Urinary Fistula - Types and Etiology

Introduction:

Abnormal connections can occur in the genitourinary system and other major organs such as the gastrointestinal tract, vascular system, lymphatic system, and skin. Fistulas can develop as a result of complications following interventional radiologic treatments. They are normally divided into those that concern the upper urinary tract (kidney, ureter), the lower urinary tract (bladder, urethra), and the female reproductive tract (vagina, uterus).

In certain cases, the urethra may develop passage or connection with the rectum, perineum, bladder, and male and female genital tissues. They can be inherited or acquired. The major diagnostic methods are cystourethroscopy and voiding cystourethrography (VCUG) or urethrography.

What Are Urinary Fistulas?

A urinary fistula is an aberrant hole or connection between urinary tract organs that filters and excretes urine (kidneys, ureter tubes, bladder, urethra). Urinary fistulas are abnormal connections between a urinary tract and another adjacent organ, such as the vagina or colon. A connection in the vaginal or urinary organs is also known as vaginal fistulas.

A fistula is an opening in the bladder, vagina, or other organs that enables urine, feces, and other waste to escape where they should not. Because of the abnormal connection, feces, and urine may be expelled from the vagina.

What Are the Various Types of Fistula?

Bladder Fistulas:

1. Enterovesical Fistula: Enterovesical fistula joins the bladder with the small or large bowel.

• Etiology: Trauma and neoplasms of the gastrointestinal or genitourinary tract commonly join the bladder to the rectum, resulting in rectovesical fistulas. The most prevalent causes of colovesical fistulas are colonic cancer and diverticulitis. In addition, Crohn's disease usually leads to ileovesical fistulas. Enterovesical fistulas can also be created due to pelvic surgery, radiation therapy, foreign bodies, and infections such as tuberculosis and syphilis.

• Clinical Presentation: Patients may have recurrent cystitis, pneumaturia(air bubbles in the urine), fecaluria (appearance of fecal matter in the urine), fever, and stomach discomfort.

• Radiographic Evaluation

• Preliminary Examination: Although computed tomography scans with oral contrast are the major imaging modality, only 20 to 42 percent of fistulous tracts may be visualized. Secondary indications are more prevalent. Intravesicular air, oral or rectal contrast in the bladder, thickening of the focal wall of the bladder, neighboring wall of the bowel, and the presence of an extraluminal mass containing air are all indicators of an enterovesical fistula.

• Other Diagnostic Tests: Cystography is less sensitive than computed tomography. It has a sensitivity of 35 to 44 percent. Diagnosis can also be accomplished using a barium enema. The sensitivity is comparable to cystography but could be more precise.

2. Vesico-Vaginal Fistula: The vesicovaginal fistula connects the bladder to the vagina.

• Etiology: Vesicovaginal fistulas can be formed by surgical and obstetric problems, foreign substances, catheters, or infections such as tuberculosis or schistosomiasis. Fistulas can develop in individuals with underlying malignancy due to initial pelvic malignancies, recurring neoplasm of the cervix, vagina, and rectum, or radiation treatment. In underdeveloped nations, obstetric difficulties following childbirth are the most prevalent cause of vesicovaginal fistulas, surgical operations within the pelvis, and complications after gynecologic treatments are more common in developed nations.

• Clinical Presentation: The symptoms include watery vaginal leakage, menouria (cyclic hematuria), and perineal dermatitis (inflammation of the skin in the genital, buttock, or upper leg areas).

• Radiographic Diagnosis: Preliminary Test: Lateral view cystography or VCUG may show the fistulous tract. If the fistula tract is tiny, voiding images can be useful.

• Confirmatory Test: An unenhanced computed tomography followed by an intravenous-contrast enhanced computed tomography in the excretory phase can identify a fistulous communication between the bladder and the vagina.

• Other Tests Used: Excretory urography can be performed to rule out a concurrent ureterovaginal fistula. However, it is not sensitive.

3. Vesicouterine Fistula: The bladder is connected to the uterus through a vesicouterine fistula.

• Etiology: Vesicouterine fistula is a less prevalent condition. Common reasons include obstetric difficulties after a cesarean section, forceps extraction, and curettage for placental excision. In addition, complications with surgical operations, intrauterine device perforation, and trauma can all result in vesicouterine fistulas.

