Febrile convulsions are considered the most common type of seizures in children aged 3 months to 5 years. The convulsions are involuntary tremors of the limbs with body toning.
They have been differentiated from other types of seizures since the mid-19th century. At that time, treatment consisted of eliminating the cause of the fever. With the introduction of the thermometer in the late 1880s, it was understood that temperature was the primary factor in causing febrile convulsions.
“Simple” febrile convulsions are characterized by short, generally generalized crises lasting up to 5 or more minutes, accompanied by high temperature.
The second form of convulsions is the “complex” form: characterized by prolonged convulsions over 15 minutes, focal crises, often with abnormal EEG readings.
The duration of the crisis varies from patient to patient. The crisis can occur at different temperatures several times during a day or a period of temperature elevation.
The peak incidence of febrile convulsions is the age group 9-18 months.
These crises are accompanied by infections, such as: tonsillitis, pharyngitis, otitis, etc.
Epidemiological studies have made a significant contribution regarding the frequency, history of the disease, and prognosis of febrile convulsions.
Almost every article states that “febrile convulsions are the most common type among children's seizures and are found in 2–5% of children.
Using different methodologies, numerous studies have shown that febrile convulsions are encountered in different percentages in children under the age of 5 years. Different incidences are observed in different countries, for example, England 2.4%, Israel 4.7%, Chile 4%, Japan 7%, Mariana Islands 14%.
The reason for this geographical discrepancy remains unexplained, but it may be related to genetic predisposition or environmental factors.
In 28 children, one will have febrile convulsions. Febrile convulsions have 3 critical elements:
Among risk factors, the most important is the presence of a history of febrile convulsions in the family. The more affected relatives, the higher the risk.
Various studies have also shown other risk factors, such as: smoking during pregnancy or the mother's respiratory infections during the first trimester of pregnancy.
Different authors have studied the risk of recurrence of febrile convulsions. About one-third of children who have had a febrile seizure will have at least one recurrence.
Data from various epidemiological studies provide figures that from 2 to 10% of children with febrile convulsions develop epilepsy. In most studies, the risk of progression to epilepsy after a single febrile crisis is not significant compared to the normal population. Even in populations with a high incidence of febrile convulsions, such as in Japan, no significant differences from populations with a lower incidence are observed. The risk factors for the progression of febrile convulsions to epilepsy are as follows:
In the case of complex febrile convulsions, the more complex manifestations, the greater the risk. Children with prolonged and focal febrile crises are particularly at high risk for epilepsy.
The more of these factors are encountered, the greater the possibility of progression to epilepsy. Two of the most important risk factors for progression to epilepsy are neurological abnormalities and family history of epilepsy. Whereas family history of febrile convulsions, age at the first febrile crisis, temperature, and gender have not been shown to increase the risk for subsequent epilepsy.
Afebrile convulsions (without fever) can start from a few months after the febrile crisis up to after 30 years, but 85% start after 4 years.
The risk that a child who has experienced febrile convulsions will have afebrile convulsions is:
Febrile convulsions may precede various forms of epilepsy, such as:
Although it is not a reliable method in predicting the prognosis of febrile convulsions, EEG as a non-invasive method remains important in verifying structural changes of the CNS, as well as a conditioned predictor in the prognosis of febrile convulsions and their progression to epilepsy.
According to the American Academy of Pediatrics, children with simple febrile convulsions do not require long-term treatment with antiepileptics.
The treatment of complex febrile convulsions with continuous therapy is highly controversial, with opinions divided into two groups.
The presence of febrile convulsions causes panic among parents. Often they are uninformed about this situation and find themselves completely unprepared to act. Feelings of fear and anxiety are created in them whenever their child presents with a fever. Therefore, the doctor should inform the parents with all the necessary information about febrile convulsions, how to prevent the crisis, actions to be taken during the crisis and certainly they should be informed about the prognosis of the disease, which in most cases is benign.