I have gas and stool in my urine, foul‑smelling urine, recurrent urinary tract infections and suprapubic pain—what could be causing this, how should I be evaluated, and what is the treatment?

Gas and Stool in Urine: Enterovesical Fistula

You have an enterovesical (most likely colovesical) fistula until proven otherwise, and CT of the abdomen and pelvis with IV contrast is the primary diagnostic test you need immediately. 1

Clinical Diagnosis

Your symptom constellation is pathognomonic for an enterovesical fistula:

• Pneumaturia (gas in urine) and fecaluria (stool in urine) are diagnostic hallmarks that essentially confirm a fistula between bowel and bladder 1, 2
• Foul-smelling urine, recurrent UTIs, and suprapubic pain complete the classic presentation 2, 3
• These symptoms occur because bowel contents (including gas-producing bacteria and fecal matter) are directly entering your urinary system 4

Most Common Causes

The underlying etiology determines your treatment approach:

• Diverticulitis is the most common cause of colovesical fistula, accounting for the majority of cases 1, 3
• Crohn's disease accounts for approximately 9% of enterovesical fistulas, occurring more often in men 1, 2
• Colorectal or pelvic malignancy must be excluded 1
• Other causes include radiation injury, pelvic infections, and postoperative complications 1

Diagnostic Evaluation

First-Line Imaging

CT abdomen and pelvis with IV contrast is your primary diagnostic test 1:

• CT has a diagnostic sensitivity of 76.5% for detecting the fistula and 94.1% for identifying the underlying cause 1
• CT is superior to other modalities because it simultaneously identifies the fistula tract, defines the etiology, and detects complications like abscesses 1
• Water-soluble contrast can be placed in the bowel or bladder to opacify fistulous tracts, though this is not always necessary 1

Complementary Diagnostic Procedures

Cystoscopy should be performed alongside imaging 1, 2:

• Cystoscopy has a 74% diagnostic yield for identifying the fistula opening in the bladder 1
• Direct visualization helps confirm the diagnosis and plan surgical repair 2

Colonoscopy or sigmoidoscopy is essential to:

• Identify the bowel source (sigmoid colon in diverticular disease, terminal ileum in Crohn's) 2
• Rule out malignancy through biopsy 5
• Assess disease extent 2

Alternative Imaging (When CT is Contraindicated)

MRI abdomen and pelvis is equally sensitive to CT for evaluating enterovesical fistulae 1:

• MRI provides excellent soft-tissue contrast and multiplanar imaging 1
• Particularly useful if repeat imaging is needed (radiation concerns) 1
• MRI altered surgical management in 15% of patients in one study 1

Tests with Lower Diagnostic Yield

The following have been largely supplanted but may occasionally be used 1:

• Barium enema or contrast enema: lower detection rate than CT 1
• Cystography: CT has replaced fluoroscopic cystography at most institutions 1
• Voiding cystourethrography: can demonstrate fistula but less comprehensive than CT 1

Treatment Approach

Surgical Management (Definitive Treatment)

Surgery is the definitive treatment and results in durable remission in 90% of cases 2:

• Standard procedure involves resection of the diseased bowel segment (typically sigmoidectomy for diverticular disease) with primary anastomosis 3
• The fistula tract is divided between sigmoid colon and bladder 3
• Partial cystectomy is required in only 6-8% of cases; full cystectomy or nephrectomy is almost never needed 2
• Recurrent fistulas after surgery occur in only 3-4% of patients 2

Medical Therapy (Limited Role)

Medical management alone is rarely successful 2:

• In Crohn's disease, antibiotics and/or immunosuppressants may be attempted first, but only 1 out of 4 patients achieved adequate symptom relief without surgery 2
• Antibiotic suppression can provide temporary relief but does not address the underlying structural problem 2
• Medical therapy deserves further study but should not delay definitive surgical consultation 2

Immediate Management

While awaiting definitive treatment:

• Treat active UTIs with culture-directed antibiotics 1
• Maintain adequate hydration 1
• Urinary catheterization may be needed if bladder inflammation is severe 3

Critical Pitfalls to Avoid

• Do not dismiss recurrent UTIs as simple cystitis—any patient with persistent UTI symptoms unresponsive to standard therapy should be evaluated for fistula 3
• Do not rely solely on demonstrating the fistula tract—the primary goal is identifying the underlying cause to guide appropriate therapy 3
• Do not delay surgical referral—medical therapy alone is inadequate for most enterovesical fistulas 2
• Do not assume you need to visualize the fistula tract during surgery—in some cases the tract is not directly visible but the diseased bowel segment is still resected successfully 3

Prognosis

With appropriate surgical management, outcomes are excellent 2:

• 90% of patients undergo successful surgical repair 2
• Recurrence rates are low (3-4%) 2
• Most patients are discharged within 6-10 days postoperatively 3
• Urinary catheters are typically removed 10-14 days after surgery 3