fistulaa

A fistula is an abnormal connection between two epithelial surfaces, such as hollow organs, vessels, or the skin. The word fistulaa is not standard and is likely a typographical error; the correct terms are fistula, with plural fistulas or fistulae.

Types include internal fistulas, which connect two internal structures (for example enterovesical, vesicovaginal, enteroenteric), and external fistulas, which open onto the skin (for example perianal fistula). A common example is fistula-in-ano (anal fistula). Another well-known type is the arteriovenous fistula, a surgically created connection between artery and vein used for hemodialysis.

Causes include infection and inflammation (notably Crohn's disease), surgical or traumatic injury, obstruction, radiation, and malignancy. Congenital defects can also give rise to fistulas.

Symptoms depend on location. External fistulas often discharge fluid or pus and may cause pain or odor; internal fistulas may leak contents into adjacent organs, causing urinary or fecal symptoms. An arteriovenous fistula may cause a palpable thrill, audible bruit, or high-output heart failure in some cases.

Diagnosis relies on clinical examination and imaging, such as MRI or CT with contrast, fistulography, endoscopy, or ultrasound. Management aims to control infection and inflammation, treat underlying disease, and close the fistula with medical or surgical means. Surgical options vary by type and may include seton placement, fistulotomy, advancement flap, or repair of the involved organs. Dialysis fistulas are created intentionally for long-term use.

Prognosis ranges from favorable to challenging, with risk of recurrence depending on the fistula type and underlying condition. Prevention focuses on prompt treatment of infections and stable management of diseases that predispose to fistula formation.