Physicians treating adults with an unprovoked first seizure should inform them that their seizure recurrence risk is greatest, between 21% and 45%, within the first 2 years, according to a joint guideline by the American Academy of Neurology and the American Epilepsy Society.
The guideline was based on studies of adults with an unprovoked first seizure and excluded patients with a history of more than 1 seizure at the time of presentation. It was published online April 21 by Neurology.
Unprovoked seizures were classified into 2 broad categories: a seizure of unknown etiology, or a seizure related to a preexisting brain lesion or progressive central nervous system disorder. The analysis did not include provoked seizures due to an acute symptomatic condition, such as a metabolic or toxic disturbance, cerebral trauma, or stroke.
Among other recommendations, the guideline said:
- Clinicians should tell patients that clinical factors associated with an increased risk of seizure recurrence within 2 years include a prior brain insult such as a stroke or trauma (Level A), an electroencephalogram with epileptiform abnormalities (Level A), a significant brain-imaging abnormality (Level B), or a nocturnal seizure (Level B).
- Clinicians should inform patients that although immediate anti-epileptic drug (AED) therapy, as compared with delay of treatment pending a second seizure, is likely to reduce the risk of a seizure recurrence in the 2 years subsequent to a first seizure (Level B), it may not improve quality of life (Level C).
- Clinicians should advise patients that over the longer term (more than 3 years), immediate AED treatment is unlikely to improve the prognosis for sustained seizure remission (Level B).
- Clinicians should advise patients that their risk for adverse events from AED ranges from 7% to 31% (Level B) and that these events are predominantly mild and reversible.
For adults presenting with an unprovoked first seizure, immediate AED therapy as compared with no treatment is likely to reduce absolute risk by about 35% for a seizure recurrence within the subsequent 2 years (1 Class I study, 4 Class II studies), the guideline noted. The guideline authors estimated recurrence risk from pooled data, which included studies that were not randomized or controlled. Generalized tonic-clonic convulsive seizures were the major studied seizure type, with some studies including only patients with such seizures, the authors noted.
Clinicians' recommendations on whether to start immediate AED treatment after a first seizure should be based on individualized assessments that weigh the risk of recurrence against the adverse events of AED therapy, consider educated patient preferences, and advise that immediate treatment will not improve the long-term prognosis for seizure remission but will reduce seizure risk over the subsequent 2 years, the guideline said.