Epileptic Seizure Induced by Head-Up Tilt: A Case Series Study

Epilepsy and syncope can be difficult to distinguish, with misdiagnosis resulting in unnecessary or incorrect treatment and disability. Combined tilt-table and video EEG (vEEG) testing (tilt-vEEG) is infrequently used to parse these entities even at large centers. Because of the discovery of a rare case of epileptic seizure induced by head-up tilt (HUT) (no prior cases have been published), the authors sought to verify the rarity of this phenomenon.

An observational, retrospective case series study of all combined tilt-vEEG studies performed at Stanford Health Care over a 2-year period was performed. Studies were grouped into categories: (1) abnormal tilt and normal vEEG; (2) abnormal vEEG and normal tilt; (3) abnormal vEEG and abnormal tilt; (4) normal tilt and normal vEEG, with neurologic symptoms; and (5) normal tilt and normal vEEG without neurologic symptoms.

Sixty-eight percent of patients had an abnormal study (categories A-C), with only 3% having both an abnormal tilt and an abnormal EEG (category C). Of these, one patient had a focal epileptic seizure induced by HUT. With HUT positioning, the patient stopped answering questions and vEEG showed a left temporal seizure; systolic blood pressure abruptly dropped to 89 mm Hg (64 mm Hg below baseline); heart rate did not change, but pacemaker showed increased firing (threshold: <60 bpm).

Combined tilt-table and vEEG evaluation was able to identify a previously unreported scenario-head-up tilt provocation of an epileptic seizure-and improve treatment. Combined tilt and vEEG testing should be considered for episodes that persist despite treatment to confirm proper diagnosis.