Fistula - Causes

Various causes of fistula are:

Causes
Category	Elaboration
Diseases	Inflammatory bowel disease in the form of Crohn's disease, but not ulcerative colitis, are the leading causes of anorectal, enteroenteral, and enterocutaneous fistulas. A person with severe stage-3 hidradenitis suppurativa will also develop fistulas.
Medical treatment	Complications from gallbladder surgery can lead to biliary fistula. Radiation therapy can lead to vesicovaginal fistula. An arteriovenous fistula can be deliberately created, as described below in therapeutic use.
Trauma	Head trauma can lead to perilymph fistulas, whereas trauma to other parts of the body can cause arteriovenous fistulas. Obstructed labor can lead to vesicovaginal and rectovaginal fistulas. An obstetric fistula develops when blood supply to the tissues of the vagina and the bladder (and/or rectum) is cut off during prolonged obstructed labor. The tissues die and a hole forms through which urine and/or feces pass uncontrollably. Vesicovaginal and rectovaginal fistulas may also be caused by rape, in particular gang rape, and rape with foreign objects, as evidenced by the abnormally high number of women in conflict areas who have suffered fistulae. In 2003, thousands of women in eastern Congo presented themselves for treatment of traumatic fistula caused by systematic, violent gang rape that occurred during the country's five years of war. So many cases have been reported that the destruction of the vagina is considered a war injury and recorded by doctors as a crime of combat.