Micturition syncope.

Micturition syncope is a poorly understood neurophysiological event. Increased vagal stimulation at night, vagal sensory input from the bladder during micturition and standing position during voiding represent the most common triggering factors of this syndrome. Postural hypotension, caused by standing during micturition, may explain the predominance of male victims. Two cases are reported--a classic male example and an unusual incident in a woman.