Question:medium
A 52 year old lady presents with constant leakage of urine and dysuria two weeks after a complicated total abdominal hysterectomy. A diagnosis of vesicovaginal fistula is suspected. The most important test for the diagnosis is:
A 52 year old lady presents with constant leakage of urine and dysuria two weeks after a complicated total abdominal hysterectomy. A diagnosis of vesicovaginal fistula is suspected. The most important test for the diagnosis is:
Show Hint
The bedside dye test both confirms and localises the fistula first.
Updated On: Jun 24, 2026
- Triple swab test
- Urine culture
- Cystoscopy
- Intravenous pyelography (IVP)
Show Solution
The Correct Option is A
Solution and Explanation
The leak is constant and started soon after pelvic surgery, so a fistula between the urinary tract and vagina is the working diagnosis. The first job is to prove the fistula and figure out where it opens.
The neatest bedside tool for this is the three swab dye test. You pack three swabs along the vagina from the top to the introitus, fill the bladder with a coloured dye, and then read which swab gets wet or stained. A blue stained upper or mid swab tells you the dye crossed from bladder into vagina, confirming a vesicovaginal fistula. If instead the topmost swab is soaked with clear, undyed urine, the leak is coming from above the bladder, pointing to a ureterovaginal fistula. Staining near the introitus suggests a urethral cause or stress leakage. So one cheap test confirms and localises at once.
The alternatives play supporting roles. A urine culture only addresses the dysuria and possible infection. Cystoscopy directly visualises the fistula tract and is valuable when planning surgical repair, but it is invasive and comes later. An IVP is reserved for checking the ureters when a ureteric injury is suspected. None of these is the right first diagnostic step.
$Dye\ in\ bladder + swab\ staining\ pattern \Rightarrow fistula\ confirmed\ and\ located$
\[\boxed{Triple\ swab\ test}\]
The neatest bedside tool for this is the three swab dye test. You pack three swabs along the vagina from the top to the introitus, fill the bladder with a coloured dye, and then read which swab gets wet or stained. A blue stained upper or mid swab tells you the dye crossed from bladder into vagina, confirming a vesicovaginal fistula. If instead the topmost swab is soaked with clear, undyed urine, the leak is coming from above the bladder, pointing to a ureterovaginal fistula. Staining near the introitus suggests a urethral cause or stress leakage. So one cheap test confirms and localises at once.
The alternatives play supporting roles. A urine culture only addresses the dysuria and possible infection. Cystoscopy directly visualises the fistula tract and is valuable when planning surgical repair, but it is invasive and comes later. An IVP is reserved for checking the ureters when a ureteric injury is suspected. None of these is the right first diagnostic step.
$Dye\ in\ bladder + swab\ staining\ pattern \Rightarrow fistula\ confirmed\ and\ located$
\[\boxed{Triple\ swab\ test}\]
Was this answer helpful?
0
