Although they are generally considered benign and self-limited episodes, febrile seizures are usually very frightening to those who witness them, since during them, children can lose consciousness, change the color of their skin (pallor or cyanosis), present movements and contractions of the upper and lower extremities, as well as present rigidity or loss of tone of the 4 limbs (hypotonia).
And although during them there is an abrupt alteration of brain functions secondary to an abnormal neuronal discharge, they usually subside on their own without treatment. They do not necessarily lead to any other long-term health problems, and there is currently no scientific evidence that they cause brain damage. In fact, it is known that about 95-98% of children who have experienced febrile seizures will not develop subsequent epilepsy. On the other hand, population-based studies have found that children who have febrile seizures subsequently achieve normal academic achievement and perform on cognitive assessments in the same manner as siblings who do not have seizures.
When do febrile seizures occur?
As a general rule, febrile seizures occur between the ages of 6 months and 6 years, with a peak incidence at 18 months. To make the diagnosis, the possibility of acute infection of the central nervous system (meningitis-encephalitis) must be excluded, or that the seizures with fever occur in a known epileptic.
The minimum rectal temperature necessary to produce seizures is 38º C or 38.5º C for some authors, with a sudden increase in temperature being the most important triggering factor.
Twenty-one percent of febrile seizures occur in the first hour of the febrile process, 57% in the period from the first hour to 24 hours and 22% after 24 hours. Generally, it is a familial disorder, since its frequency is much higher in parents and siblings of children with febrile seizures than in the normal general population.
The infections that most frequently produce the fever that triggers seizures will logically be those that are frequently seen at this age: upper respiratory tract viral infections, otitis, urinary tract infections, pneumonia, diarrhea and less frequently bacterial infections.
Why is an EEG not indicated?
The performance of an EEG in children with febrile seizures may be a confounding factor rather than a diagnostic aid, and is therefore not indicated in the vast majority of cases. In fact, no prospective study has been able to demonstrate any relationship between the presence of paroxysmal abnormalities in children with febrile seizures and the subsequent development of epilepsy.
Although febrile seizures are often experienced by parents as a frightening time (and most parents are afraid that their child will die or suffer irreparable brain damage), they are usually harmless. And in fact, there is no evidence that they alone cause death, brain damage, epilepsy, intellectual decline, or learning problems in the medium to long term.