Can a Rectal Fistula Cause UTI?
Yes, rectal fistulas—specifically enterovesical fistulas (including colovesical and rectovesical fistulas)—can directly cause urinary tract infections and represent an important, though uncommon, etiology of recurrent UTI that must be considered in the differential diagnosis.
Mechanism and Clinical Presentation
Fistulous connections between the bowel and urinary tract create a direct pathway for enteric bacteria to enter the urinary system, leading to:
- Recurrent or persistent UTI (the most common presenting symptom, occurring in 73% of cases) 1
- Pathognomonic symptoms including fecaluria (passage of fecal matter in urine), pneumaturia (air in urine), and urine passing through the rectum 2, 3, 1
- Upper and lower urinary tract infections that are often recurrent and refractory to conventional antibiotic treatment 2, 4
High-Risk Populations to Consider
Suspect enterovesical fistula particularly in:
- Men with recurrent UTI refractory to treatment (colovesical fistula is especially common in older men) 4, 5
- Patients with diverticular disease (the most common cause of colovesical fistula) 5
- History of pelvic radiation therapy for prostate or other pelvic malignancies 3, 1
- Inflammatory bowel disease, particularly Crohn's disease with non-perianal fistulas to bladder 6, 5
- Pelvic malignancies (accounting for 36% of enterovesical fistulas) 1
- Prior pelvic surgery or instrumentation (iatrogenic injury accounts for 17% of cases) 1
Diagnostic Approach
The combination of three modalities establishes diagnosis in nearly all cases 1:
- Cystography (90% diagnostic yield) 1
- Barium enema (75% diagnostic yield) 1
- Cystoscopy (69% diagnostic yield, best investigation to confirm fistula presence) 1, 5
- CT scanning is also highly useful for diagnosis 3
Critical Clinical Pitfall
Many patients wait months for correct diagnosis because enterovesical fistula is not immediately suspected in the evaluation of recurrent UTI 4. The key is maintaining high clinical suspicion in men with prolonged UTI symptoms refractory to conventional treatments, especially those with risk factors listed above 4.
Management Implications
- Both urinary and fecal diversion are typically required for initial management 3
- Definitive surgical repair is complex and depends on etiology, prior radiation exposure, patient comorbidities, and nutritional status 3, 1
- Quality of life considerations are paramount, as even successful anatomical repair often leaves functional sequelae affecting continence and sexual function 2
Special Consideration: Radiation-Induced Fistulas
In radiation-induced rectourinary fistulas, radiation proctitis with rectal ulcer formation precedes fistula formation in most patients (6 of 7 cases) and must be aggressively managed 3. These represent particularly devastating complications with limited options for definitive repair 3.