Προοπτική μελέτη πυρετικών σπασμών: προγνωστικοί παράγοντες εμφάνισης επιληψίας

Abstract

Following a first febrile seizure (FS) 2-7% of children experience a subsequent unprovoked seizure, a risk four times the risk in the general population. The increased risk for later unprovoked seizures is substantially greater among children with neurologic abnormalities present from birth than among children without such abnormalities. For most children with febrile seizures (i.e., those with simple febrile seizures), the risk of unprovoked seizure is only slightly increased. The present study was carried out during the period 2002-2005 in order to identify the prognostic factors that can lead the child with febrile seizures to epilepsy. This study is a prospective one and included 501 children with a first febrile seizure, aged from 3 months to 5 years old, who were followed for a median time of 30 months ± 8 months. According to the protocol, we gathered information about prenatal and perinatal history of each child, family history of FS and epilepsy, age at the time of the initial febrile convulsion, dates of subsequent febrile convulsions, presence or absence of focal features (including Todd’s paresis), duration of the febrile seizure and whether repeated episodes within the same febrile illness occurred, height and duration of fever prior to the seizure, cause of fever and their frequency during the follow-up period. At the time of the first FS a detailed history was received and physical, developmental and neurologic assessments were conducted by a paediatric neurologist. All children had an electroencephalographic recording (EEG) as soon as they were afebrile, after their first FS and each FS recurrence. We gathered information not only from the first febrile seizure but also from the recurrences. In our study the percentage of subsequent epilepsy in children with first FS was estimated at least 5.4%. Univariate analysis of our data showed that prognostic factors for the occurrence of epilepsy in children with febrile seizures are: family history of epilepsy (especially maternal preponderance), complex febrile seizures at the first crisis and at recurrences, focality both at the first febrile seizure and at recurrences, duration of fever less than 12 hours prior to the first febrile seizure and multiple episodes of febrile seizures (≥ 4). Multivariate analysis revealed that the most powerful prognostic factors for epilepsy after FS are: age at onset of FS older than 3 years of age, family history of epilepsy, complex FS and multiple episodes of FS (more than four). As for the recurrences of FS multivariate analysis showed that, at the first and the second recurrence of FS focality and duration of fever less than 12 hours prior to the crisis had predictive value for the outcome of epilepsy. The combined effect of the two above factors increased the risk of epilepsy about 8,5 times. For the next recurrences (third, fourth, etc) the prognostic factor that remained was only focality and its prognostic value was multiplied. Children with four recurrences of FS had the risk of developing epilepsy increased about 30 times. The types of epilepsy that were preceded by febrile seizures were: generalized tonic-clonic epilepsy, focal epilepsy (including rolandic), generalized epilepsy febrile seizure plus syndrome, petit mal and myoclonic epilepsy. The majority of the focal epilepsies had a history of focal febrile seizures. The results from our study consist a prognostic index for the occurrence of epilepsy at each child with febrile seizure. Our research will be a very useful tool, with easily available clinical data, not only for the paediatric neurologist but also for the paediatrician.

Το ποσοστό εμφάνισης επιληψίας μετά το πρώτο επεισόδιο πυρετικών σπασμών (ΠΣ) ανέρχεται σε 2-7%. Η παρούσα μελέτη διεξήχθη την περίοδο 2002-2005 με σκοπό να αναγνωρίσει τους προγνωστικούς παράγοντες που θα οδηγήσουν τα παιδί με ΠΣ σε επιληψία. Περιελήφθησαν σε προοπτική μελέτη 501 παιδιά με πρώτο επεισόδιο ΠΣ. Η πολυπαραγοντική ανάλυση έδειξε ότι οι πιο ισχυροί προγνωστικοί παράγοντες είναι: η ηλικία έναρξης ΠΣ (>3 ετών), το οικογενειακό ιστορικό επιληψίας, οι επιπλεγμένοι ΠΣ και τα πολλαπλά επεισόδια ΠΣ (περισσότερα από τέσσερα). Σε ότι αφορά τις υποτροπές των ΠΣ προγνωστική ισχύ είχαν η εστιακή σημειολογία που πολλαπλασιάζει την ισχύ της σε βάθος χρόνου και η μικρή διάρκεια του πυρετού (<12 ώρες) από το επεισόδιο για την 1η και 2η υποτροπή. Η έρευνά μας θα αποτελέσει ένα χρήσιμο εργαλείο για τον παιδίατρο με εύκολα διαθέσιμα κλινικά στοιχεία.