Estimates of seizure recurrence after a first unprovoked seizure vary from 20% to 70% within the next two to five years, although most patients will have their second seizure within a year of the first. The lower recurrence figures apply to patients who have had a generalized (as opposed to focal) attack with no past history of febrile seizures, and who present with a normal neurologic development and examination, no family history of seizures, and normal EEG and brain imaging after the first seizure. The presence of one or more of these predisposing factors progressively increases the likelihood of recurrence. Thus, consideration of AED initiation is entertained after a single seizure only if one or more of the known predictors of subsequent seizures can be documented in a given individual (Table 5.2). It is useful for patients to understand that if AED therapy is instituted and they remain seizure free for several years, they face the choice of tapering or discontinuing the drug. Thus, unless the intention is to treat the patient for a lifetime, instituting treatment after a single unprovoked seizure to prevent recurrence of another does not resolve the problem, but merely postpones it. Coupled with the fact that patients in the developing world face significantly more difficulties
BLE Risk Factors for Recurrence after a First Unprovoked Seizure*
Factors most commonly found in the most relevant studies
• History of prior febrile convulsions
• Defined etiology (abnormal imaging, remote symptomatic etiology)
• Seizure during sleep
Factors found in single or smaller number of studies
• Family history of epilepsy
• Some factors apply to specific subpopulations, such as children/adolescents, adults, or only patients with cryptogenic epilepsies.
related to cost and availability of AEDs, these considerations should strongly encourage a high threshold for initiating treatment after a single seizure in these countries.
One situation to be singled out is the risk of recurrence after a first seizure related to acute or transitional phases of neurocysticer-cosis. It has been shown that while active infection persists, the risk of seizure recurrence is high, and an AED should be maintained during this period. After resolution, usually in 6 months to a year, the risk of seizure recurrence is low, and discontinuation of the AED should be considered.
Some patients with chronic epilepsy have very infrequent seizures, a condition sometimes referred to as oligoepilepsy. When seizures occur many years apart, the risks posed by a subsequent ictal event may not warrant the cost, inconvenience, and possible adverse side effects of continuous AED treatment. Often in industrialized countries, patients and their physicians choose not to undergo treatment for seizures that occur many years apart, and there would seem to be even more justification for foregoing treatment in such patients in developing countries.
■ Coupled with the fact that patients in the developing world face significantly more difficulties related to cost and availability of AEDs, these considerations should strongly encourage a high threshold for initiating treatment after a single seizure in these countries.
■ When seizures occur many years apart, the risks posed by a subsequent ictal event may not warrant the cost, inconvenience, and possible adverse side effects of continuous AED treatment.
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