Page 75 - ILAE_Lectures_2015

Chapter 8

Febrile convulsions  a practical guide

CHRISTOPHER M. VERITY

Child Development Centre, Addenbrooke’s Hospital, Cambridge

Introduction

Febrile convulsions present the most common problem in paediatric neurology. How serious
are they for the child? Opinions have changed with time. In 1949 Lennox wrote: ‘febrile
convulsions may cause brain pathology as evidenced by transient or permanent neurological
deficit’. In contrast, in 1991 Robinson referred to children with febrile convulsions as having
a ‘generally excellent prognosis’1.

Why has there been this change in opinion? One reason is that earlier reports of the relatively
poor prognosis of children with more severe problems attending specialised clinics or
hospital have been balanced by the more optimistic findings of population-based studies of
less selected groups of children2-16. Another reason is that the results of studies depend on the
way febrile convulsions are defined  some researchers have included children with
underlying meningitis or encephalitis in their studies of febrile convulsions. The issues have
been discussed in recent reviews17-20.

It is now recognised that in a small number of children febrile convulsions are the first sign
that the child has an inherited seizure disorder that includes afebrile as well as febrile seizures.

Definitions

In this text febrile convulsion is used synonymously with febrile seizure.

Febrile convulsions
It has become generally accepted that seizures known to be symptomatic of an underlying
infection should not be called febrile convulsions. The Commission on Epidemiology and
Prognosis of the International League Against Epilepsy21 defined a febrile convulsion as:

‘an epileptic seizure ... occurring in childhood after age one month, associated with a febrile
illness not caused by an infection of the CNS, without previous neonatal seizures or a
previous unprovoked seizure, and not meeting criteria for other acute symptomatic seizures’.

Simple versus complex febrile convulsions
Febrile convulsions can be sub-classified. In the National Collaborative Perinatal Project
(NCPP), the large American prospective population study9, complex febrile convulsions
(seizures) were defined as those that had one or more of the following:

 Duration more than 15 minutes
 Recurrence within 24 hours
 Focal features.