Can Hematuria Be Caused by a Colovesical Fistula?
Yes, hematuria can occur with a colovesical fistula, though it is an uncommon presentation compared to the classic triad of pneumaturia, fecaluria, and recurrent urinary tract infections.
Clinical Presentation of Colovesical Fistula
The typical presenting symptoms of colovesical fistula include:
- Pneumaturia (air in urine) - the most pathognomonic finding 1
- Fecaluria (fecal material in urine) - also pathognomonic 1
- Recurrent urinary tract infections - very common 2
- Dysuria and urinary frequency 2
- Abdominal pain 2
While hematuria is listed among possible symptoms, it occurs less frequently than the classic triad 2. However, case reports document that hematuria can indeed present as a manifestation of colovesical fistula, particularly when there is concurrent diverticular bleeding traversing the fistula tract 3.
Diagnostic Approach
When colovesical fistula is suspected based on clinical presentation:
CT imaging with appropriate contrast is the primary diagnostic modality 1, 4:
- CT with rectal or oral contrast with delayed scanning is specifically useful to detect enterovesical fistulas and infected fistulous tracts 1, 4
- CT cystography has supplanted fluoroscopic cystogram for diagnosing bladder fistulas and leaks 1, 4
- Diagnostic CT findings include: enhancing tract(s) with or without gas extending from colon to bladder wall, associated focal bladder wall thickening, and clinical history of pneumaturia or fecaluria 4
MRI is equally sensitive to CT for evaluating enterovesicular fistulae with excellent soft-tissue contrast, and should be considered when soft tissue detail is critical 1, 4.
Common Etiologies
The most common causes of colovesical fistula are 2, 3:
- Diverticulitis - the most common cause, particularly complicated diverticular disease 3
- Inflammatory bowel disease (Crohn's disease) 1, 2
- Malignancy - including colorectal cancer, bladder cancer, or rarely metastatic disease from distant sites 2
- Radiation therapy complications 2
Critical Pitfalls to Avoid
Missing the diagnosis by not using appropriate contrast techniques during CT imaging is a common pitfall 4. When colovesical fistula is suspected:
- Do not rely on non-contrast CT alone 1
- Ensure delayed imaging after contrast administration to allow opacification of fistulous tracts 1
- Consider adding rectal contrast specifically when enterovesical fistula is in the differential 1, 4
Attributing recurrent hematuria solely to simple cystitis without considering fistula in patients with risk factors (prior pelvic surgery, radiation, inflammatory bowel disease, diverticular disease) can lead to delayed diagnosis 3, 5.
Management Implications
Surgical intervention is often required given limited success with conservative management alone 3. CT cystography can provide additional information regarding size and location of the fistula for presurgical planning 4.
In patients with Crohn's disease and fistulas, the location matters for nutritional management: distal (low ileal or colonic) fistulas with low output can receive enteral nutrition, while proximal fistulas with high output require partial or exclusive parenteral nutrition 1.