This plain abdominal X-rays shows an air / fluid level within the urinary bladder. The commonest cause is a
vesico-colic fistula but it is occasionally seen in diabetics with urinary tract infections due to gas forming
organisms. The commonest site of pathology causing a vesico-colic fistula is the sigmoid colon. Despite the
gastrointestinal site of pathology the presenting symptoms are usually urological. Recurrent urinary tract
infections is the commonest presentation. Less than 50% have the classic symptoms of pneumaturia (the passage of
gas per urethra) and faecaluria (visible faecal material in the urine). Rarely urine may be passed per rectum.
The commonest pathological processes causing vesico-colic fistulae are:
- Diverticular disease (~60%)
- Colonic carcinoma (~25%)
- Inflammatory bowel disease (<10%)
- Post radiotherapy necrosis - usually for cervical cancer
- Bladder cancer - rare
It can be difficult to demonstrate the fistula both radiologically and at endoscopy. Multiple investigations
may be required in order to identify the site of pathology. Further investigations to be considered are:
- Cystoscopy. This frequently shows bullous oedema but the fistula is rarely directly seen.
- Barium enema. This identifies the fistula in less than 50% of cases. The finding of barium crystals in the
urine after the investigation can help with the diagnosis.
- Cystogram. This is often less sensitive than a barium enema.
- CT scan. A recent report suggests that it has a sensitivity approaching 100%. It can allow the
demonstration of gas in the bladder and often the underlying pathological cause.
Vesico-colic fistulae are more commonly seen in men than women probably due to the mechanical protective
effect of the uterus in the later. Without surgical treatment fistulae rarely heal spontaneously even with a
defunctioning proximal colostomy. In patients with advanced malignancy surgery may be inappropriate. In those
considered fit for surgery colonic primary resection and anastomosis may be possible especially if the fistula
is small and there is no pericolic sepsis. A partial cystectomy is usually preferable to simple excision of the
fistula from the dome of the bladder. The omentum should be placed between the anastomosis and bladder repair in
order to try and prevent recurrent fistula formation. A urinary catheter should be kept in place for 10 days.
Complications related to this approach are persistent urinary tract infections (~5%) and recurrent fistulae
(~15%). In those in whom primary resection is in appropriate a Hartmann's procedure should be considered.
However over 50% of those undergoing this operation never have their stoma reversed.
Driver C P, Anderson D N, Findlay K et al. Vesico-colic fistulae in Grampian Region: presentation,
assessment, management and outcome. J R Coll Surg Edinb 1997; 42: 182-185.