The vast majority of febrile seizures are harmless. There is no evidence that febrile seizures cause brain damage.

But ... A history of the cause of fever (eg, viral illnesses, gastroenteritis) should be established. Recent antibiotic use is particularly important because partially treated meningitis must be considered. A history of seizures, neurologic problems, developmental delay, or other potential causes of seizure (eg, trauma, ingestion) should be taken.

In the US between 2% and 5% of kids will have febrile seizures before their fifth birthday. The numbers are about the same for Western Europe. As many of us have kids from other places, it's important to know that the incidence elsewhere in the world varies between 5 and 10% for India, 8.8% for Japan, 14% for Guam, 0.35% for Hong Kong, and 0.5-1.5% for China. (Some of these numbers may reflect recording processes rather than real numbers of kids and convulsions, and I can find no numbers for Africa.)

There is a genetic factor in the tendency, not that that gives us adoptive parents much of a clue, but for sibling groups it can be a real predictor. In a child with febrile seizure, the risk of febrile seizure is 10% for the sibling and almost 50% for the sibling if a parent has febrile seizures as well.

Here are the things to look for ... of course, much of this information is not available to us as adoptive parents ...

Risk factors for developing febrile seizures
Family history of febrile seizures
High temperature
Parental report of developmental delay
Neonatal discharge at an age greater than 28 days (suggesting perinatal illness requiring hospitalization)
Daycare attendance
Presence of 2 of these risk factors increases the probability of a first febrile seizure to about 30%.
Maternal alcohol intake and smoking during pregnancy has a 2-fold increased risk.

And if your kid has had one already, here are some indicators that another could occur:

About one third of all children with a first febrile seizure experience recurrent seizures.
Risk factors for recurrent febrile seizures include the following:
Young age at time of first febrile seizure
Relatively low fever at time of first seizure
Family history of a febrile seizure in a first degree relative
Brief duration between fever onset and initial seizure
Patients with all 4 risk factors have greater than 70% chance of recurrence. Patients with no risk factors have less than a 20% chance of recurrence.

Yep, if a kid has one seizure with fever, they have a 30% chance of having another. After two, the odds go up even more until they age out of the condition.

That's an important thing to remember ... they do age out. Febrile seizures, although not fully understood, appear to be the result of an immature nervous system, something that usually takes care of itself as the child grows. I had one doctor explain them to me as the equivalent of an adult having nightmares when suffering from a high fever.