Epilepsy after aneurysmal subarachnoid hemorrhage: A population-based, long-term follow-up study

The aim was to elucidate the incidence and risk factors of epilepsy after subarachnoid hemorrhage (SAH) from saccular intracranial aneurysm (sIA) in a population-based cohort.

The Kuopio sIA Database (www.uef.fi/ns) includes all unruptured and ruptured sIA cases admitted to the Kuopio University Hospital from its defined catchment population in Eastern Finland. The use of prescribed medicines, including reimbursable antiepileptic drugs, has been entered from the Finnish national registries. The cumulative incidence and independent risk factors of epilepsy and death were analyzed in 876 patients with sIA-SAH admitted from 1995 to 2007. The competing risks analysis was used to correctly estimate the probability of epilepsy, because epilepsy and death after sIA-SAH may share risk factors.

The follow-up ended at death (n = 200) or December 31, 2008; median follow-up time was 76 months. Epilepsy was diagnosed in 113 patients in a median of 8 months after sIA-SAH. Cumulative incidence of epilepsy after sIA-SAH was 8% at 1 year and 12% at 5 years. Thirty-three percent of patients with intracerebral hemorrhage (ICH) >15 cm(3) developed epilepsy. In the 876 patients with sIA-SAH, the independent risk factors for epilepsy were ICH >15 cm(3), Hunt and Hess grade III-V, and acute seizures.

Cumulative incidence of epilepsy is 12% at 5 years. Epilepsy and 12-month mortality after sIA-SAH share poor Hunt and Hess grading as an independent risk factor. Epilepsy in the 2-week survivors of sIA-SAH is predicted by signs of primary injury in the brain tissue, most notably ICH.