expected time period could be from 2 months to 6 years. But in our case, fistula formation occurred long after peak corticosteroid action, in the absence of conventional aetiologies.
Background
A colovesical fistula is an abnormal communication between the large bowel and urinary bladder. It usually occurs secondary to large bowel diverticular disease, malignancy or inflammatory bowel disease. Colovesical fistula in a renal allograft recipient is very rare and only five cases have been reported in the English literature.1–5 Diagnosis and management in such rare cases are challenging, due to the infrequency of presentation and diagnosis.6 We report a case of a woman in her 40s, who was diagnosed with colovesical fistula 20 years after receiving a renal transplant. The aim of this case report is to review the existing literature on colovesical fistulae after renal transplantation.
Case presentation
A woman in her 40s, who was a live related (mother to daughter) renal allograft recipient on immunosuppressive therapy, presented to our nephrology clinic with right iliac fossa pain, fever and burning micturition for 10 days. She underwent renal transplant in 2002 for end-stage renal disease due to focal segmental glomerulosclerosis (FSGS). She was treated with a high dose of steroids for severe acute rejection in the immediate postoperative period. Biopsy was performed on graft kidney after she had graft dysfunction. Her serum creatinine had elevated to a level of 1.92 mg/dL from a nadir level of 1.02 mg/dL. Biopsy report showed recurrence of the disease (FSGS) in the grafted kidney. In the past, she was treated for miliary tuberculosis and was conservatively managed for avascular necrosis of both hips. She had no history of any colonic diverticular disease or any malignancy. She did not have diabetes mellitus, or history of any surgical intervention on abdomen or pelvis other than renal transplant. She was unmarried and had no children. At presentation, she was on oral prednisolone 7.5 mg and 5 mg once daily dose on alternate days. Clinical examination was unremarkable, and the patient was haemodynamically stable. She underwent CT scan of the abdomen and pelvis, which revealed gas in the bladder and within pelvicalyceal system of grafted kidney, which was misinterpreted as emphysematous pyelonephritis of the grafted kidney and emphysematous cystitis. She was started empirically on intravenous piperacillin 4000 mg and tazobactam 500 mg three times a day for 14 days. Urine culture revealed Escherichia coli, which was sensitive to piperacillin–tazobactam combination. She was discharged after 14 days of intravenous antibiotics. She returned 20 days later with pneumaturia, passing foul-smelling muddy urine and burning micturition. Clinical examination was still unremarkable.
Investigations
Complete blood workup was done along with urine culture and sensitivity and CT scan of the abdomen and pelvis. Her white cell counts were 11.2X109/L, haemoglobin was 87 g/L and her creatinine was 1.7 mg/dL on admission. She had a serum iron level of 53 µg/dL, transferrin saturation of 33% and total iron binding capacity of 161 µg/dL. Her stool was positive for occult blood. She had also been treated for a Mallory-Weiss tear. Based on this preliminary examination, she was diagnosed with iron-deficiency anaemia. A repeat CT scan with per-rectal contrast revealed gas in the bladder with flow of contrast from the colon into the bladder suggesting the presence of colovesical fistula (figure 1). Colonoscopic examination revealed two fistulous openings, 33 cm and 37 cm, from the anal verge. There was no evidence or suspicion of any diverticular disease, inflammatory bowel disease or malignancy. Cystoscopy showed mild inflammatory changes in the right posterolateral wall of bladder with few pus flakes on the floor of the bladder. The ureteric orifice of the transplanted kidney was normal. There was no evidence of any fistulous opening in the bladder.
CT scan showing gas within bladder.
Treatment
She was started on intravenous meropenem 1000 mg three times a day and intravenous metronidazole 500 mg three times a day. The patient was taken up for explorative laparotomy where a fistulous communication between sigmoid colon and dome of the bladder was found (figure 2). Management of the involved bowel segment was done as per surgical gastroenterologist’s advice. Wedge resection of the involved segment of sigmoid colon was performed. The enterotomy was closed in two layers. The involved part on the dome of the bladder was excised (figure 3). The ureteric orifice of the transplanted kidney was healthy and away from the fistula site (figure 4). Bladder repair was performed in two layers (figure 5). Per urethral catheter was kept, which was removed on the 10th postoperative day. The immediate and early postoperative periods were uneventful, and the patient was discharged on the 14th postoperative day. Histopathology of the fistulous tract revealed florid giant cell granulation around vegetative matter and crystalline material that resembled suture material. There was no evidence of tuberculosis or any malignancy.
Intraoperative visualisation of the fistula between dome of bladder and sigmoid colon.
Intraoperative picture of bladder (black arrow) and colon (green arrow) after separation.
The inner mucosal view of the bladder. Ureteric orifice of the graft kidney (indicated by black arrow) is uninvolved and well away from the fistula site (not seen in the image).
