A lady underwent vaginal hysterectomy for Carci!noma cervix. Following the surgery after her urethral catheter was removed, she complained of urinary in!continence. On examination she had normal voiding as well as continuous incontinence. Methylene blue dye was instilled in her bladder through her urethra and she was given oral Phenazopyridine dye. After some time her pads were checked and it showed yellow staining at the top most pad, while the middle or bottom pads were unstained. She is likely to have:

Ans: B. Ureterovaginal fistula(Ref Shaws 16/e p223-224, 15/e p184; William Gynue lst/e p573)Pad showing yellow staining at top poion, but not middle or bottom poions - Likely to have Ureterovaginal fistula.Interpretations of Methylene Blue 3 Swab Test:ObservationInterpretationUpper most swabs soaked with urine but unstained with dye.Clear ureter (unstained).Via fistula a reachs vagina.Uppermost cotton swab will be wet with urine.No discoloration seen - As dye is in bladder & not in ureter.Ureterovaginal fistulaUpper and lower swab remain dry but the middle swab soaked with dyeVesicovaginal fistulaThe upper two swab remain dry but lower one soaked with dyeUrethrovaginal fistula