• Clinical Presentation: Occasional urine leakage from the bladder or urinary incontinence is a warning sign. Cyclic hematuria (presence of blood in the urine), amenorrhea (absence of menstruation), and urinary tract infection are other symptoms.

• Radiographic Evaluation: Traditional diagnostic procedures include cystography, hysterography, and excretory urography. Distinguishing vesicovaginal fistula from vesicouterine fistula is challenging with the help of excretory urography. In addition, contrast medium leaking into the bladder may be seen during hysterography. After hysterography, computed tomography with intravenous contrast media or computed tomography with sagittal reformation is useful. However, the outcomes of these tests need to be more conclusive.

4. Vesicocutaneous Fistula:

• Etiology: Vesicocutaneous fistulas can develop due to surgical operations, post-radiation therapy, trauma, or iatrogenic reasons. It can also develop if a suprapubic cystostomy is removed. However, it is unusual to have a spontaneous vesicocutaneous fistula.

• Radiographic Evaluation: Diagnosis is accomplished by the use of fistulography and cystography. Computed tomography is suggested if the fistulous tract is complicated or if there is a malignant tumor.

Urethral Fistulas:

1. Urethrorectal Fistula: An unnatural passage connecting the rectum or anus and the urethra (which tube through which the urine flows out to the urinary orifice). It may develop due to prostate surgery, radiation due to cancer or for other reasons.

• Etiology: It is most commonly caused in adults following prostate surgery, urethral instrumentation, or a pelvic fracture. Tuberculosis, genitourinary malignancies, and radiation treatment can all cause this fistula.

• Clinical Presentation: Meconium-stained urine is common in children. Persistent urinary tract infection, urine per rectum, fecaluria, hematuria, and infection of the seminal vesicles are symptoms in adults.

• Radiographic Evaluation: VCUG and retrograde urethrography are performed to confirm the condition. An overlying contrast medium in the urethra or rectum may conceal the fistulous tract in an anteroposterior view. As a result, a lateral image should be taken to show the narrow line of the fistulous tract. Urethrorectal fistulas that develop following radical prostatectomy are typically found at the vesicourethral anastomosis.

2. Urethrocutaneous Fistula: A urethrocutaneous fistula joins the urethra and the skin. The communication between the urethra and the perineum is the most prevalent kind of urethrocutaneous fistula.

• Etiology: Urethroperineal fistulas form due to an infection, such as a persistent uncorrected periurethral abscess or infection due to parasites. Trauma and problems following urethral or prostate gland surgery are additional reasons in adults. A congenital urethrocutaneous fistula is a rare developmental abnormality.

• Clinical Presentation: Patients typically arrive with perineal infection or urine dribbling.

• Radiographic Evaluation: The communication site can be identified using conventional radiography tests such as VCUG, retrograde urethrography, and fistulography. Computed tomography can reveal associated problems such as abscess development.

3. Urethrogenital Fistula: A urethrogenital fistula connects the urethra and the reproductive tract in men and women.

• Etiology: The most frequent urethrogenital fistula in females is the urethrovaginal fistula. It is caused by a surgical operation, an obstetric problem, pelvic trauma, a tumor, or pelvis irradiation. After a long transurethral catheter with pressure necrosis, urethrovaginal fistulas can form. Male urethrogenital fistula is unusual. This syndrome can be caused by iatrogenic factors, such as severe penile trauma or straddle damage. A congenital abnormality may be the reason for youngsters.

• Clinical Presentation: Patients with this form of fistula have persistent watery vaginal leaking.

• Radiographic Evaluation: Although vaginal speculum examination and cystourethroscopy can detect urethrovaginal fistulas, radiographic diagnosis can be made with VCUG, sonography, or delayed intravenous contrast-enhanced CT. Urethrography can reveal fistulous tracts in male patients.

Conclusion:

Fistulas are more frequent in individuals with pelvic disorders. Its etiology includes congenital problems in children, infectious processes, malignant tumors, trauma, pelvic irradiation, and complications after obstetrics and surgical interventions. The kind of fistula determines the clinical presentation. Radiographic imaging is commonly utilized for diagnosis. Excretory urography, cystography, voiding cystourethrography, urethrography, and barium enema are common conventional radiographs used in diagnosing lower urinary tract fistulas. In some circumstances, cross-sectional imaging through computed tomography is regarded as the diagnostic mode of choice. Otherwise, it is utilized to discover intra-abdominal problems or fistulas that are difficult to show using traditional methods.