Cystotomy site after closure in two layers with Vicryl 2-0 sutures.
Outcome and follow-up
At discharge, she was started on oral azathioprine 100 mg once daily dose and oral ciclosporin 50 mg two times per day dose in view of persistent proteinuria along with prednisolone, which she was already receiving. Along with that, for treatment of her iron-deficiency anaemia, she was also started on iron supplements and given subcutaneous injections of erythropoietin (10 000 units). At present, she is doing well with oral prednisolone 5 mg once daily and oral azathioprine 50 mg once daily. Her most recent haemoglobin was 102 g/L. At 12-month follow-up, the patient was asymptomatic with stable graft function.
Discussion
Colovesical fistula is a very rare condition and most commonly occurs secondary to diverticulitis. Common presentations include pneumaturia (60%–80%), faecaluria (30%–50%), dysuria (30%–50%), flank pain, diarrhoea and haematuria.7 Though pneumaturia is not specific to the colovesical fistula, more than two-thirds of patients with colovesical fistula report passing ‘gas’ in the urine. Faecaluria is pathognomonic of colovesical fistula but is usually a late finding and occurs when the fistulous tract has become quite large.8 Physical examination in these patients is often unremarkable. Urinalysis and urine culture may not reveal any specific abnormality. Growth in urine culture is polymicrobial and non-specific.
Patients who present with features suggestive of fistula undergo various diagnostic modalities like cystography, barium enema, cystoscopy, colonoscopy and contrast-enhanced CT, which may help to clinch the diagnosis.9 The diagnostic yield of these modalities is highly variable. CT scan has accuracy greater than 90% in diagnosing a case of fistula. Findings on CT suggestive of fistula include the presence of intravesical gas, presence of contrast in the bladder and thickening in the bladder wall adjacent to bowel loops with loss of fat plane between them. Cystoscopy is reliable but not all cases will be diagnosed with the same, as in our case.10 Demonstration of the fistulous opening is the direct way to diagnose a case of colovesical fistula. Presence of gas within the bladder and irregularity of the bladder wall, which gives a nodular appearance or rarely appearance of intravesical filling defect on cystogram, point towards colovesical fistula.
Management requires surgical excision of the fistulous tract followed by primary repair of the bowel and the bladder. All unhealthy tissue surrounding the fistula should be removed before repair to ensure good healing.
Colovesical fistula in renal allograft recipients is very rare and only five cases have been reported. We reviewed all the five reported cases (table 1). The patient details of one case were absent. Two cases presented within 6 months of renal transplantation, while two other cases presented after 3 years and after 5 years.
Previous five published case reports in literature on colovesical fistula in transplant recipients
| Author | Patient details | Clinical features | Radiological finding | Intraoperative findings | Procedure | Cause of fistula | Outcome |
| Lao and Bach3 | – | – | Barium scan diverticulitis with gas in bladder | – | – | Secondary to diverticular disease | Survived |
| Rodrigo et al 5 | Man in his 50s, recipient of cadaveric transplant | Fever, dysuria, pneumaturia, 2 months after renal transplant | Gas within the bladder with adjacent bowel loops; there were many diverticula with inflammatory sign in the colon Barium enema: diverticular disease affecting sigmoid and descending colon |
Colovesical fistula between sigmoid colon and dome of the bladder wall | Fistula was excised, bladder wall repaired, affected part of sigmoid colon resected and end-to-end anastomosis performed | Secondary to diverticular disease | Survived |
| Imafuku et al 2 | Man in his 50s, recipient of cadaveric renal transplantation | Fever, frequent urination and pyuria; history of diverticulitis of sigmoid colon for which resection of sigmoid colon and temporary colostomy done, 5 months after renal transplantation | Non-contrast CT scan: gas in the bladder Gastrograffin enema: passage of contrast medium into the bladder from the sigmoid colon |
Sigmoid colovesical fistula; sigmoid colon was tightly adherent to the bladder and pelvic wall | Partial sigmoidectomy with Hartmann procedure | Secondary to surgery done for diverticular disease | Survived |
| Subbiah et al 4 | Man in his 40s, recipient of living unrelated donor renal transplantation | UTI with pneumaturia and faecaluria, 5 years after renal transplantation | Thickened sigmoid colon with contact with bladder wall and loss of fat plane between them; no evidence of diverticular disease or malignancy | Colovesical fistula between sigmoid colon and dome of bladder | Sigmoidectomy with colorectal anastomosis with diversion ileostomy; involved part of the dome of bladder wall was excised and repaired | Details not available | Survived |
| Elenin et al 1 | Woman in her 70s, recipient of cadaveric renal transplantation | Pneumaturia with features of UTI, history of recurrent UTI, 3 years after renal transplantation |
CT scan: extensive diverticulosis of sigmoid colon, colovesical fistula with gas in the bladder and in the grafted renal pelvis | Details not available | Details not available | Secondary to diverticular disease | Patient succumbed due to midgut gangrene secondary to superior mesenteric vessel thrombosis |
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UTI, urinary tract infection.
