Diagnosis of epileptic syndrome after a new onset seizure and its correlation at long-term follow-up: longitudinal study of 131 patients from the emergency room

Abstract

This study aims to demonstrate the reliability of the diagnosis of epilepsy after a new onset seizure, supported by a detailed anamnesis and the complementary tests accessible at the emergency room (ER), such as CT-scan and video-EEG. It was a prospective study including 131 adult patients (55% males, medium age 52.42 (±21.5)[16-98] years-old, follow-up 25.22 (±13.69)[12-31] months). In half of cases we could not identify any predisposing factor. Within the first 72 h, patients were included into an epileptic syndrome according to the ILAE 1989 classification, if possible. Thereafter, they were followed-up in the outpatient clinic of the Epilepsy Unit, where seizure recurrence was recorded and further diagnostic examinations were performed. 94.1% of patients initially diagnosed of epilepsy were confirmed as epileptics, and up to 57% of patients could be classified into a particular syndrome from the ER. Conversely, 44.6% of patients with the initial diagnosis of isolated seizure and one third of patients with non-epileptic seizures developed recurrence, switching their initial diagnosis to epilepsy. Both CT-scan and early EEG demonstrated its usefulness evaluating the risk of recurrence after a new onset seizure (Positive predictive value 78% and 88%, respectively). Epileptiform activity was a predictor of seizure recurrence (p<0.05), independently to the moment where the EEG was performed. According to our results, it is realistic to perform the diagnosis of epilepsy after a new onset seizure, although many patients still need further specific examinations, or seizure recurrence, to be diagnosed.