S. Shinnar et al., Predictors of multiple seizures in a cohort of children prospectively followed from the time of their first unprovoked seizure, ANN NEUROL, 48(2), 2000, pp. 140-147
The objective of this study was to assess the risk of multiple recurrences
after an initial seizure recurrence in childhood. In a prospective study, 4
07 children were followed for a mean of 9.6 years from the time of their fi
rst unprovoked seizure. Data regarding each seizure recurrence were obtaine
d and analyzed using statistical methods for survival analysis. The cumulat
ive risk of a second seizure was 29%, 37%, 43%, and 46% at 1, 2, 5, and 10
years, respectively. Of the 182 children who experienced a second seizure,
131 (72%) experienced a third seizure, 105 (58%) have bad 4 or more seizure
s, and 52 (29%) have experienced 10 or more seizures, The cumulative risk o
f a third seizure was 57%, 63%, and 71% at 1, 2, and 5 years, respectively,
after the second seizure. After a third seizure, the cumulative risk of an
other seizure was 69%, 72%, and 81% at 1, 2, and 5 years, respectively, Aft
er a second seizure, factors associated with an increased risk of additiona
l recurrences included a remote symptomatic etiology (rate ratio = 1.7) and
the occurrence of a second seizure within 6 months of the first seizure (r
ate ratio = 1.7). After a second seizure, the risk of subsequent seizures w
as greater than 50% even in the lowest risk group. With the exception of et
iology, factors associated with an increased risk of multiple recurrences a
fter the initial seizure were different than those associated with multiple
recurrences after a second seizure. Factors associated with multiple recur
rent seizures may be different than those associated with an initial recurr
ence. As most patients who experience a second seizure experience further s
eizures, these data suggest that two seizures are a sufficient epidemiologi
cal criterion for the definition of epilepsy.