Aetiology

Diverticular disease is the most common cause, responsible for approximately 88% of cases. (1)

Other causes include:

• carcinoma of the bladder invading the colon
• carcinoma of the colon invading the bladder
• Crohn's disease - the incidence of enterovesical fistula among patients with Crohn's disease ranges from 2% to 5%. (2)
• radiation bowel injury. The interval between radiation therapy and fistula development typically ranges from 20 months to several years, most commonly following treatment for gynaecological or urological malignancies. (3)
• external trauma
• foreign bodies

Reference

1. Zizzo M et al. Management of colovesical fistula: a systematic review. Minerva Urol Nephrol. 2022 Aug;74(4):400-408.
2. Su YR et al. Surgical management in enterovesical fistula in Crohn disease at a single medical center. Int Surg. 2014 Mar-Apr;99(2):120-5
3. Hokama A et al. Radiation Ileitis Leading to Enterovesical Fistula. Chonnam Med J. 2022 May;58(2):77-78.