Seizures and epilepsy in children: Classification, etiology, and clinical features
- Angus Wilfong, MD
Angus Wilfong, MD
- Chief of Neurology
- Barrow Neurologic Institute at Phoenix Children's Hospital
Children with epilepsy, particularly infants, differ from adults not only in the clinical manifestations of their seizures, but also in the presence of unique electroencephalogram (EEG) patterns, etiologies, and response to antiseizure drugs. The immature brain, particularly in the neonate and young infant, differs from the adult brain in the basic mechanisms of epileptogenesis and propagation of seizures. It is more prone to seizures, but seizures are more apt to disappear as the child grows.
This topic provides an overview of the classification and etiology of seizures and epilepsy in children. The clinical diagnosis and management of new-onset seizures and epilepsy in children are presented separately. (See "Clinical and laboratory diagnosis of seizures in infants and children" and "Seizures and epilepsy in children: Initial treatment and monitoring".)
Seizure — A seizure represents the clinical expression of abnormal, excessive, synchronous discharges of neurons residing primarily in the cerebral cortex. This abnormal paroxysmal activity is intermittent and usually self-limited, lasting seconds to a few minutes.
On electroencephalography, a seizure ictus is characterized by sustained, abnormal electrical activity that has a relatively discrete beginning and end, and goes through an evolution characterized by changing morphology and amplitude (voltage) of the abnormal discharges. A focal seizure has a restricted regional onset followed by spread to neighboring or remote brain regions. It may spread to deep subcortical regions and evolve to a bilateral convulsive seizure (previously referred to as a secondarily generalized seizure, to differentiate it from seizures that are generalized from the onset) . (See "Electroencephalography (EEG) in the diagnosis of seizures and epilepsy".)
When the seizure is prolonged or immediately recurrent without a return of consciousness, this is status epilepticus. (See "Clinical features and complications of status epilepticus in children" and "Management of convulsive status epilepticus in children".)
- Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005-2009. Epilepsia 2010; 51:676.
- Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia 2014; 55:475.
- Proposal for revised clinical and electroencephalographic classification of epileptic seizures. From the Commission on Classification and Terminology of the International League Against Epilepsy. Epilepsia 1981; 22:489.
- Proposal for revised classification of epilepsies and epileptic syndromes. Commission on Classification and Terminology of the International League Against Epilepsy. Epilepsia 1989; 30:389.
- Korff C, Nordli DR Jr. Do generalized tonic-clonic seizures in infancy exist? Neurology 2005; 65:1750.
- Wyllie E. Developmental aspects of seizure semiology: problems in identifying localized-onset seizures in infants and children. Epilepsia 1995; 36:1170.
- Acharya JN, Wyllie E, Lüders HO, et al. Seizure symptomatology in infants with localization-related epilepsy. Neurology 1997; 48:189.
- Nordli DR Jr, Bazil CW, Scheuer ML, Pedley TA. Recognition and classification of seizures in infants. Epilepsia 1997; 38:553.
- Hauser WA, Annegers JF, Kurland LT. Prevalence of epilepsy in Rochester, Minnesota: 1940-1980. Epilepsia 1991; 32:429.
- Oka E, Ohtsuka Y, Yoshinaga H, et al. Prevalence of childhood epilepsy and distribution of epileptic syndromes: a population-based survey in Okayama, Japan. Epilepsia 2006; 47:626.
- Russ SA, Larson K, Halfon N. A national profile of childhood epilepsy and seizure disorder. Pediatrics 2012; 129:256.
- Murphy CC, Trevathan E, Yeargin-Allsopp M. Prevalence of epilepsy and epileptic seizures in 10-year-old children: results from the Metropolitan Atlanta Developmental Disabilities Study. Epilepsia 1995; 36:866.
- Annegers JF, Hauser WA, Lee JR, Rocca WA. Incidence of acute symptomatic seizures in Rochester, Minnesota, 1935-1984. Epilepsia 1995; 36:327.
- Rwiza HT, Kilonzo GP, Haule J, et al. Prevalence and incidence of epilepsy in Ulanga, a rural Tanzanian district: a community-based study. Epilepsia 1992; 33:1051.
