Fistulas are abnormal connections or passageways between two organs or vessels that do not usually connect. Although they typically develop as a result of an injury or surgery, they can also be caused by infection or inflammation. The World Health Organization estimates that there are between 50,000 and 100,000 new cases of obstetric fistula annually, ¹ and the number of all types of fistulas is substantially higher. Fistulas can occur in many parts of the body. Some common areas that see fistula formation include²:

• An artery and a vein
• The cervix and the vagina
• The neck and the throat
• The space inside the skull and the nasal sinus
• The bowel and the vagina
• The stomach and the surface of the skin
• The uterus and the peritoneal cavity
• An artery and a vein in the lungs
• The navel and the gut
• The colon and the surface of the body

Although fistulas can occur in any of these locations, the most common site is around the anus, followed by sites affecting the genital organs.

Classification and Management of Fistulas

Fistula Risk Factors

A patient may have different risk factors depending on the site that is most likely to develop a fistula.

Obstetric Fistula

Common risk factors for obstetric fistulas include³:

• The geographic location where a woman gives birth and the presence of skilled birth attendants. Obstetric fistulas are far more prevalent in sub-Saharan Africa and Asia. Women in high-income nations are often able to have more timely and appropriate intrapartum care, thereby minimizing the risk of fistula development.⁴
• The duration of labor and the use of a partograph to obtain necessary data during labor. Fistula development is more common during prolonged and obstructed labor.
• Early marriage and young age at the time of delivery.
• Older age.
• Lack of family planning.
• Lack of prenatal and antenatal care.

Anal Fistula

Common risk factors for anal fistula include⁵:

• Previous history of anal fistula or abscess
• Crohn's disease
• Ulcerative colitis
• Diverticulitis
• Trauma
• Cancer
• Human immunodeficiency virus infection and other sexually transmitted infections
• Tuberculosis
• Radiation therapy

Fistula Diagnosis

The diagnosis of a fistula often relies most heavily on a comprehensive physical examination. A thorough inspection of the vagina and perineum should be completed. If a fistula is suspected, specific tests can be performed to help confirm the diagnosis. These include contrast tests, blue dye tests, computed tomography scans, magnetic resonance imaging, anorectal ultrasound, anorectal manometry, and colonoscopy. Some symptoms of fistula development are common for all types, such as:

• Localized pain and swelling
• Bloody or foul-smelling drainage or discharge
• Soreness and itching
• Fever or chills
• Fatigue
• Discomfort
• Nausea

Symptoms of an anal fistula may also include:

• Frequent anal abscesses
• Increased pain with bowel movements

Additional symptoms of an obstetric fistula include ⁶:

• Urine leakage from the vagina
• Irritation to the external female genital organs
• Recurrent urinary tract infections
• Leakage of gas or feces into the vagina
• Abdominal pain
• Vomiting

Additional symptoms of an arteriovenous fistula (an abnormal connection between an artery and a vein) include ⁷:

• Purple, bulging veins (similar to varicose veins)
• Swelling in the arms or legs
• Decreased blood pressure
• Heart failure

When an arteriovenous fistula occurs in the lungs, the patient may also cough up blood, have a blue tint to their skin, or have clubbing of the fingers. ⁷

Fistula Management

Good hygiene is essential in preventing and treating fistulas. This includes washing the area with water and drying it thoroughly (avoiding irritants). For fistulas in the genital or anal region, patients should avoid rubbing the area with dry toilet paper and should instead use pre-moistened, alcohol-free, unscented towelettes or wipes. Moisture barrier creams may also protect the skin from liquid or feces, and talcum powder can relieve some discomfort. Patients may also want to wear clean, loose-fitting cotton clothing.⁷

Non-invasive treatment options for fistula include the use of fibrin glue to seal the fistula, the use of a plug (usually a collagen matrix) to fill the fistula, or the placement of a catheter to drain the fistula and manage infection.⁶ The only way to resolve a fistula completely is through the surgical repair of the area. Without surgery, some fistulas can cause abscesses or infections. Before surgery, a physician may recommend taking antibiotics or infliximab to prepare the area for repair. Surgery is performed either transabdominally or laparoscopically.⁶ Surgical procedures to treat fistulas include:

• Fistulotomy: A trench is created in the fistula, thus allowing healing to occur from the inside out.
• Endorectal flap: A flap is created to expose the internal opening of the fistula, which is then stitched shut, and the flap is returned to its place.
• Ligation of the intersphincteric fistula tract: The internal part of the fistula is tied off while infected glandular tissue is removed, and the fistula is stitched at the external opening.
• Fistulectomy: The fistula is wholly removed. This procedure is rare.

Medication is also commonly prescribed to help patients manage pain pre- and post-operatively.

References

1. Tuncalp O, Tripathi V, Landry E, Stanton CK, Ahmed S. Measuring the incidence and prevalence of obstetric fistula: approaches, needs and recommendations. Bull World Health Organ. 2015;93:60-62.

2. Medline Plus. Medical encyclopedia: fistula. 2019. https://medlineplus.gov/ency/article/002365.htm. Accessed November 10, 2019.

3. Tebeu PM, Fomulu JN, Khaddaj S, de Bernis L, Delvaux T, Rochat CH. Risk factors for obstetric fistula: a clinical review. Int Urogynecol J. 2012;23:387-394.

4. World Health Organization. End fistula. Restore women’s dignity. 2019. https://www.who.int/reproductivehealth/topics/maternal_perinatal/fistul…. Accessed November 10, 2019.

5. Winchester Hospital. Health library: anal fistula. https://www.winchesterhospital.org/health-library/article?id=885932. Accessed November 6, 2019.

6. National Association for Continence. What is a fistula? https://www.nafc.org/fistula. Accessed November 6, 2019.

7. Mayo Clinic. Arteriovenous fistula. 2018. https://www.mayoclinic.org/diseases-conditions/arteriovenous-fistula/sy…. Accessed November 6, 2019.