Enterovesical fistula presenting as life-threatening normal anion gap metabolic acidosis

Enterovesical fistula is a rare complication of a variety of inflammatory and neoplastic diseases. It usually presents with pneumaturia, fecaluria, urinary tract infections, or irritable bladder symptoms in the setting of either diverticulitis or malignancy. For the first time, we describe a patient with an enterovesical fistula who presented with a life-threatening normal anion gap metabolic acidosis. The direction of flow through the fistula, ie, bladder to intestine, was contingent on a spastic bladder and was responsible for the atypical presentation.