Introduction: Patients with intra-parenchymal (IPH) have seizures detected on continuous EEG (cEEG) monitoring, but data that define seizure risk in IPH patients is limited.
Methods: A retrospective chart review of 110 consecutive patients that had ICH on CT or MRI imaging and cEEG monitoring from January 2013 to December 2014 was completed. Patients with isolated cerebellar or brainstem hemorrhages were excluded. Primary aim was to examine the incidence of seizures and abnormal EEG patterns in patients with IPH, particularly those patients with deep IPH. Secondary aim was to examine time from EEG placement to first seizure
Results: Median age was 73 [IQR 83-60]. 25 (22.73%) of the 110 patients had an abnormal EEG, defined as the presence of periodic lateralized epileptiform discharges (PLEDS) and/or seizures. 40 (36.36%) had subcortical white matter or thalamic or basal ganglia IPH +/- IVH. 5 (12.5%) of these 40 patients had EEG seizures. 66 (60%) patients had cortical IPH +/- IVH. 11 (16.67%) of these 66 patients had seizures. [OR=0.71, CI=0.23 to 2.23, p=0.56]. 4 patients had both deep and cortical IPH and were excluded. A total of 18 (16.36% of the 110) patients had EEG seizures. Of these 18 patients, 5 (27.78%) patients had deep IPH +/- IVH, defined as subcortical white matter, thalamic or basal ganglia IPH. 11 (61.11%) of the 18 had cortical hemorrhage +/- IVH. 2 (10.5 %) additional patients had both cortical and deep IPH. Additionally, of the 25 patients with abnormal EEG, 7(28%) patients had deep IPH +/- IVH 15(60%) of the 25 patients had cortical hemorrhage +/- IVH. Thus 17.5% of patients with deep IPH and 22.7% of patients with cortical IPH had abnormal cEEG.[OR=0.55, CI=0.20 to 1.48, p=0.23]. Average time for EEG placement from admission was 6 hours and 9 minutes. Average time from EEG placement to first seizure was 7 hours and 4 minutes.
Discussion: Subcortical IPH is common and can lead to seizure risk. Our results show that a significant portion of the patients with IPH and seizures on cEEG monitoring had subcortical hemorrhages. They accounted for 28% of cases with seizures and abnormal EEG as well as for 13% of all the patients with subcortical ICHs. This data suggests that patients with supratentorial IPH should be evaluated for subclinical seizures.