Abstracts

Clinical and biological differences between responders and non-responders to antiepileptic drugs (AEDs) may help to explain the basis for refractory epilepsy. A total of 890 patients with newly diagnosed epilepsy attended the epilepsy clinic of the Western Infirmary, Glasgow between July 1982 and May 2001. Follow up data were available for 780 (88%). All were initially treated with monotherapy and treatment was altered depending on response and tolerability. We compared the clinical characteristics of patients with newly diagnosed epilepsy who went into remission following the first AED dose (immediate responders) with those who remained pharmacoresistant de novo (non-responders). The non-responders never gained control of their seizures for any 12-month period from onset. We identified 245 (31%) immediate responders and 276 (35%) non-responders (see table). Non-responders were more likely to have clusters of seizures [OR 9.17 (95% CI 1.17-72.18), p=0.035], a family history of epilepsy [OR 1.85 (95% CI 1.1-3.11), p=0.02], traumatic head injury [OR 3.12 (95% CI 1.72-5.64), p[lt]0.001] and psychiatric co-morbidity [OR 2.02 (95% CI 1.24-3.28), p=0.004]. Factors that did not achieve statistical significance between the groups were birth injury, febrile seizures, previous status epilepticus, neurological deficit and learning difficulties. In this longitudinal study, 31% of patients with newly diagnosed epilepsy remained seizure-free following the first dose of their first AED whereas a further 35% appeared to be refractory de novo. Clinical factors that identify early refractory epilepsy could lead to improved pharmacotherapy or prompt surgery. Comparing responders with non-responders to AEDs may provide insights into the pathophysiology of refractory epilepsy.[table1]