Epileptic seizures after a first stroke: the Oxfordshire community stroke project

Abstract

Objective: To describe the immediate and long term risk of epileptic seizures after a first ever stroke. Design: Cohort study following up stroke survivors for 2 to 6.5 years; comparison with age specific incidence rates of epileptic seizures in the general population. Setting: Community based stroke register. Subjects: 675 patients with a first stroke, followed up for a minimum of 2 years. Main outcome measures: Occurrence of single and recurrent seizures. Results: 52 patients had one or more post stroke seizures; in 25 the seizures were recurrent. The 5 year actuarial risk of a post stroke seizure in survivors (excluding 19 patients with a history of epilepsy and 3 patients in whom the seizure occurred shortly before death from another cause) was 11.5% (95% confidence interval 4.8% to 18.2%). The relative risk of seizures, in comparison with the general population, was estimated at 35.2 in the first year after stroke and 19.0 in year 2. The risk of seizures was increased in survivors of subarachnoid and intracerebral haemorrhage (hazard ratio for intracranial haemorrhage v cerebral infarction 10.2 (3.7 to 27.9)). The risk of seizures after ischaemic stroke was substantial only in patients presenting with severe strokes due to total anterior circulation infarction. Only 9 of 295 patients (3%) independent one month after stroke suffered a seizure between 1 month and 5 years (actuarial risk 4.2% (0.1% to 8.3%)). Conclusion: Stroke patients have about an 11.5% risk of single or recurrent seizures in the first 5 years after a stroke. Patients with more severe strokes or haemorrhagic strokes are at higher risk. Key messages: Cerebrovascular disease is an important cause of epilepsy but the risk of seizures after stroke may be overestimated by hospital based studies From a community based register, patients with a first ever stroke had a 2% risk of having a seizure at stroke onset and an 11% risk of having a later seizure in the first 5 years of follow up Patients with intracerebral and subarachnoid haemorrhage were at higher risk of seizures after stroke Survivors who were independent at 1 month were at very low risk of future seizures