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Difficulty: MediumPelvic Floor Disorders and Urogynecology

A 44-year-old female presents to the physician 14 days after an uncomplicated total abdominal hysterectomy for symptomatic uterine leiomyomas. She reports a new onset of constant, clear, watery fluid leaking from her vagina that requires her to wear adult diapers. She maintains a normal sensation of bladder filling and is voiding normal volumes of urine voluntarily in the toilet. To evaluate the source of the leakage, she is given oral phenazopyridine. Two hours later, a cotton tampon is placed in the vaginal canal, and her bladder is filled with a solution of methylene blue via a transurethral catheter. The patient is asked to walk around for 20 minutes. Upon removal, the tampon shows prominent orange staining near its apex, with absolutely no blue discoloration. Which of the following is the most likely diagnosis?

  1. Ureterovaginal fistulaAnswer
  2. B
    Vesicovaginal fistula
  3. C
    Urethrovaginal fistula
  4. D
    Overflow urinary incontinence
  5. E
    Vaginal vault dehiscence with peritoneal fluid leak

Answer

Ureterovaginal fistula
The correct answer is ureterovaginal fistula. The patient's continuous vaginal leakage after a hysterectomy strongly suggests a urogenital fistula. To differentiate the anatomical source of the fistula, a double-dye test can be used. Oral phenazopyridine is excreted by the kidneys, turning all freshly produced urine orange. Methylene blue is instilled directly into the bladder via a catheter. If a patient has a vesicovaginal fistula, the blue dye from the bladder leaks directly into the vagina. If the patient has a ureterovaginal fistula, the intact bladder retains the blue dye, but the injured ureter leaks the orange urine directly into the vaginal vault. The presence of orange staining with the complete absence of blue staining definitively identifies a ureterovaginal fistula.

Step-by-Step Solution

1
Analyze the patient's postoperative clinical presentation.
The patient has continuous watery vaginal discharge 14 days after a hysterectomy but still voids normally.
Continuous leakage suggests a urogenital fistula. Normal voiding suggests that at least one ureter and the bladder are functioning and intact.
2
Interpret the underlying physiology of the double-dye test.
Oral phenazopyridine turns all renal urine orange. Methylene blue is artificially placed only inside the bladder.
This setup isolates the upper urinary tract (ureters, producing orange fluid) from the lower urinary tract (bladder, containing blue fluid).
3
Correlate the physical dye results with anatomical pathology.
The tampon is stained orange but completely lacks blue staining.
Because the blue dye did not leak, the bladder must be intact. Because the orange urine bypassed the bladder and entered the vagina, there must be a connection between the ureter and the vagina (ureterovaginal fistula).

Key Concept

Differentiating post-hysterectomy urinary fistulas using the double-dye (tampon) test.
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Topics

Pelvic Floor Disorders and Urogynecology

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