Fever-related seizures in children rarely fatal

NEW YORK (Reuters Health) - Although fever-related seizures can prove fatal for some children, such deaths are nonetheless extremely rare, a large study from Denmark shows.

The findings, reported in Saturday's issue of The Lancet medical journal, should be reassuring for parents, researchers say.

About 2 percent to 5 percent of children younger than 5 will suffer at least one febrile seizure -- generalized convulsions caused by elevated body temperature. But studies on the condition have been too small to estimate how many children actually die from fever-related seizures.

For the new study, Dr. Mogens Vestergaard, from Aarhus University in Denmark, and colleagues analyzed data on nearly 1.7 million children born in Denmark between 1977 and 2004. They identified 8,172 children who died during the study period, including 232 deaths among more than 55,000 children with a history of febrile seizure.

Overall, the researchers found, children who suffered a febrile seizure were nearly twice as likely as children in the general population to die during the two years following the seizure. Beyond that point, there was no increased risk.

And while the short-term risk of death was elevated, the actual number of children who died was extremely low, Vestergaard's team stresses. Over two years, they say, there would be two deaths per 1,500 children with febrile seizures, versus one death per 1,500 children in the general population.

Moreover, the study found, much depends on the type of febrile seizure.

Children who suffered a "simple" seizure -- lasting no more than 15 minutes, without recurrence in 24 hours -- had a death rate similar to children in the general population.

Instead, the risk was linked specifically to so-called complex seizures, which are longer-lasting or arise again within 24 hours; often, deaths among these children were related to pre-existing neurological abnormalities.

The findings seem to "refute, for infants and children who have simple febrile seizures, the idea of a shared cause between febrile seizures and sudden death," Dr. Maitreyi Mazumdar, from Children's Hospital Boston, writes in a related editorial.

At the same time, she adds, the results reinforce the message that children with complex seizures and neurologic abnormalities should be followed closely by their doctors.

SOURCE: Lancet August 9, 2008.