A fistula is an abnormal connection that forms between two organs or vessels that do not normally connect. A bladder fistula creates a passage between the bladder and an adjacent structure, allowing urine to leak outside its normal pathway. This abnormal opening disrupts the containment and flow of urine, often resulting in discomfort and recurrent infections.
Defining Bladder Fistulas and Their Types
A bladder fistula, also known as a urinary fistula, involves the bladder, or vesico, forming a new tract to an adjacent hollow organ or the skin. The specific type of fistula is named based on the two structures that have become connected, which helps doctors identify the location of the problem and plan the appropriate course of treatment.
The most common type is the vesicovaginal fistula, an opening between the bladder and the vagina. This connection allows urine to bypass the urethra entirely and leak continuously into the vaginal vault, leading to constant wetness and irritation.
Another frequent category is the vesicoenteric fistula, which connects the bladder to a part of the intestine or colon. These are often further specified as colovesical fistulas if they involve the large intestine or enterovesical if they involve the small intestine. Less common is a vesicocutaneous fistula, where the bladder forms an opening directly to the skin.
Common Causes and Risk Factors
The primary cause of bladder fistulas in developed countries is damage from surgical procedures in the pelvic region. Gynecological surgeries, such as hysterectomy or Cesarean sections, account for the largest number of vesicovaginal fistulas. The fistula can form if the bladder tissue is unintentionally injured, or if surrounding tissue suffers a loss of blood supply, leading to tissue death.
Outside of surgery, radiation therapy administered for pelvic cancers can damage tissue, creating a risk for fistula formation. This type of damage can be delayed, sometimes appearing months or even years after the initial treatment. Inflammatory conditions also represent a significant risk, most notably Crohn’s disease, which causes chronic inflammation and ulceration in the digestive tract.
Other inflammatory conditions, such as diverticulitis, are a frequent cause of vesicoenteric fistulas, particularly colovesical fistulas. In certain regions of the world, prolonged or obstructed labor is a major cause of vesicovaginal fistulas due to pressure necrosis.
Recognizing the Signs and Symptoms
For a vesicovaginal fistula, the most distinct symptom is the involuntary and continuous leakage of urine through the vagina. This leakage is often constant, unlike stress or urge incontinence, and it can lead to chronic skin irritation, an unpleasant odor, and persistent wetness.
If the fistula connects the bladder to the bowel, symptoms reflect the mixing of intestinal and urinary contents. Patients may notice pneumaturia, which is the passage of gas or air during urination, or fecaluria. Fecaluria occurs when urine appears cloudy, muddy, or contains visible fecal matter or pus, often accompanied by a foul odor.
Many patients experience frequent or recurrent urinary tract infections (UTIs) because of the introduction of bacteria from the bowel or vagina into the sterile urinary environment. These persistent infections, along with chronic pelvic pain or abdominal discomfort, can be an indicator that an underlying fistula is present.
Diagnosis and Treatment Options
Diagnosis begins with a thorough physical examination and a review of the patient’s medical history, particularly any recent pelvic surgeries or radiation treatments. Doctors often use a dye test, such as the methylene blue test, to confirm the presence of a connection. In this procedure, blue dye is instilled into the bladder; if a swab placed in the vagina turns blue, a vesicovaginal fistula is confirmed.
Imaging studies are employed to determine the exact location and size of the fistula tract. A computed tomography (CT) scan or a cystogram (injecting contrast dye into the bladder) can show the dye leaking into the adjacent organ. Cystoscopy, where a thin, lighted tube is inserted into the urethra, is performed to visualize the bladder’s interior and assess the opening and surrounding tissue.
Treatment approaches are determined by the fistula’s size, location, and the patient’s overall health. For very small, simple fistulas, conservative management involving the continuous placement of a urinary catheter may be attempted to allow the tract to close naturally. However, the definitive treatment for bladder fistulas is surgical repair.
The goal of surgery is to excise the abnormal tract, separate the two organs, and repair the defects in the bladder and the connected organ. Surgeons work to place a layer of healthy tissue between the two repair sites to prevent the fistula from recurring. The surgical approach (abdominal, vaginal, or laparoscopic) depends heavily on the fistula’s precise location and complexity. Following a successful repair, a catheter is typically left in place for several weeks to ensure the bladder can heal completely.