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How do you confirm a fistula?

What is a Fistula?

A fistula is an abnormal connection between two hollow spaces or organs that do not normally connect. Fistulas can develop in various parts of the body, but they most commonly occur between hollow organs like the bladder, urethra, intestines, rectum, vagina, blood vessels, and skin. Some common types of fistulas include:

  • Vesicovaginal fistula – between the bladder and the vagina
  • Rectovaginal fistula – between the rectum and the vagina
  • Perianal fistula – between the rectum and the skin near the anus
  • Enterocutaneous fistula – between the intestines and the skin
  • Arteriovenous fistula – between an artery and a vein

Fistulas are usually caused by injury, infection, inflammation, surgical complications or certain medical conditions like Crohn’s disease. They can lead to a host of problems including pain, infection, blockages, incontinence, malnutrition and impaired quality of life. Therefore, it’s important to diagnose and treat fistulas as soon as possible.

Signs and Symptoms of a Fistula

Some common signs and symptoms that may indicate the presence of a fistula include:

  • Discharge of pus, blood or stool from an opening in the skin or from the vagina or rectum
  • Pain and swelling around the abnormal opening
  • Foul smelling drainage
  • Irritation of the skin
  • Incontinence or leakage of urine or stool
  • Recurring urinary tract infections
  • Abdominal pain
  • Fever or chills
  • Fatigue and malaise

The specific symptoms can vary depending on the location and type of fistula. For example, a vesicovaginal fistula may cause continuous urinary incontinence while a gastrocutaneous fistula may lead to leaking of stomach contents through the skin. Paying attention to any abnormal symptoms and getting evaluated promptly is key to identifying fistulas.

Diagnosing a Fistula

If a fistula is suspected based on symptoms, the following diagnostic tests may be performed to confirm it:

  • Physical exam – The doctor will visually inspect the opening if visible on the skin and look for signs of inflammation or discharge.
  • Imaging tests – CT scans, MRI scans, ultrasound or contrast x-rays can reveal abnormal connections between organs and tissues. This helps identify the location and extent of the fistula.
  • Endoscopy – A tiny camera inserted into the affected area allows the doctor to view the fistula opening directly.
  • Fistulogram – A special dye is injected into the external opening of the suspected fistula. X-rays are then taken to track the path of the dye and highlight the internal opening and tract of the fistula.
  • Exam under anesthesia – Some fistulas like rectovaginal and vesicovaginal may require examination under anesthesia for accurate diagnosis.
  • Lab tests – Blood, urine or fluid drainage may be analyzed to check for infection or other abnormalities.

Combining information from medical history, physical examination and diagnostic tests allows clinicians to confirm the presence, location, size and complexity of fistulas. This guides appropriate treatment.

Key Steps to Confirm a Fistula

Here is an overview of the key steps involved in confirming a suspected fistula:

  1. Medical history – The patient is asked about symptoms, possible causative factors, other medical conditions, and prior surgeries or trauma.
  2. Physical exam – The suspected region is visually inspected and palpated for signs of fistula like openings, discharge, redness, swelling or tenderness.
  3. Imaging tests – CT, MRI, ultrasound or fistulograms are performed. Contrast dyemay be used to enhance visualization of abnormal tracts.
  4. Endoscopy – A tiny camera on a flexible tube is inserted into openings to directly view affected areas.
  5. Lab tests – Fluid drainage or blood samples are analyzed for signs of infection or inflammation.
  6. Examination under anesthesia – Performed if required for complicated or hard to access fistulas.
  7. Multidisciplinary input – Consult surgeons, gastroenterologists, urologists, gynecologists as needed.
  8. Develop treatment plan – Once a fistula is confirmed, appropriate treatment is planned based on its type and complexity.

Accurately diagnosing fistulas can often require a combination of different tests and specialist input. But following systematic steps allows health providers to confirm fistulas definitively.

Key Characteristics that Help Confirm Fistulas

Some of the key characteristics that help confirm the presence of a fistula include:

  • External openings – Look for small openings with granulation tissue draining pus, urine or stool on the skin or in the vagina/rectum.
  • Tracts – Fistulas have a tract or ‘tunnel’ between two structures that don’t normally connect.
  • Communication between two sites – Contrast exams or endoscopy reveals that dye/camera can travel between two separate areas or organs.
  • Inflammation – Redness, swelling, pain and discharge around external openings.
  • Recurrent infections – Persistent UTIs or vaginal infections may indicate presence of a fistula.
  • Abscess formation – Internal abscess along the fistula tract visible on imaging.
  • Symptom timeline – Sudden onset of symptoms like leakage from a new location points to a fistula.

