Complications
Defined as transient hemiparesis after a febrile seizure (usually of complex and focal type).
Neurologic consultation should be obtained, as well as electroencephalogram and magnetic resonance imaging.
Incidence higher in hospital-based compared with population-based studies.
The risk of developing nonfebrile seizures has been shown to be higher for those who have a family history of epilepsy, a preexisting neurologic abnormality (cerebral palsy), or poor condition at birth (low Apgar scores at 5 minutes).[117]
Epilepsy occurs at a rate of 2% to 6%.[118][119]
Patients with partial (focal) febrile convulsions showed a trend toward a higher risk of developing epilepsy (45%) than patients with multiple febrile seizures (21%).[120] Epilepsy is not prevented by administration of intermittent or long-term prophylactic anticonvulsant therapy for febrile seizures with epileptiform electroencephalograms.[121]
Between 9% and 35% of all first febrile seizures are complex, and it may be important to establish this at presentation because children with prolonged or multiple febrile seizures are at increased risk of developing unprovoked seizures.[6]
One prospective study of 501 children with a first febrile seizure found a 5.4% risk of occurrence of epilepsy during a 30-month follow-up period. Significant risk factors for subsequent epilepsy included a maternal family history of epilepsy, complex febrile seizure, focal febrile seizure, Todd paresis, short fever duration before febrile seizure, late onset of febrile seizure >3 years, and multiple febrile seizure recurrences. Multiple febrile seizures increased the risk of epilepsy 10 times.[119]
The decision to treat febrile seizures in an attempt to prevent recurrence should be individualized.[66]
In patients with intractable focal epilepsy, an association of mesial temporal sclerosis (MTS) is sometimes made with history of prolonged febrile seizures.
There is no evidence of any risk of hippocampal sclerosis or MTS in association with simple febrile seizures.[109]
The association between febrile seizures and temporal lobe epilepsy probably results from complex interactions between several genetic and environmental factors.[122] Clinical and molecular genetic studies suggest that the relationship between febrile seizure and later epilepsy is frequently genetic, and there are a number of syndrome-specific genes for febrile seizure.[123][124]
MTS, prolonged febrile seizures, and/or a preexisting hippocampal maldevelopment may be a cause of focal epilepsy. If causative, the prevention of complex prolonged febrile seizures is important.
A prospective magnetic resonance imaging study of 329 unselected patients with febrile seizure failed to show any hippocampal injury and concluded there may be no causal relation between febrile seizure and MTS.[6]
Duration of the febrile seizure is an important determinant of later development of epilepsy and epileptiform electroencephalogram.[7][125]
In patients with intractable focal epilepsy, an association of mesial temporal sclerosis (MTS) is sometimes made with history of prolonged febrile seizures.
Specifically, neuronal damage induced by febrile seizures has been suggested as a mechanism for the development of mesial temporal sclerosis, the pathological hallmark of temporal lobe epilepsy. However, the statistical correlation between febrile seizures and temporal lobe epilepsy does not necessarily indicate a causal relationship.[126]
If causative, the prevention of complex prolonged febrile seizures is important.
A prospective magnetic resonance imaging study of 329 unselected patients with febrile seizure failed to show any hippocampal injury and concluded there may be no causal relation between febrile seizure and MTS.[6]
Duration of the febrile seizure is an important determinant of later development of epilepsy and epileptiform electroencephalogram.[7][125]
Measures of cognition, motor ability, and adaptive behavior at 1 month after a first febrile seizure and 1 year later found no difference in performance compared with controls. Factors independent of the febrile seizure that were associated with delay in developmental milestones over time included poor socioeconomic status, TV watching, fewer books, lack of breast feeding, and a febrile seizure complex in type.[127]
Deficits in facial recognition (prosopagnosia) were linked to the size of the hippocampi when tested at 1 year after the prolonged febrile seizure.[128]
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