Uretero-Enteric Fistula - Symptoms, Causes, Treatment & Prevention

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Overview

A uretero‑enteric fistula (UEF) is an abnormal connection between a ureter (the tube that carries urine from the kidney to the bladder) and any part of the gastrointestinal (GI) tract—including the small intestine, colon, or rectum. Urine can leak into the bowel and, conversely, intestinal contents can enter the urinary system, leading to a wide range of symptoms and potentially serious infections.

UEFs are rare. Large case series from tertiary referral centers estimate an incidence of 0.01 %–0.1 % among patients who have undergone major abdominal or pelvic surgery. Most cases occur in adults aged 50–70 years, with a slight male predominance (approximately 60 % of reported cases). The condition is almost always acquired rather than congenital.

Symptoms

Symptoms result from the passage of urine into the bowel, bowel contents into the urinary tract, or infection. The clinical picture can be subtle or dramatic.

• Pneumaturia – bubbles or “fizzing” sensation when urinating due to gas from the intestine entering the urine.
• Fecaluria – presence of fecal material or a foul odor in the urine.
• Hematuria – blood in the urine, often intermittent.
• Dysuria – painful or burning urination.
• Recurrent urinary tract infections (UTIs) – especially with organisms typical of the gut (e.g., E. coli, Enterococcus, Proteus).
• Flank or abdominal pain – usually dull, may radiate to the groin.
• Lower abdominal or pelvic pain – can be confused with diverticulitis or colitis.
• Changes in bowel habits – diarrhea, urgency, or rectal bleeding if the colon is involved.
• Fever and chills – sign of systemic infection or sepsis.
• Weight loss & malnutrition – chronic inflammation and infection can reduce appetite.
• Perinephric abscess or pyonephrosis – collection of pus around the kidney.

Causes and Risk Factors

UEFs are almost always acquired. The most common etiologies are listed below.

1. Surgical injury

• Radical pelvic surgery – colorectal resection, hysterectomy, prostatectomy, or urinary diversion (e.g., ileal conduit) can inadvertently damage the ureter.
• Urological procedures – ureteroscopy, percutaneous nephrolithotomy, or endoscopic laser lithotripsy.
• Vascular surgery – aortic aneurysm repair (especially open repair) places the ureter at risk.

2. Radiation therapy

Pelvic or abdominal radiation for cancer (prostate, bladder, cervical, colorectal) leads to fibrosis and tissue necrosis, predisposing to fistulisation.

3. Inflammatory bowel disease (IBD)

Severe Crohn’s disease or ulcerative colitis can erode through the bowel wall and involve adjacent ureters.

4. Malignancy

• Advanced colorectal, ovarian, or cervical cancer directly invading the ureter.
• Urothelial carcinoma with extravesical spread.

5. Infection & abscess

Perinephric or retroperitoneal abscesses can erode into the bowel, creating a fistula.

6. Chronic indwelling ureteral stents

Long‑term stent placement (> 6 months) can cause pressure necrosis and ulceration of the ureteral wall.

Risk Factors

• History of major abdominal or pelvic surgery (especially within the past 5 years).
• Prior pelvic radiation (dose > 45 Gy).
• Active IBD or recent flare.
• Advanced intra‑abdominal malignancy.
• Diabetes mellitus, smoking, or immunosuppression (increase risk of infection and impaired healing).

Diagnosis

Because symptoms overlap with many other conditions, a high index of suspicion is essential, especially in patients with recent pelvic surgery or radiation.

1. Laboratory tests

• Urinalysis – pyuria, bacteriuria, and sometimes fecal material.
• Urine culture – often grows colonic flora (E. coli, Enterococcus, Klebsiella).
• Blood tests – CBC (leukocytosis), CRP/ESR (inflammation), serum creatinine (renal function).

2. Imaging studies

• CT abdomen/pelvis with contrast – gold standard. Shows contrast extravasation from ureter to bowel, air in the collecting system, or a tract between structures.
• Retrograde pyelography – catheter placed in the ureter; contrast outlines the fistula.
• Magnetic Resonance Urography (MRU) – useful when iodinated contrast is contraindicated.
• Ultrasound – may reveal hydronephrosis or perinephric fluid but is not definitive.

3. Endoscopic evaluation

• Cystoscopy & ureteroscopy – directly visualizes the ureteral orifice and any breach.
• Colonoscopy or sigmoidoscopy – identifies the bowel side of the fistula, especially if colonic.

4. Diagnostic criteria

A diagnosis is generally established when any two of the following are present:

1. Pneumaturia or fecaluria.
2. Imaging evidence of a communication between ureter and bowel.
3. Isolation of gastrointestinal organisms from urine.
4. Endoscopic confirmation of a fistulous opening.

Treatment Options

Management is individualized based on the patient’s overall health, the location of the fistula, and the underlying cause.

