Onset seizures independently predict poor outcome after subarachnoid hemorrhage

Objective: To determine whether onset seizures after subarachnoid hemorrhag e (SAH) carry independent prognostic information and to investigate the ris k factors for late seizures after SAH. Background: Modern management of SAH , including early operation, has substantially reduced mortality. No study has adequately assessed the importance of onset seizures in a contemporary SAH cohort. Methods: The authors analyzed the records and initial CT scans of 412 consecutive patients with aneurysmal or nonaneurysmal SAH admitted t o the Royal Melbourne Hospital from 1990 to 1996. Each patient with an onse t seizure (n = 32, 7.8% of cohort) was age and sex matched to two nonseizur e patients of the same cohort. Each patient with a late seizure (n = 17, 5. 1% of cohort) was matched to five control subjects of the same cohort. Resu lts: With use of logistic regression analysis, onset seizures correlated wi th the sum score of blood on initial CT scan (OR = 1.1, p = 0.05), but ther e was no significant correlation with duration of loss of consciousness at onset, Glasgow Coma Score (GCS), presence of aneurysm, or past history of h ypertension or epilepsy. Disability 6 weeks after SAH according to the Glas gow Outcome Scale was independently predicted by initial GCS of <6 (OR = 13 .7, p < 0.01) and onset seizure (OR = 7.8, p = 0.04). Late seizures within the first 6 weeks were independently related to rebleeding (OR = 94, p < 0. 01) and onset seizures (OR = 27, p < 0.01) but not to other onset variables , development of hydrocephalus, or vasospasm. Conclusion: In this single-in stitution cohort of patients with SAH, onset seizures were an independent r isk factor for late seizures and a predictor of poor outcome.