Urinary fistulae

The development of a genitourinary fistula has profound effects on both the physical and psychological health of the woman The most common simple genitourinary fistulae are: -vesicovaginal (42 per cent) -ureterovaginal (34 per cent) -urethrovaginal (11 per cent) -vesicocervical (3 per cent)

Vesicovaginal fistulae Aetiology: The most common cause of vesicovaginal fistulae in the developed world is gynaecological surgery. The procedure with the highest incidence of post operative fistula formation is a hysterectomy.(75% of cases)

Particular risk factors include distorted anatomy, for example previous surgery, fibroids or endometriosis. Other procedures include anterior colporrhaphy,laproscopic pelvic surgery and urological surgery. Pelvic malignancy, trauma and radiotherapy. In the developing world, the most common cause remains obstetric trauma.the incidence is 1- 3/1000 deliveries

Presentation The majority present with continuous leakage of urine. This leads to discomfort and excoriation in the genital region If the fistula is small, a woman may just complain of increased vaginal discharge. The timing of presentation is variable,although the most common time to present is days following surgery.

diagnosis A large fistula is usually obvious and may easily be seen by examining the woman in the left lateral position using a simms speculum. If no fistula can be seen,useful diagnostic tests include the introduction of methylene blu into the bladder, via a urethral catheter. The blue dye may then be seen draining into the vagina.

Alternatively, Bonneys three swab test,in which three swabs are placed in the vagina prior to instilling the dye, may help to locate the site of the fistula Intravenous urogram (IVU)is not usually helpful in the diagnosis of vesicovaginal fistula but is mandatory to rule out a ureterovaginal fistula or ureteric obstruction.

When the woman is anaesthetized,it is often possible to palpate the vaginal opening of the fistula tract. The vesical opening may be seen at cystoscopy,usually on the posterior wall or at the bladder base. If the fistula is not related to surgery both vaginal and vesical openings should be biopied to exclude the possibility of malignancy.

treatment Treatment options range from simple conservative measures to more complex surgical procedures. Barrier creams may help prevent the skin becoming sore and excoriated. Advice about incontinence pads, the increased risk of urinary tract infection and the need in some cases for prophylactic antibiotics may be required

Urethrovaginal fistulae In the developed world, these occur most commonly following an anterior repair with or without a vaginal hysterectomy. They may develop as result of a urethral diverticulum or its repair or following bladder neck suspension procedures. In the developing world, the overwhelming majority are again caused by childbirth.

Symptoms vary depending on the site of fistula. With a fistula higher up in the urethra there may be continuous incontinence, a fistula nearer the bladder neck may present with stress incontinence and recurrent urinary tract infections

When the fistula is lower down may cause symptom of spraying of urine at micturition or post –micturition dribble. Treatment : surgical option and women referred to specialist centers.

In the developed world, gynaecological surgery is the most common cause, with 75% being attributable to hysterectomy. Obstetric trauma is the most common cause in the developing world. Most present between 5 and 10 days post- surgery. Presentation varies from a mild discharge with small fistulae to continuous urine loss with larger fistulae IVU is mandatory as part of the assessment because of high ureteric co –morbidity.

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