Iatrogenic hyponatremic seizures after routine pelvic ultrasonic imaging.

We report the unusual case of a woman who suffered grand mal seizures in the emergency department after ingesting approximately 6 L of water in the course of preparing for a pelvic ultrasound examination. The cause appears to have been due to dilutional hyponatremia, despite normal renal function, caused by the rapid ingestion of a large volume of water. We believe the practice of encouraging patients to drink a large quantity of water to distend the bladder ought to be more precisely communicated.