Paying attention to these hallmark features guides both clinical and radiological assessment of potential fistulas.

Special Considerations for Complex Fistulas

Complex fistulas involving multiple tracts or openings may require additional evaluation:

  • Use of smoked incense powder or colored dyes to help delineate complex tracts during EUA.
  • Serial imaging over time to track fistula evolution.
  • 3D transperineal ultrasound to visualize peri-anal/rectovaginal fistulas.
  • MRI tractography to analyze intersections between complex tracts.
  • Temporary occlusion of tracts with glue or plugs to simplify identification.
  • Long term surgical drains or setons to prevent premature closure.

Input from colorectal, urological, gynecological and plastic surgery may be needed for large, convoluted or recurrent fistulas. Thorough evaluation allows proper planning of surgical or other interventions.

When to Seek Emergency Care

Urgent medical care should be sought if any of the following high-risk features are present:

  • Fever, chills – May indicate an infected fistula or sepsis.
  • Significant rectal bleeding – Suggests erosion into a blood vessel.
  • Extreme pain – Could mean fistula affecting a vital structure.
  • Profuse drainage – Risks dehydration, electrolyte imbalance.
  • Radiological signs of abscess – Requires urgent drainage.
  • Symptoms of bowel obstruction – Needs evaluation to rule out blockage.
  • Uncontrolled incontinence – Can lead to skin breakdown, ulceration.

Though fistulas may not resolve immediately, prompt care reduces complications. Seeking emergency help for dangerous symptoms or complications allows quicker stabilization.

When to Choose Surgery vs Conservative Treatment

Treatment decisions for fistulas depend on:

  • Cause and duration
  • Location
  • Complexity
  • Presence of underlying disease like Crohn’s
  • Impact on quality of life
Considerations for Surgery Considerations for Conservative Treatment
  • Persistent, chronic or recurrent fistulas
  • Complex tracts
  • High output fistulas
  • Significant incontinence issues
  • Severe pain or discharge
  • Failed prior conservative treatment
  • Presence of abscess
  • Small, superficial fistulas
  • No abscess
  • Mild symptoms
  • Poor surgical candidates
  • Crohn’s disease patients
  • High-risk sites like bladder, esophagus
  • Initial trial for new onset fistulas

Multidisciplinary input guides optimal management – either surgical fistula closure versus conservative measures like antibiotics, drainage, wound care and observation over time.

Diagnostic Approach Based on Symptoms

The diagnostic approach depends on the patient’s presenting symptoms:

Urinary Leakage

  • Urinalysis
  • Cystoscopy
  • Fistulogram
  • MRI pelvis
  • Assess for vesicovaginal or rectovesical fistula

Fecal Leakage

  • Colonoscopy
  • Contrast enema
  • EU exam under anesthesia
  • Endoanal ultrasound
  • Assess for rectovaginal, perianal or enterocutaneous fistula

Vaginal Discharge

  • Pelvic exam
  • Vaginal culture
  • Cystoscopy
  • Assess for vesicovaginal or rectovaginal fistula

Drainage from Skin

  • Fistulogram
  • CT scan
  • Assess for enterocutaneous fistula

Starting with least invasive tests first, then tailoring imaging and endoscopy based on likely fistula locations informed by symptoms narrows the differential diagnosis.

When Fistula Repair can be Done vs Should be Avoided

Favorable for Repair Unfavorable for Repair
  • No active inflammation
  • No distal obstruction
  • No infection
  • Good nutritional status
  • Simple tract anatomy
  • Competent anal sphincter
  • No other major medical issues
  • Active local inflammation
  • Distal obstruction not resolved
  • Ongoing sepsis
  • Malnourished
  • Complex fistula anatomy
  • Impaired continence mechanism
  • Unoptimized medical problems

Careful pre-operative optimization provides the best results.Delaying repair until any reversible risk factors are corrected allows for better wound healing and functional outcomes.


In summary, diagnosing fistulas requires a stepwise approach:

  • Thorough history and physical examination
  • Visualization with imaging like CT, MRI, ultrasound
  • Direct visualization with endoscopy and EU exam
  • Adjunct tests like fistulogram or seton placement
  • Multidisciplinary input for complex cases

Definitively confirming fistula anatomy guides appropriate surgical versus nonsurgical treatment tailored to the patient. A systematic approach is key for accurate diagnosis and optimal outcomes.