fistulas

A fistula is an abnormal passageway or tunnel that forms between two epithelial surfaces, such as organs, a body cavity, or the skin. Fistulas can be congenital or acquired and may involve the anorectal region, urinary tract, vagina, or intestines. The most common type is the perianal fistula, typically arising from infection or abscess within the anal glands. Other well-described types include vesicovaginal fistulas (between bladder and vagina), rectovaginal fistulas (between rectum and vagina), enteroenteric or enterocutaneous fistulas (between loops of intestine or between intestine and skin), and various urinary fistulas (such as ureterovaginal or vesicourethral fistulas).

Causes vary and include infection and abscess formation (especially in the anorectal region), inflammatory bowel diseases such as Crohn’s disease, trauma, radiation, surgical complications, obstetric injuries, diverticular disease, and malignancy. In Crohn’s disease, fistulas can occur spontaneously due to transmural inflammation.

Symptoms depend on the fistula type but commonly include persistent drainage or leakage from an abnormal opening, pain, swelling, recurrent infections, and sometimes incontinence or leakage of stool or urine through an abnormal route.

Diagnosis combines clinical examination with imaging and sometimes endoscopy. MRI is often preferred for anorectal fistulas; other tests may include fistulography, ultrasound, CT imaging, cystoscopy, or endoscopy to identify the tract and associated disease.

Treatment aims to control infection, close the tract, and preserve function. Medical therapy may address underlying conditions (for example, Crohn’s disease). Surgical options include seton drainage, fistulotomy, advancement flaps, LIFT procedures, fibrin glue or plugs, and, for complex or urinary/genitourinary fistulas, specialized repair by appropriate surgical teams. Prognosis varies with type and complexity, with higher recurrence in complex or Crohn’s-associated fistulas.