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The main symptom referred by the patient with vesicovaginal fistulas is of continuous urinary loss with no normal urination. Despite this, if the size of the fistula is small there may occur slight urinary leak associated to intermittent urination.
In general, the vesicovaginal fistulas appear precociously, but may present themselves slowly when they are decurrent from obstetric traumas or radiotherapy, even appearing several years after the provocative factor.
The VVF diagnostic can be secured only with a physical exam and an inspection of the anterior vaginal wall in the cases of great dimension fistulas. Meanwhile, in most cases it is not possible to identify the fistula immediately and additional tests are necessary. When there are any doubts as to the identification of the liquid that flows through the patient’s vagina, like urine, a simple collection of a sample might be done, if there is enough volume, and an evaluation of the levels of creatinine and electrolytes in relation to the plasmatic concentration. In case the liquid is urine the dosage of creatinine and electrolytes tends to be high in relation to the blood and in case it is other fluids (lymph, infection, etc.) these dosages were shown to be the same or lower. The test with methylene blue is useful and, if it is adequately done, confirms the vesical origin of the urine that drains through the vagina (Fig.1). This test must be done after the clinic history and a complete physical exam, including a vaginoscopy (Fig. 2). The correct form of doing this test consists of an intra-vesical infusion of a sterile dye, diluted in a saline solution, through a Foley catheter and to observe if there is no vaginal loss). If there is none, a vaginal tampon must be placed and the patient must be asked to walk for a few minutes. Afterward, the vaginal tampon is re-evaluated to identify if there is extra leaking or not from the dye to the vagina. In the cases where a vesicovaginal fistula was not ascertained and the patient complains of vaginal loss, an investigation of other urinary fistulas is imperious (Ex: urethro-vaginal fistulas).
When the vesicovaginal fistula diagnosis is confirmed a cystoscopy must be made to evaluate the size, where the fistula is in relation to the urethra, vesical capacity and the presence of foreign bodies, these aspects are important to define the conduct and therapeutic strategy.
It is advised to do a urination urethrocystography for the diagnosis of vesico urethral reflux, eventually associated to a fistula, and will need a simultaneous treatment, besides radiological documentation of the lesion and the vesical capacity of the patient3 (Fig. 3).
In all the cases of VVF the superior urinary tract must be evaluated through a excretory urography, or if necessary, through an ascending pyelography, to identify possible obstructions or ureter-vaginal fistulas (Fig. 3) which may be associated in 10 to 15% of vesicovaginal fistula cases.4
Thomas and Williams 7 showed the importance of doing a pre-operative urodynamic exam with the purpose of documenting the existence of detrusor instability and/or an intrinsic sphincterian dysfunction. Such exam is of great importance for the correction of associated disturbances, like stress urinary incontinence, it has great restrictions on fistulas of a high out put.
Some studies tried to show the efficacy of an ultra-sound in the diagnosis of vesicovaginal fistulas, but none of these was able to show its superiority in relation to the usual diagnostic tests 8,9 .
The main differential diagnostics of VVF are: abundant vaginal discharge, lymph drainage and/or blood through the vagina in the post-operative10 and other urinary fistulas, such as: ureterovaginal fistulas, urethrovaginal and vesicocutaneous.