This is one of the main questions that parents have – namely, what are the chances that this will happen again?
If a child has one, what is the risk of recurrence?
One seizure: 1 in 3 (33%) chance of another
2+ seizures in separate events: 1 in 2 (50%) chance of having more
In a prospective cohort Berg et al noted that the overall risk of recurrence was influenced by 4 factors: “Young age at onset, a history of febrile seizures in a first-degree relative, low degree of fever while in the emergency department, and a brief duration between the onset of fever.” They followed 136 children and noted that 31.8% had recurrent seizures – specifically 17.1% had only 1 recurrence, 8.9% had 2, and 5.8% had 3 or more. If children had all 4 of the above factors their risk of recurrence was about 70%. With none, only 20%.
Offringa et al. looked at this issue from a different angle. Five different angles – er studies to be exact in which they estimated a pooled risk. They noted that in “2496 children with 1410 episodes of recurrent seizures, 32% had one, 15% had two, and 7% had three or more recurrent seizures after a first febrile seizure.” They reported that 7% had a complex seizure. The odds of recurrent seizures was highest between the age 12-24 months. After the first seizure the risk of another was 2x higher, and after a second 2.5x greater. They also asserted that a “history of febrile or unprovoked seizures in a first-degree family member and a relatively low temperature at the time of the first seizure were also associated with an increased risk of subsequent recurrences.” Furthermore, young age (< 12 months), family history of unprovoked seizures, and the initial febrile seizure that was complex were all associated with an increased risk of subsequent complex seizures.
Oh, and one more thing to remember before we close out part 3.