Febrile Seizures in Children

Approximately 1 in 25 children will have at least one febrile (fever) seizure. More than one-third of these children will have at least one additional febrile seizure.

Febrile seizures are convulsions that typically occur when a child’s rectal temperature is above 102 degrees Fahrenheit. Rectal temperature is 1 degree higher than an oral temperature and one degree lower than a axillary (under the arm) temperature. In other words-- if an oral temperature reading shows 101 on the thermometer, then a rectal temp would be 102 and an axillary temp would be 100. The most accurate way to take an infants temperature is rectally.  The seizure is a response to a sudden rise in body temperature. It is the sudden spike in temperature, not how high the fever reaches, that actually causes the seizure. Because a child’s temperature can spike so suddenly, sometimes the febrile seizure is the first sign that the child is even running a temperature or sick. Febrile seizures can occur at any time during the course of a fever, but are most common within the first 24 hours of fever.

The child most commonly has some sort of viral infection or illness that causes a fever, but more serious central nervous system infections should always be ruled out. Meningitis, a life threatening inflammation of the brain and spinal cord, causes less than 0.1% of febrile seizures, but should always be considered. It is common for children to run rapidly spiking temperatures after receiving immunizations, so the immunizations can indirectly be the culprit. Children rarely have a febrile seizure before the age of six months or after the age of five.

One third of children that have a febrile seizure will have at least one additional febrile seizure. The risk factors for recurrence include: onsetbefore 18 months, shorterduration of fever before the seizure occurs, a family history of febrile seizures, and having an initial complex febrile seizure- (defined below.) Genetic and familial factors may increase susceptibility to febrile seizures, but these studies are inconclusive.

Continue to read about:

General symptoms of a febrile seizure

The difference between complex and simple febrile seizures

What to do when the child is having a febrile seizure

Treatment

Outlook for a child that has a febrile seizure