Abstracts

Rationale: Continuous EEG (cEEG) has helped identify non-convulsive seizures (NCS) and status epilepticus (NCSE) along with lateralized periodic patterns (LPDs or PLEDs) in ICU patients with various acute symptomatic etiologies. Their presence is known to be associated with increased morbidity and mortality during hospitalization, but their implications regarding epilepsy after discharge remains unclear. This study aims to investigate the incidence of seizures post-discharge in a cohort of patients who underwent cEEG in the critical care setting.Methods: After IRB approval, we used our cEEG reporting database from year 2013 to find study population. We excluded patients with prior epilepsy history, findings restricted to isolated sharp waves, burst suppression, or generalized periodic discharges on cEEG. Three months of clinical follow up after hospital discharge were required. Patients with LPDs and/or NCSs (Epileptic group) were further divided into three sub-groups: LPDs + Seizure (NCS/NCSE), LPDs only, Seizures (NCS/NCSE) only, to explore their impact on the risk of developing epilepsy. Demographical and clinical details were extracted from medical records. Subsequent development of epilepsy was determined based on seizure documentation after discharge in clinical charts. Multivariate data analysis using JMP 9.0 (Marlow, Buckinghamshire, UK) was done to find predictors of development of epilepsy.Results: A total of 159 patients fulfilled study criteria. Table 1 shows the demographic and clinical findings of the study population. The mean follow up period was 14.9 months (+/-6.5 months). Epileptic cEEG (LPDs and/or NCSs) was present in 81 (51%) patients. Thirty two (20.1%) patients of overall cohort had seizures after discharge. Univariate analysis showed that gender or mental status did not predict the development of epilepsy. Age, etiology and cEEG findings were independently predictive of subsequent epilepsy (Table 2), which remained predictive on multivariate analysis as well. The group with epileptic changes on cEEG had 10 times increased risk of developing subsequent epilepsy compared to non-epileptic group (OR 10.7, CI 3.4-44). Further analysis of epileptic group showed that 17.1% patients in LPDs only sub-group developed epilepsy, which was significantly less than patients in ‘Seizure only’ (38.5%) or ‘LPDs + Seizure’ group (48.5%) (p = 0.02). Patients with non-epileptic cEEG findings were least likely to develop subsequent epilepsy (6.4%). Patients with strokes and tumors had statistically higher risk of developing epilepsy in epileptic cEEG group (p = 0.02, p = 0.01, respectively).Conclusions: The presence of epileptiform discharges on cEEG predicted the development of long term epilepsy after discharge. Tumors and strokes were noted as high risk etiologies in this group to develop epilepsy. The absence of epileptiform discharges on cEEG in the ICU predicted a low risk for the development of epilepsy (6.4%), while LPDs (PLEDs) denoted increased risk at 17.1% and patients with LPDs + EEG seizures had the highest risk at 48.5%.