Recurrence Risk for Children With First Seizures

From Medscape Pediatrics > Viewpoints

Redefining Outcome of First Seizures by Acute Illness

Martin ET, Kerin T, Christakis DA, et al
Pediatrics 2010;126:e1477-1484

Study Summary

Although pediatric providers are familiar with febrile seizures and the generally benign recurrence prognosis they convey, it is less clear what prognosis to offer parents of children with nonfebrile first seizures.
Despite a general sense that nonfebrile first seizures associated with illnesses (eg, afebrile gastroenteritis) have a benign prognosis relative to unprovoked seizures, few sources of data support this belief.

Martin and coworkers enrolled children with a first seizure who presented to a single large, urban, pediatric emergency department. Children were 6 months to 6 years old, had experienced a witnessed event, and were without any of the following potential causes of seizure: trauma, central nervous system infection, toxic ingestion, hypoxia, pseudo-seizures, tumors, or any neurodevelopmental condition that was associated with seizures. The data were collected from 2005 to 2008.
Children were grouped as follows: febrile seizures, nonfebrile illness seizures, and unprovoked seizures (neither illness symptoms nor fever were present). The investigators also collected demographic, health history, developmental, and clinical information from the children's families.
For the children with nonfebrile illness seizures, the investigators grouped them further into gastrointestinal (GI) and nongastrointestinal categories for analyses. Stool and serum samples were obtained from children to identify etiologies of their illnesses. Children were then followed monthly after the index seizure to discern recurrence.
The study enrolled 117 children; 67% had experienced a febrile seizure, 29% a nonfebrile illness seizure, and 4% an unprovoked seizure (5 children). While the mean age of the children was 24 months, this was heavily influenced by whether the seizure was febrile or afebrile, and the mean age of the group with first unprovoked seizure was 54 months.
In bivariate comparisons, children with nonfebrile illness seizures were much more likely to experience a repeat seizure within 24 hours than were the other 2 groups (59% in nonfebrile vs 28% in febrile and 20% in unprovoked seizures). When comparing outcomes by type of illness, children with GI illnesses (compared with non-GI illnesses) had higher rates of recurrent seizures in the first 24 hours (58% vs 27%, P < .001), but they had a lower risk for subsequent seizures after the first 24 hours. Subsequent nonfebrile seizures were most common among children with an unprovoked first seizures (40%), followed by children with nonfebrile illness seizures (14%), with none occurring in children who initially presented with febrile seizures. The investigators concluded that children whose first seizure was associated with a nonfebrile illness have a prognosis similar to those who experience febrile seizures and that GI illnesses in particular appear associated with a very low risk for recurrence.

Viewpoint

Martin and colleagues comment that GI illness-associated seizures really do seem to be a different type, and emphasize that 58% of the children with GI illness did not have fever or electrolyte disturbances that accounted for their seizure.
It is reassuring to have a defined group of children with nonfebrile first seizures whose prognosis seems to be more similar to the prognosis of those with febrile rather than unprovoked seizures, so those data have important clinical value.
The investigators emphasize the need for careful reconstruction of the medical history in the week before the seizure to identify potential GI symptoms to ensure that cases associated with GI illness are not missed.
Abstract