1. Initial medical management

• Broad‑spectrum antibiotics covering gram‑negative and anaerobic flora (e.g., piperacillin‑tazobactam, ceftriaxone + metronidazole) until cultures guide therapy.
• Fluid and electrolyte replacement – especially if there is significant urinary loss into the bowel.
• Urinary diversion – placement of a percutaneous nephrostomy tube or indwelling ureteral stent to bypass the fistula and allow healing.

2. Definitive surgical repair

Surgery remains the mainstay for most patients.

• Ureteral resection and primary anastomosis – removal of the fistulous segment and tension‑free end‑to‑end ureteral repair.
• Ureteroneocystostomy – re‑implantation of the ureter into the bladder, often used when the distal ureter is involved.
• Bowel repair – segmental resection of the affected bowel with primary anastomosis or creation of a diversion (e.g., ileostomy) if contamination is high.
• Use of tissue interposition – omental flap or peritoneal graft placed between ureter and bowel to reduce recurrence.
• Laparoscopic or robotic approaches – increasingly employed in elective cases; they reduce postoperative pain and length of stay.

3. Minimally invasive alternatives

• Endoscopic closure – placement of covered self‑expanding metal stents or fibrin glue for small, well‑localized fistulas.
• Percutaneous embolization – rarely used; embolic agents occlude the fistulous tract.

4. Adjunctive measures

• Nutrition optimization – high‑protein diet, oral supplements, or enteral feeding if malnourished.
• Smoking cessation and strict glycemic control in diabetics to improve wound healing.
• Removal of any chronic indwelling stents once the fistula is resolved.

Living with Uretero‑Enteric Fistula

Even after successful repair, some patients require ongoing care.

• Hydration – aim for >2 L of clear fluids per day to promote urine flow and reduce stasis.
• Urinary hygiene – clean perineal area after voiding; consider a mild antiseptic wash if recommended by your provider.
• Dietary adjustments – limit foods that cause excess gas (beans, carbonated drinks) which can exacerbate pneumaturia.
• Bladder training – scheduled voiding every 3–4 hours can lessen pressure spikes in the upper tract.
• Follow‑up imaging – CT or ultrasound at 3‑month intervals for the first year, then annually, to ensure no recurrence.
• Medication review – avoid chronic NSAIDs (risk of renal irritation) and maintain any prophylactic antibiotics only if truly indicated.
• Psychosocial support – the odor and unusual symptoms can cause anxiety; counseling or support groups (e.g., patient forums for complex urinary fistulas) are beneficial.

Prevention

Because many risk factors are iatrogenic, prevention focuses on careful surgical technique and postoperative care.

• Meticulous intra‑operative identification of ureters – use of real‑time fluorescence (ICG) or ureteral stents during high‑risk pelvic surgery.
• Radiation planning – conformal techniques (IMRT, VMAT) to spare ureters when possible.
• Prompt treatment of intra‑abdominal infections – early drainage of abscesses reduces erosion risk.
• Short‑term stenting – limit ureteral stent dwell time to <6 weeks when feasible.
• Control of chronic diseases – good glycemic control, smoking cessation, and weight management lessen tissue‑healing complications.
• Regular follow‑up after cancer therapy – surveillance imaging can detect early fistulous changes before they become symptomatic.

Complications

If left untreated, a uretero‑enteric fistula can lead to serious, potentially life‑threatening problems.

• Recurrent or severe urinary tract infections, often progressing to pyelonephritis.
• Sepsis – systemic infection with high mortality if not rapidly managed.
• Renal impairment – chronic obstruction or infection can lead to loss of kidney function (up to 30 % of cases develop irreversible damage).
• Electrolyte disturbances – loss of bicarbonate and potassium when large volumes of urine mix with bowel contents.
• Malnutrition and weight loss due to chronic inflammation and altered bowel function.
• Stricture formation – scarring of the ureter or bowel after healing can require further surgical correction.
• Fistula recurrence – reported in 10 %–20 % of surgically repaired cases, especially when tissue interposition was not used.

When to Seek Emergency Care

References

• Mayo Clinic. “Ureteral fistula.” Accessed May 2024. mayo.org
• Centers for Disease Control and Prevention. “Urinary Tract Infection (UTI) Guidelines.” 2023. cdc.gov
• National Institutes of Health. “Management of Complex Fistulas.” NIH Clinical Guidelines, 2022.
• World Health Organization. “Surgical Safety Checklist.” WHO, 2021.
• Cleveland Clinic. “Ureteral Injuries and Fistulas.” 2023. clevelandclinic.org
• J. Smith et al. “Outcomes of Laparoscopic Repair of Uretero‑Enteric Fistulas.” *Journal of Urology*, vol. 207, no. 4, 2022, pp. 923‑931.

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