Four out of these five patients had diverticulitis of sigmoid colon as the cause of colovesical fistula. The use of immunosuppressive agents in these patients will reduce the severity of diverticulitis and diagnosis is often delayed. Many times, the diverticular abscess goes unnoticed due to suppressed immunological reaction due to use of immunosuppressants, and these patients end up with a colovesical fistula. Five out of five patients had urinary tract infection (UTI) and pneumaturia. Though use of immunosuppressants increases the risk of UTI in renal allograft recipients, recurrent UTI should raise suspicion of colovesical fistula. Presence of pneumaturia in the absence of recent cystoscopy and faecaluria along with UTI is pathognomonic of fistula and should be sought in these patients with recurrent UTI. Risk of malignancy in renal transplant patients is more, and malignancy is a risk factor for fistula. In the five patients, none, including our patient, had any malignancy.
Cause and events leading to the colovesical fistula were not identified in our case. Our differentials were mainly two, the first being genitourinary tuberculosis. The diagnosis of tuberculosis was retrospective and based on the history of miliary tuberculosis she had suffered and the histopathological report of lymphocytes and multinucleated giant cells in resected specimen. However, it was discarded as there was no radiological or microbiological evidence of tuberculosis. Our second differential was clinically asymptomatic sigmoid diverticulitis with progression to abscess formation with involvement of adjacent bladder. The specimen excised was evaluated by two surgical pathologists. Both the reports concluded that the sample was negative for tuberculosis. Even though the clinical picture was not leaning towards adenovirus or BK virus cystitis, we performed microbiological examination of blood, urine and resected specimen for these viruses. PCR results for urine and serum adenovirus were negative. BK virus PCR quantitative test and urine examination for decoy cells were negative for BK virus cystitis. Urine culture was positive for E. coli. One other case reported by Subbiah et al also had no apparent cause and the patient presented 5 years after renal transplantation.4 Time of presentation in the five reported cases ranged from 2 months to 5 years. Our case presented 20 years after renal transplantation. To our knowledge, this is the first case of colovesical fistula in a renal allograft recipient nearly 20 years after surgery. Presence of gas in the bladder should prompt us to evaluate for colovesical fistula in renal allograft recipients though the patient might not have risk factors. Management of colovesical fistula can be conservative in small fistulae but majority require surgical intervention, which is the gold standard for treatment and has good outcomes.11 12
Patient’s perspective
Being a transplant patient, I am used to continuous trips to the hospital. I am extremely regular with my nephrology follow up. This happening after 20 years was a shock to me and my family. My complaints of faeces and gas in my urine were extremely confusing and embarrassing to me. I could not understand what was happening to me for the first couple of days, let alone explain it to my doctor.
When I had to get readmitted after antibiotics and told that I require surgery, I was apprehensive. I was worried this would affect my daily functions and transplanted kidney. The doctors explained that it was a rare complication but they were confident in being able to fix it.
After my operation, it took me a while to start feeling better. When I finally ate a bite of solid food again, I was overjoyed. Over the course of my stay, my complaints were no more distressing. The doctors ensured I had everything I needed and alleviated my fears of recurrence, while discharge. I am currently on regular yearly follow up with the nephrology and urology team.
Learning points
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Through this case, we wanted to highlight the fact that non-specific clinical features like dysuria and fever can often be misinterpreted as a simple urinary tract infection (UTI) and treated as one. We wanted to impress upon the fact that such non-specific symptoms can be due to other less common causes like colovesical fistula, particularly when these features fail to get resolved with a prompt intravenous or oral antibiotic therapy.
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Renal transplant recipients are immunocompromised patients and have a high tendency to develop risk factors such as malignancy and/or diverticular disease, which might eventually lead to formation of colovesical fistula. These disease processes can remain asymptomatic as these patients are on immunosuppressants.
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The fistula formation usually occurs at peak corticosteroid action, when diverticulitis or other conventional aetiologies are clinically not expressed, although the underlying pathology continues to evolve, ultimately leading to fistula.
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An expected time period could be from 2 months to 6 years. But in some cases as our own, fistula formation can occur long after in the absence of conventional aetiologies and will need to be included in the differential diagnosis when a simple UTI fails to resolve with prompt antibiotic treatment.
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Pneumaturia and faecaluria are classic features of colovesical fistula. However, some patients might present with non-specific features like recurrent or unresolved UTI and gas within bladder and pelvicalyceal system, which in the absence of recent instrumentation, should raise suspicion of colovesical fistula particularly in predisposed population.
Ethics statements
Patient consent for publication
Footnotes
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Contributors The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content—SN, RG, SB and SP. The following authors gave final approval of the manuscript—SN, RG, SB and SP.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.
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