Intractable Diarrhea due to Enterovesical Fistula Caused by Recurrent Urinary Tract Infection with Bladder Outlet Obstruction: A Rare Clinical Presentation of "Urinary Diarrhea".

An enterovesical fistula (EVF) is an abnormal connection between the intestinal tract and urinary bladder, typically developing with symptoms of pneumaturia and fecaluria. We herein present the case of an 81-year-old man with 10-day watery diarrhea. After ineffective empiric antidiarrheal treatment, computed tomography and cystography revealed EVF and gas in the bladder lumen and within its wall. His diarrhea improved after urethral catheter placement. EVF can occasionally cause diarrhea in a delicate pressure balance between the bladder and intestine. Clinicians should be aware of this unusual condition and include "urinary diarrhea" in the differential diagnosis of diarrhea.