Febrile Seizures Year 4 Paediatrics Notes OmpathStudy

Febrile Seizures Year 4 · Paediatrics Collection: 4TH YEAR ALL NOTES / PAEDS / PAEDS 4.3 / Munge / CNS -- Slide 1 Febrile Seizures Dr Rose Munge Slide 2 Febrile seizures are seizures that occur between the ages of 6 and 60 mo (peak 12-18 mo) with a temperature of 38°C (100.4°F) or higher, that are not the result of CNS infection or any metabolic imbalance, and that occur in the absence of a history of prior afebrile seizures.\nA simple febrile seizure is a primary generalized, usually tonic-clonic, attack associated with fever, lasting for a maximum of 15 min, and not recurrent within a 24-hr period.\nA complex febrile seizure is more prolonged ( 15 min), and/or is focal, and/or recurs within 24 hr.\nFebrile status epilepticus is a febrile seizure lasting longer than 30 min.\nMost patients with simple febrile seizures have a very short postictal state and usually return to their baseline normal behavior and consciousness within minutes of the seizure. Febrile infection–related (or refractory ) epilepsy (FIRES) is a very different disorder seen predominantly in older ( 5 yr) usually male children and associated with an encephalitis-like illness but without an identifiable infectious agent. Children with FIRES were previously normal but subsequently develop difficult-to-treat epilepsy. Slide 3 Between 2% and 5% of neurologically healthy infants and children experience at least one, usually simple, febrile seizure. Simple febrile seizures do not have an increased risk of mortality even though they are concerning to the parents. Complex febrile seizures may have an approximately 2-fold long-term increase in mortality rates, as compared with the general population, over the subsequent 2 yr, probably secondary to a coexisting pathology.\nThere are no long-term adverse effects of having one or more simple febrile seizures. Compared with age-matched controls, patients with febrile seizures do not have any increase in the incidence of abnormalities of behavior, scholastic performance, neurocognitive function, or attention.\nChildren who develop later epilepsy, however, might experience such difficulties. Febrile seizures recur in approximately 30% of those experiencing a first episode, in 50% after two or more episodes, and in 50% of infants younger than 1 yr of age at febrile seizure onset.\nAlthough approximately 15% of children with epilepsy have had febrile seizures, only 5% (range 1–33%, dependent on risk factors) of children who experience febrile seizures proceed to develop epilepsy later in life. Slide 4 Genetic and Other Factors Leading to Febrile Seizures The genetic contribution to the incidence of febrile seizures is manifested by a positive family history for febrile seizures in many patients.\nIn some families, the disorder is inherited as an autosomal dominant trait, and multiple single genes that cause the disorder have been identified in such families.\nHowever, in most cases the disorder appears to be polygenic, and many genes predisposing to it remain to be identified.\nGenes associated with febrile seizures include SCN1A, SCN1B, SCN9A, and CPA6. In terms of other etiologies, a dysregulation between the proinflammatory IL-1β, IL-6, and IL-8 cytokines and antiinflammatory ILR- 1A cytokines has been associated with febrile status epilepticus.\nA decreased ILR-1A/IL-8 ratio (suggestive of an overall proinflammatory state) is predictive of hippocampal abnormalities on MRI done after febrile status epilepticus. The ILR-1A/IL-8 ratio may thus prove to be a potential biomarker for identifying febrile seizure patients who may be at higher risk for developing mesial temporal lobe epilepsy later in life. Almost any type of epilepsy can be preceded by febrile seizures.\nA few epilepsy syndromes typically start with febrile seizures; these are generalized epilepsy with febrile seizures plus (GEFS+), severe myoclonic epilepsy of infancy (SMEI or Dravet syndrome ), and, in many patients, temporal lobe epilepsy secondary to mesial temporal sclerosis. GEFS+ is an autosomal dominant syndrome with a highly variable phenotype. Onset is usually in early childhood, and remission is usually in mid-childhood.\nIt is characterized by multiple febrile seizures and by several subsequent types of afebrile generalized seizures, including generalized tonic-clonic, absence, myoclonic, atonic, or myoclonic astatic seizures with variable degrees of severity. A focal febrile seizures plus epilepsy variant, in which the seizures are focal rather than generalized, has also been described. Slide 5 Dravet syndrome is the most severe of the phenotypic spectrum of febrile seizure–associated epilepsies. It constitutes a distinct entity, the onset of which is in infancy.\nIt is initially characterized by febrile and afebrile unilateral clonic seizures that recur every 1 or 2 mo. These early seizures are typically induced by fever, but they differ from the usual febrile convulsions in that they are more prolonged, more frequent, and focal