Abstract TP256: Comparison of Predictors of Seizure in Angiogram Negative Non-Perimesencephalic Subarachnoid Hemorrhage With Aneurysmal Cases

Abstract

Background: While predictors of seizure in aneurysmal subarachnoid hemorrhage (aSAH) patients have been explored, predictors for seizure in patients with angiogram-negative non-perimesencephalic SAH (an-NPSAH) are less understood. We sought to discern the common and differentiating predictors of seizure in aSAH and an-NPSAH cohorts. Design/ Methods: We conducted a retrospective study of a prospectively collected cohort of consecutive patients admitted to an academic center between July 2016 and July 2023. Patients were categorized into aSAH or an-NPSAH based on imaging findings. Clinical data and EEG findings were retrospectively retrieved and analyzed. Binary regression analysis was used to determine the association between predictors and outcomes including clinical and electrographic seizures as indicated by periodic epileptic discharges. Results: We reviewed 473 cases (63% female) including 79 an-NPSAH and 394 aSAH. Patients in an-NPSAH group were older (mean age 61.9 years [SD 15.9] vs 56.7 [SD 13.4]). Clinical seizure at presentation or during hospital admission was seen in 8 an-NPSAH and 48 aSAH patients (10% vs 12%; p=0.6). EEG (80% spot, 20% long-term monitoring) was performed in 259 patients (55%): epileptic features were captured in 12 an-NPSAH and 52 SAH patients (15% vs. 13%; p=0.63). Both groups had similar rates of clinical and/or electrographic seizures (25.3% vs 25%; p=0.99). Predictors of seizure in aSAH were Hunt and Hess grade (OR 1.25 per grade increase, 95% CI 1.05-1.49; p=0.011); modified Fisher score (OR 1.64 per point increase, 95% CI 1.25-2.15; p<0.001) and cerebral infarct at presentation or during hospital admission (OR 3.64, 95% CI 2.13-6.23; p<0.001). Neither intracerebral hemorrhage nor aneurysm securement modality was associated with seizure. None of these factors were associated with seizure in an-NPSAH. Conclusions: Clinical or electrographic seizures are seen with similar rates in both an-NPSAH and aSAH groups. However, predictors of seizures appear to be different between these groups. Larger prospective studies are needed to identify predictors of seizure in an-NPSAH patients.