Can syncope cause convulsive seizures in adults?

Abstract

Convulsive epileptic seizures triggered by transient cerebral hypoperfusion 'reflex anoxic seizures' are well-described in children but are not commonly recognized in adults. We report a case series of 12 adults who presented acutely after generalized tonic-clonic seizures with a clear syncopal phase before the convulsion. We describe the aetiology, semiology and natural history of these events. Four patients (33.3%) had relevant risk factors for development of seizures/active epilepsy. Five patients (41.7%) had recurrent events prior to initial review by an epileptologist, but when anti-syncope measures were instituted there were no seizure recurrences over a median follow-up period of 34.5 (interquartile range 29.3-41.8)months. Syncope may be an under-recognized trigger for convulsive acute symptomatic seizures. Avoidance of syncope may be more effective than anti-seizure medications in preventing reflex anoxic seizures.