What is the most accurate statement regarding colovesical fistula?

Colovesical Fistula: Characteristics, Diagnosis, and Management

The most accurate statement regarding colovesical fistula is that it most commonly presents with pneumaturia, which occurs in approximately 90% of cases. 1

Etiology and Demographics

• Colovesical fistulas (CVFs) account for approximately 95% of all enterovesical fistulas 2
• Diverticular disease is the most common cause, accounting for approximately 72-88% of cases 2, 1, 3
• Other causes include colorectal cancer (10-15%), Crohn's disease (10%), radiation therapy, and iatrogenic injury 2, 4
• CVFs are more common in males than females due to the protective effect of the uterus and adnexa in women, which separate the sigmoid colon from the bladder 2, 3

Clinical Presentation

• Pneumaturia (air in urine) is the most common presenting symptom, occurring in 90% of cases 1
• Fecaluria (fecal material in urine) is present in approximately 40-90% of cases 2, 1
• Recurrent urinary tract infections are common, occurring in about 47% of cases 2
• Less common presentations include hematuria and rectal bleeding 5

Diagnostic Approach

• The diagnosis of colovesical fistula is primarily clinical, based on the pathognomonic symptoms of pneumaturia and fecaluria 1, 4
• CT with intravenous contrast is the most sensitive imaging modality for detecting colovesical fistulas, with a diagnostic sensitivity of 76.5% 6, 4
• Colovesical fistula can usually be diagnosed on contrast-enhanced CT based on:
  • Enhancing tract(s) with or without gas extending from colon to bladder wall
  • Associated focal bladder wall thickening
  • Presence of pneumaturia or fecaluria in clinical history 6
• CT cystography can provide additional information regarding size and location of the fistula for presurgical planning 7
• Cystoscopy has been reported to detect fistulae in approximately 46% of cases 1
• Barium enema is less sensitive for detecting the fistula (20%) but is useful for detecting strictures (71%) 1
• Colonoscopy is essential to exclude colonic malignancy as the underlying cause 1, 4

Management

• Surgical treatment is the standard of care for most patients with colovesical fistulas 2, 3
• The surgical approach typically involves:
  • Resection of the involved colonic segment with primary anastomosis
  • Closure of the bladder defect 2, 1
• Single-stage surgical approach (primary resection and anastomosis) should be preferred in most cases 2, 3
• Primary anastomosis can be achieved in approximately 92% of left-sided resections with low rates of anastomotic leak 1
• Multi-stage procedures with temporary diversion may be necessary in patients with:
  • Pelvic abscess
  • Advanced malignancy
  • Previous radiation therapy 3
• Laparoscopic and robotic approaches are feasible and safe when performed by skilled surgeons 3
• Conservative management is reserved for selected patients who are unfit for surgery 3

Common Pitfalls

• Over-investigation of patients with classic symptoms of pneumaturia and fecaluria 4
• Failure to perform colonoscopy to exclude malignancy as the underlying cause 1
• Relying solely on barium enema or contrast studies, which have lower sensitivity than CT 7
• Missing fistulas by not using appropriate contrast techniques during CT imaging 6

The evidence clearly shows that pneumaturia is the most characteristic presenting symptom of colovesical fistula, occurring in approximately 90% of cases, making this the most accurate statement among the options provided.