New onset seizures in the elderly: aetiology and prognosis

Late onset epilepsy is increasing in incidence. These patients often have significant underlying morbidity. This retrospective study in a tertiary referral centre identified 68 patients aged 65 years or older, with new onset seizures over a four-year period. 81% of patients (n = 55) were followed up at an average of 2.7 years post diagnosis. 38% of patients had evidence of cerebrovascular disease (CT visualised focal infarction, haemorrhage or small vessel ischaemia in 32%, clinical diagnosis with normal CT brain in 6%). No patient was found to have a space-occupying lesion. Of the 55 patients followed up, 45% of these had died at a mean age of 82 years old and 1.9 years post diagnosis (range 12 hours to 5 years). Three patients died as a direct result of seizures (trauma and sepsis). 14 patients died of clearly unrelated causes. Eight patients died from underlying vascular disease or Alzheimer's dementia. Patients who died during follow-up were on average 3.4 years older at the time of diagnosis than survivors (p< 0.05). Patients with atrial fibrillation at the time of diagnosis, had increased mortality (relative risk 2.53; 95% C.I. 1.19 - 5.36), but they were older than those without atrial fibrillation. At the time of follow up, 92% of those taking anti-convulsants were maintained seizure free on anticonvulsant monotherapy.