What should be evaluated on ultrasound in a patient with a uterovesical fistula and hematuria after vaginoplasty and stenosis repair?

Ultrasound Evaluation of Uterovesical Fistula with Hematuria

In a patient with uterovesical fistula and cyclical hematuria following vaginoplasty complications, ultrasound should specifically evaluate for the fistulous tract between the bladder and uterus, bladder wall integrity, hydronephrosis or ureteral obstruction, and any associated pelvic fluid collections or hematomas. 1

Primary Ultrasound Findings to Document

Fistulous Tract Visualization

• Transvaginal ultrasound is the preferred modality for identifying the fistulous tract itself, demonstrating the abnormal communication between the uterine cavity and posterior bladder wall 1
• The fistula typically appears as a hypoechoic or anechoic tract connecting the two structures 1
• Color Doppler may help delineate the tract and assess for active flow through the fistula 1

Bladder Assessment

• Evaluate the posterior bladder wall for defects, irregularities, or focal thinning where the fistula communicates 1
• Assess bladder wall thickness and any inflammatory changes surrounding the fistula site 1
• Document bladder volume and any debris or blood clots within the bladder lumen 2

Upper Urinary Tract Evaluation

• Screen for hydronephrosis bilaterally, as ureteral obstruction can occur from surgical complications or inflammatory changes 3
• Assess renal parenchymal thickness and echogenicity to exclude chronic obstruction 3
• Evaluate for perinephric fluid collections or urinomas 2

Uterine and Pelvic Evaluation

• Document uterine size, position, and any hematometra (blood collection in uterine cavity) that may be causing cyclical hematuria 4
• Assess for any associated Müllerian anomalies (bicornuate uterus, cervical agenesis) that may have contributed to the initial presentation 4
• Evaluate for pelvic fluid collections, abscesses, or hematomas 1

Critical Limitations of Ultrasound in This Context

When Ultrasound is Insufficient

• Ultrasound alone cannot definitively diagnose or fully characterize uterovesical fistulas in all cases 2
• Small fistulous tracts may be missed on ultrasound, particularly if the examination is performed between episodes of hematuria 1
• CT cystography or MRI provides superior anatomic detail and should be considered when ultrasound findings are equivocal 2

Complementary Imaging Required

• Cystoscopy remains essential for direct visualization of the fistula opening in the bladder wall and to assess for active bleeding 4, 1
• MRI is particularly valuable for complex cases, especially when associated Müllerian anomalies are suspected, as it provides superior soft tissue characterization 4
• CT cystography (retrograde bladder filling with contrast) is more sensitive than ultrasound for detecting bladder injuries and fistulas 2

Additional Ultrasound Considerations

Contrast-Enhanced Ultrasound (CEUS)

• CEUS may increase diagnostic accuracy for detecting fistulous tracts and assessing vascularity, though it is not widely available 2
• CEUS is not recommended for urinary tract and collecting system injuries where CT with delayed phase is superior 2

Follow-Up Imaging

• Ultrasound can be used for serial monitoring after fistula repair to assess for resolution and exclude complications 3
• Repeat imaging should be performed if symptoms persist or worsen despite conservative management 2

Common Pitfalls to Avoid

• Do not rely solely on ultrasound for definitive diagnosis—this patient requires cystoscopy and likely CT cystography or MRI for complete evaluation 2, 4
• Do not miss bilateral hydronephrosis, which would indicate urgent need for urinary diversion 3
• Recognize that hematuria timing (cyclical vs. continuous) provides diagnostic clues—cyclical hematuria suggests menstrual blood entering the bladder through the fistula 4
• Do not catheterize the bladder if there is blood at the urethral meatus without first performing retrograde urethrography to exclude urethral injury 2