The latency of post-stroke epilepsy can predict drug resistance

Background and purpose: The progressive nature of epileptogenesis raises the question of whether the latent period may already carry information about the characteristics of the subsequent epilepsy. This study aimed to explore whether the time from stroke to epilepsy onset was related to the risk of drug resistance in patients with post-stroke epilepsy (PSE). Methods: Patients with epilepsy secondary to cerebral infarct or spontaneous intracerebral hemorrhage were included. Study outcome was the occurrence of drug resistance defined as failure of adequate trials of two tolerated and appropriately chosen and used antiseizure medication schedules to achieve sustained seizure freedom. Results: One-hundred and fifty-nine patients with PSE and a median follow-up of 5 [interquartile range (IQR) 3-9] years were included. In the study cohort, 29 (18.2%) participants were drug resistant. The median length of the time interval between stroke and PSE onset was 13 [IQR 7-15] months in drug resistant patients and 19 [IQR 14-42] months (p<0.001) in patients with seizure control. According to multivariable regression analysis, the time from stroke to PSE was an independent predictor of drug resistance (p<0.001). The risk of drug resistance was highest when the onset of PSE occurred within the first months from stroke and decreased progressively with a steeper decline over the first 12 months. Conclusions: Substantial variability may exist in the pathways leading to PSE and distinguish patients with a variable risk of drug resistance.