Transurethral fistulography - a useful technique in investigating recurrent undiagnosed pneumaturia

Enterovesical fistula is a well-known cause of pneumaturia. Colovesical fis tulae are seen more commonly than ileovesical fistulae in general. However, ileovesical fistulae are twice as common as colovesical fistulae in Crohn' s ilcocolitis in which their incidence varies between 2.9% and 6.6% [1]. Co lovesical fistulae in the presence of proven diverticulosis of the sigmoid colon do not pose difficulty in diagnosis. Nor do ileovesical fistulae in p atients known to have inflammatory disorder of the small bowel, namely Croh n's disease. Cystoscopic appearances further help establish the diagnosis o f an enterovesical fistula prior to laparotomy for corrective surgery. Howe ver, in the absence of an obvious small or large bowel pathology, patients with persistent long-standing pneumaturia and recurrent urinary tract infec tions refractory to medical treatment pose some difficulty in establishing the underlying pathology to account for their pneumaturia. It is useful to establish a preoperative diagnosis of enterovesical fistula and its locatio n before embarking on a major surgery to treat it. We describe an investiga tive technique which we have found useful in confirming the presence and si te of the enterovesical fistula preoperatively in these cases. Cystoscopic findings of a papillary tumour-like appearance [4] due to bullo us oedema around the fistulous opening or erythema and mucous-like substanc e along the bladder wall are some indicators pointing to the presence of an underlying enterovesical fistula in patients with pneumaturia. However, in the absence of such classical appearances but with a strong clinical suspi cion of an enterovesical fistula, transurethral endoscopic fistulography is useful in establishing a preoperative diagnosis of an enterovesical fistul a.