Colovesical Fistula

A colovesical fistula is an abnormal communication between colon and urinary bladder.

Sigmoid diverticular disease is the commonest cause. Colorectal malignancy, Crohn disease and previous pelvic treatment are other important causes.

The sigmoid usually communicates with the bladder dome because the two structures lie directly adjacent during pelvic inflammation.

Pneumaturia and faecaluria are highly suggestive.

Other features include recurrent polymicrobial urinary tract infection, urinary frequency, dysuria and suprapubic discomfort.

Patients may have little active abdominal pain once the fistula has matured.

CT abdomen and pelvis: define the inflamed sigmoid and its relationship to the bladder; intravesical gas without recent instrumentation strongly supports the diagnosis.

Colonoscopy is required after acute inflammation settles to exclude colorectal malignancy.

Cystoscopy is most useful when bladder malignancy is suspected, haematuria is prominent or the diagnosis remains uncertain.

Treat symptomatic urinary infection and control any active diverticular sepsis first.

Definitive treatment in a fit patient is sigmoid colectomy with colorectal anastomosis.

Separate the sigmoid from the bladder and resect the diseased colon. The bladder does not require partial cystectomy unless malignancy or substantial nonviable bladder tissue is present.

A small bladder opening that is not clearly visible after separation often requires no formal closure. A definite full thickness defect can be closed primarily.

Leave a urinary catheter postoperatively, commonly for approximately 5 to 7 days after uncomplicated repair, with longer drainage for a substantial bladder reconstruction.

Routine protective stoma is unnecessary in an uncomplicated elective case but can be used when anastomotic risk is high.

Diverticular fistula is a strong indication for elective resection.