febrile seizure

 Febrile  seizure  convulsions
 
Definition
Classification
Simple febrile convulsions
Complex febrile convulsions
Glossary
Febrile convulsions and epilepsy
Child care
Definition

In the absence of infectious diseases affecting the central nervous system, febrile convulsions outline convulsive episodes, critical or not, typical of children between the ages of 6 months and 6 years. Convulsions during feverish illness seem to be one of the most common neurological diseases of the pediatric age.
To define itself as such, a febrile convulsion must be triggered by a condition of hyperpyrexia (fever> 38 ° C *) during an extra-cerebral pathology (at least in appearance).

* 38 ° C: approximate minimum temperature rise to which we refer to hypothesize a possible manifestation of the febrile convulsion. It is right to point out that the minimum heat increase we are discussing varies (and has changed) over time based on measurement methods, statistics and scientific societies. In the context of febrile convulsions, the value of 38 ° C expresses the minimum value of body temperature established by the American Academy of Pediatrics.

The observation of the child in the midst of a febrile seizure is often alarming and shocking for many mothers. Many women, looking at their son during a febrile convulsive crisis, can not evaluate with sufficient approximation the duration of the convulsion: in such circumstances, even a few seconds may seem minute. This parameter, as we will see during the disquisition, is essential to hypothesize the possible impairment of the child's neurological activities.
It is estimated that a percentage of 2-4% of European children is affected by a form of febrile convulsion, whose peak incidence is observed around 18 months of age. However, the overwhelming majority of febrile convulsions are harmless to the young patient, so it is very unlikely that a healthy child will report permanent injuries as a result of a similar seizure.
Let us now examine the various forms of febrile convulsions, therefore the causes, the symptoms and the therapies available.
Classification

Febrile convulsions can be distinguished in two macrogroups: simple forms and complex variants.
Simple febrile convulsions

To define themselves as "simple", febrile convulsions must depend on a generalized convulsive crisis * lasting less than 15 minutes. Generally, this variant occurs in healthy children aged 6 months to 6 years, presenting a normal psychomotor development. In such circumstances, the cause lies in hyperpyrexia (fever), NOT in a CNS affection.
Simple febrile convulsions are not repeated more than once within 24 hours of the first episode. Affected children have a normal encephalogram and may have some genetic predisposition for febrile convulsions.
Complex febrile convulsions

Complex febrile convulsions are also called "high risk", since they can degenerate into epilepsy. The seizures can be focal **, partial or lateralized ***, lasting more than 15 minutes (a single episode) or 30 minutes (repeated episodes even in 24 hours). The target of febrile seizures can also consist of children younger than 6 months or older than 6 years. The encephalogram of these patients is generally impaired (regardless of the current or imminent seizure). The majority of affected patients have a positive familiarity with epilepsy and / or neurological abnormalities.
If a second febrile seizure occurs within the 15th minute of the administration of an anticonvulsant drug (used to treat the first seizure), the patient is almost certainly affected by the "complex" variant of febrile convulsions.
We speak precisely of the state of feverish illness when the convulsion is prolonged for more than 30 minutes or is characterized by more short convulsive seizures, without the restoration of the patient's conscience. In these situations, the crises are predominantly of the "clonic" type, and tend to occur over the age of 18 months.
Among the complex forms we also mention briefly the unilateral febrile convulsions: these can last for a short time or for a long time. In the first case, it is possible that the child - generally affected by preexisting encephalopathy - may undergo a post-critical, often transitory, hemiparesis ****. For unilateral and long-lasting febrile seizures, the patient may develop hemiplegia *****, post-critical flaccid emiparesis and epilepsy.
Glossary

Terminology

    Generalized crisis *: the convulsive discharge affects both the cerebral hemispheres. This particular convulsion is characterized by the bilaterality of the motor spasms. Generalized seizures are not necessarily subject to a focal cerebro-cortical pathology.
    Focal Crisis **: typical manifestations of a distinct epileptogenic event within the cerebral cortex. Often, the manifestation of a focal crisis masks an underlying focal intracranial pathology
    Partial crisis / lateralized crisis ***: the crisis begins in a particular and circumscribed cerebral site. Often, therefore, these convulsive crises involve a precise cerebral portion of a single hemisphere
    Emiparesis ****: evident difficulty / inability to move a lateral part of the body
    Hemiplegia *****: total motor impossibility involving a half of the body, expression of a brain damage against the lateral to the disease


In addition to the classification just mentioned, febrile convulsions can also be distinguished in other sub-categories, since the distinction between simple and complex forms is not always so clear. Based on the "phenotypes", febrile convulsions are distinguished in:

Early febrile convulsions: they occur within 12 months of the child's life
    Late febrile convulsions: they start after 6 years of the child. They can persist even after 6 years
    Febrile convulsions of long duration: the spasm lasts over 15-20 minutes
    Febrile convulsions with low fever: the crisis occurs in the presence of fever of 37.5-38 ° C
    Relapsing febrile seizures: seizures occur often, at (almost) every episode of alteration of basal temperature
    Afebrile convulsions: they occur without fever
    Febrile convulsions associated with neurological diseases: seizures are caused by CNS problems

Most febrile convulsions occur in the simple variant. Complex febrile seizures occur in 20% of affected children and the status of epileptic disease in 5% of these.
Febrile convulsions and epilepsy

There is a lack of a close correlation between neonatal / pediatric convulsions and the secondary development of a true epileptic form. It is estimated that the possible transformation takes place between 25% and 56% of cases.
However, some risk factors have been identified that predispose the patient to epilepsy following a febrile convulsive event. The children of epileptic parents are more at risk of developing a form of epilepsy after a first episode of febrile convulsion. Also the presence of an early anomaly in psychomotor development could, in some way, favor the progression (in a negative sense) of the convulsive pathology.
It has also been documented how a particular correlation / concatenation of particular events can affect the degeneration of the febrile convulsion in epilepsy:

    Repeated febrile seizures that take place within 24 hours of the first convulsive episode
    Duration of convulsion greater than 15 minutes
    Focal points
    Verify transient neurological abnormalities

Child care

WHAT TO DO IF ...

    ... a child aged <18 months shows a first episode of febrile convulsions. In such situations, hospitalization is recommended. In some patients (suspected of meningitis or already being treated with antibiotics BEFORE the febrile convulsion) a lumbar puncture (rachicentesi) is required
    ... a child aged> 18 months shows a first episode of febrile convulsions. In such circumstances, hospitalization may not be necessary if the patient is stable and does not show any signs or symptoms requiring a diagnostic check. Parents must be carefully instructed on what to do.
    ... a child shows a second simple febrile convulsion (in the context of a further febrile episode). Hospitalization is not necessary. To consider, however, the possibility - however remote - of a masking of infectious diseases affecting the CNS.
    ... a child presents complex febrile convulsions: admission is necessary for the appropriate diagnostic tests.