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The decision to begin AED therapy after a first unprovoked seizure is controversial. Estimates of the likelihood of seizure recurrence range from 25% at two years to 50% at one year (in the absence of AED therapy).1-2,4-7 The decision to start AED therapy after a first seizure must therefore be individualized for each patient.
Patients at high risk for recurrent seizures should begin AED therapy.1 However, no test or prognostic tool reliably identifies these patients, and initiating therapy carries side effects and places psychological, financial, and social burdens on the patient. The prevailing clinical practice, therefore, has been watchful waiting, with a second seizure constituting proof of high risk for recurrence—and need for AED therapy. Three-quarters of patients with two or more unprovoked seizures likely will go on to have recurrent seizures.6
On the other hand, in patients believed to be at high risk for seizure recurrence, a more aggressive approach of initiating AED therapy after the first seizure is reasonable. A number of risk factors increasing risk for seizure recurrence have been identified (see Table 2, left).1,2 It is justified to initiate AED therapy if any of these factors are present, even after a single seizure. Still, it’s important to note that most people with risk factors will not benefit from AEDs, as only about 40% will have a seizure in the following two years.1
Early initiation of AED therapy might be appropriate for patients with occupations or hobbies in which seizures could be life-threatening (e.g., scuba divers, truck drivers).2
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Low-risk patients still have a roughly 20% to 30% risk of seizure recurrence within three years.1 A second seizure that occurs while driving or while engaged in any hazardous activity could lead to serious injury.
Patients should be advised of this small but inescapable risk and instructed to contact their department of motor vehicles for specific legal restrictions, which vary by state. Once three seizure-free years have passed after a patient’s initial seizure, the chance of a recurrence falls to around 10% to 20%.6-7
Back to the Case
Our 42-year-old patient with a first seizure had normal findings on examination, laboratory studies, and brain imaging. An EEG showed epileptiform discharges in a spike and wave pattern. The attending hospitalist counseled him on his elevated risk of future seizures; the patient then elected to begin AED therapy, citing a fear of losing his driving privileges. Levetiracetam was started, which he tolerated despite mild sedation.
A year later, he suffered another seizure at his home. With regular followup and titration of his AED, he remained seizure-free for the next five years.
Bottom Line
Most patients with a single unprovoked seizure can be managed with watchful waiting, counseling, and neurological followup. Initiation of AED therapy is appropriate for patients with a high risk of seizure recurrence, or for whom another seizure could pose personal or social harm. TH
Dr. Hoffman is a hospitalist at Emory University School of Medicine in Atlanta.
References
- French JA, Pedley TA. Clinical practice: Initial management of epilepsy. N Engl J Med. 2008;359:166-176.
- Krumholz A, Wiebe S, Gronseth G, et al. Practice Parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2007;69:1996-2007.
- Schachter SC. Antiepileptic drug therapy: general treatment principles and application for special patient populations. Epilepsia. 1999;40(9):S20-25.
- Hauser WA, Rich SS, Annegers JF, et al. Seizure recurrence after a first unprovoked seizure: an extended follow-up. Neurology. 1990;40:1163-1170.
- Marson A, Jacoby A, Johnson A, et al. Immediate versus deferred antiepileptic drug treatment for epilepsy and single seizures: a randomized controlled trial. Lancet. 2005;365: 2007-2013.
- Hauser WA, Rich SS, Lee JR, Annegers JF, Anderson VE. Risk of recurrent seizures after two unprovoked seizures. N Engl J Med. 1998;338:429-434.
- Berg AT. Risk of recurrence after a first unprovoked seizure. Epilepsia. 2008;49:S13-18.
- Kim LG, Johnson TL, Marson AG, et al. Prediction of risk of seizure recurrence after a single seizure and early epilepsy: further results from the MESS trial. Lancet Neurology. 2006;5(4):317-322.