Abstracts

Rationale: Intraparenchymal hemorrhage (IPH) is a common and often devastating cause of disability. Many of these patients have seizures detected on continuous EEG (cEEG) monitoring, but the specific characteristics of IPH that define seizure risk are poorly understood. Methods: A retrospective chart review of 121 patients with IPH who underwent both brain imaging (CT or MRI) and cEEG between 01/01/2013 to 12/31/2014 was conducted. Eleven patients with isolated cerebellar or brainstem hemorrhages were excluded. A total of 110 patients, with median age of 73 [IQR 83-60] years, were included in final analysis. Epileptogenic cEEG was defined as the presence of lateralized periodic discharges (LPDs), given their high independent association with seizures, and/or electrographic seizures. Subcortical IPH was defined as subcortical white matter, thalamic or basal ganglia IPH. Primary aim was to look for the incidence of electrographic seizures and epileptogenic cEEG in patients with IPH, particularly those patients with subcortical IPH. Secondary aim was to report time of EEG placement from admission and time of first seizure from EEG placement. Results: Of the 110 patients, 40 (36.4%) had subcortical IPH +/- IVH. Five (12.5%) of these 40 patients had EEG seizures. Sixty six (60%) patients from the study population had cortical IPH +/- IVH. Eleven (16.7%) of these 66 patients had seizures. [OR=0.71, CI=0.23 to 2.23, p=0.56]. Four patients had both subcortical and cortical IPH. A total of 18 (16.4% of the 110) patients had electrographic seizures. Of these 18 patients, 5 (27.8%) patients had subcortical IPH +/- IVH, 11 (61.1%) had cortical IPH +/- IVH and 2 (10.5 %) patients had both cortical and subcortical IPH. Seven (6.4%) had LPDs without seizures. This accounted for a total of 25 (22.7%) with epileptogenic cEEG. Of these 25 patients, 7(28%) patients had subcortical IPH +/- IVH. Fifteen (60%) of the 25 patients had cortical hemorrhage +/- IVH. Three patients had both cortical and subcortical IPH. Thus 17.5% of patients with subcortical IPH and 22.7% of patients with cortical IPH had epileptogenic cEEG [OR=0.55, CI=0.20 to 1.48, p=0.23]. Average time for cEEG placement from admission was 6 hours and 9 minutes. Average time from cEEG placement to first seizure was 7 hours and 4 minutes. Five patients had seizure occurrence within 1 hour and 30 minutes of cEEG placement. Conclusions: Subclortical IPH is a common etiology of IPH and often overlooked in terms of seizure risk. Our results show that a significant portion of the patients with IPH and seizures on cEEG monitoring had subcortical hemorrhages accounting for 28% of cases and for 13% of all the patients with subcortical IPHs. This suggests that all patients with supratentorial IPH should be evaluated for subclinical seizures and epileptogenicity. Specifically subcortical IPH should be evaluated for risk of seizures and placed on cEEG. Additionally, time from admission to cEEG placement should be sooner rather than later. Funding: none