Seizures, Partial and Generalized

Basics

Description

Seizures arise from abnormal electrical discharges in the cerebral cortex that lead to alterations of consciousness, behavior, motor activity, sensation, or autonomic function. Epilepsy is a disease defined as (i) two or more seizures without acute provocation, (ii) one seizure and >60% further risk of additional seizures, or (iii) diagnosis of an epilepsy syndrome. Seizures are classified as focal, generalized, unknown, and focal to bilateral based on where the seizure starts.

Focal seizure types
- Awareness should be described as focal aware, focal impaired awareness, or awareness unknown.
- Motor and other symptoms should be described as focal motor seizure and focal nonmotor seizure.
Aura is not in the updated classification but can still be used to describe a feeling at the beginning of a seizure.
Generalized seizure types
- Tonic–clonic, absence, myoclonic, clonic, tonic, atonic
Unknown onset seizure types: epileptic spasms, behavior arrest
Focal to bilateral seizure is used to describe a seizure that is focal in onset and evolves into a generalized seizure.

Epidemiology

Incidence

Epilepsy affects 0.5–1% of all children (birth through 16 years). 120,000 children seek care annually in the United States for a seizure. Between 20,000 and 45,000 children per year are diagnosed with epilepsy; highest risk is in the 1st year of life.

Prevalence

4 to 10 per 1,000 children in developed countries have epilepsy.

Etiology

Structural
- Brain tumor
- Malformations of cortical development
- Prior stroke
Genetic
Infectious
- Neurocysticercosis
- Cerebral malaria
Metabolic
- Aminoacidopathies
- Pyridoxine-dependent epilepsy
Immune
- N-methyl D-aspartate (NMDA) receptor encephalitis
Unknown cause

Risk Factors

Genetics

Epilepsy is both polygenic and multifactorial.
There are currently >400 single genes known to be associated with epilepsy in childhood.
Copy number variations encompassing deletions and duplications of various sizes have also been implicated in the genetics of epilepsy.
The risk of epilepsy with an affected primary relative increases from the population risk (1–2%) to 4–8%.
Epilepsy may also be a feature of other genetic disorders such as trisomy 21 and Angelman syndrome or be part of a larger neurodevelopmental presentation.

Commonly Associated Conditions

The incidence of childhood-onset epilepsy associated with intellectual disability and cerebral palsy is 15–38%.
Epilepsy occurs in 8–28% of children with autism.
Attention deficit hyperactivity disorder (ADHD), depression, and anxiety are more common in children with epilepsy than in the general population.

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