- Cui W, Kobau R, Zack MM, et al. Seizures in Children and Adolescents Aged 6-17 Years - United States, 2010-2014. MMWR Morb Mortal Wkly Rep 2015; 64:1209.
- Berg AT, Shinnar S, Levy SR, Testa FM. Newly diagnosed epilepsy in children: presentation at diagnosis. Epilepsia 1999; 40:445.
- Berg AT, Levy SR, Testa FM, Shinnar S. Classification of childhood epilepsy syndromes in newly diagnosed epilepsy: interrater agreement and reasons for disagreement. Epilepsia 1999; 40:439.
- Wyllie E, Comair YG, Kotagal P, et al. Seizure outcome after epilepsy surgery in children and adolescents. Ann Neurol 1998; 44:740.
- Duchowny M, Levin B, Jayakar P, et al. Temporal lobectomy in early childhood. Epilepsia 1992; 33:298.
- Duchowny M, Jayakar P, Resnick T, et al. Epilepsy surgery in the first three years of life. Epilepsia 1998; 39:737.
- Engel J Jr. Surgery for seizures. N Engl J Med 1996; 334:647.
- Whiting S, Duchowny M. Clinical spectrum of cortical dysplasia in childhood: diagnosis and treatment issues. J Child Neurol 1999; 14:759.
- Marin-Padilla, M. Prenatal development of human cerebral cortex: An overview. Int Pediatr 1995; 10 Suppl 1:6.
- Kuzniecky RI, Barkovich AJ. Pathogenesis and pathology of focal malformations of cortical development and epilepsy. J Clin Neurophysiol 1996; 13:468.
- Leventer RJ, Phelan EM, Coleman LT, et al. Clinical and imaging features of cortical malformations in childhood. Neurology 1999; 53:715.
- Battaglia A. Seizures and dysplasias of cerebral cortex in dysmorphic syndromes. In: Dysplasia of cerebral cortex and epilepsy, Guerrini R, Andermann F, Canapicchi R, et al. (Eds), Lippincott-Raven, Philadelphia 1996. p.199.
- Jamuar SS, Lam AT, Kircher M, et al. Somatic mutations in cerebral cortical malformations. N Engl J Med 2014; 371:733.
- Poirier K, Lebrun N, Broix L, et al. Mutations in TUBG1, DYNC1H1, KIF5C and KIF2A cause malformations of cortical development and microcephaly. Nat Genet 2013; 45:639.
- Lee JH, Huynh M, Silhavy JL, et al. De novo somatic mutations in components of the PI3K-AKT3-mTOR pathway cause hemimegalencephaly. Nat Genet 2012; 44:941.
- Lim JS, Kim WI, Kang HC, et al. Brain somatic mutations in MTOR cause focal cortical dysplasia type II leading to intractable epilepsy. Nat Med 2015; 21:395.
- Leventer RJ, Scerri T, Marsh AP, et al. Hemispheric cortical dysplasia secondary to a mosaic somatic mutation in MTOR. Neurology 2015; 84:2029.
- Jansen LA, Mirzaa GM, Ishak GE, et al. PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia. Brain 2015; 138:1613.
- Fogarasi A, Tuxhorn I, Hegyi M, Janszky J. Predictive clinical factors for the differential diagnosis of childhood extratemporal seizures. Epilepsia 2005; 46:1280.
- Fogarasi A, Janszky J, Tuxhorn I. Peri-ictal lateralizing signs in children: blinded multiobserver study of 100 children < or =12 years. Neurology 2006; 66:271.
- Wyllie E, Friedman D, Rothner AD, et al. Psychogenic seizures in children and adolescents: outcome after diagnosis by ictal video and electroencephalographic recording. Pediatrics 1990; 85:480.
- TYPES OF SEIZURES
- Focal (partial) seizures
- Generalized seizures
- Epileptic spasms
- Impact of age
- Structural or metabolic
- - Hippocampal sclerosis
- - Neurodevelopmental lesions
- CLINICAL CHARACTERISTICS
- Clinical behavior during seizures and nonepileptic events
- INFORMATION FOR PATIENTS