Lecture 15: Seizures and Epilepsy Flashcards
What is a seizure?
an excessive hypersynchronous neuronal cortical discharge
a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain (usually less than 2 minutes in duration)
What is a generalized seizure?
whole brain fires at the same time
What is a focal seizure?
one area is firing
focal can become generalized
What are the different types of focal onset seizures?
aware, impaired awareness
motor onset: automatisms, atonic, clonic, epileptic spasms, hyperkinetic, myoclonic, tonic
non-motor onset: autonomic, behavior arrest, cognitive, emotional, sensory
What are the different types of behavioral onset seizures?
motor: tonic-clonic, clonic, tonic, myoclonic, myoclonic-tonic-clonic, myoclonic-atonic, atonic, epileptic spasms
non-motor (absence): atypical, typical, myoclonic, eyelid myoclonia
What are the different types of unknown onset seizures?
motor: tonic-clonic, epileptic spasms
non-motor: behavior arrest
What is epilepsy?
enduring predisposition to seizures
one of these diagnoses:
1. two or more unprovoked or reflex seizures >24 hours apart
2. a single unprovoked seizure of reflex seizure + a >60% risk of having another seizure over the next 10 years
3. an epilepsy syndrome
What are the different types of epilepsy?
focal
generalized
combined generalized and focal
unknown
What are the causes of epilepsy?
structural
genetic
infectious
metabolic (low sodium)
immune (autoimmune encephalitis)
unknown
What are the differences in seizures in children compared to adults?
different mechanisms of epileptogenesis
different propagation of seizures
unique EEG patterns
different responses to medications
different clinical manifestations
What is the definition of a seizure as seen on a electrographic?
a clear ictal even comprising of a sudden, repetitive, involving stereotyped waveform with a definite start, middle, and end
What is ictal apnea?
pathophysiology unknown, likely originating in limbic system
genetic syndromes (1p36 deletion, T18, SCN8A)
mesial temporal lesions
What are seizures with apnea?
apnea can be ictal especially in young children
video EEG needed for diagnosis
video EEG can identify subtle non-autonomic manifestations
What are autonomic manifestations during seizures?
maturation-related susceptibility of the central autonomic network
lower threshold for epileptogenic activation
What are the key points regarding diagnosing seizures in children?
thorough history and event description
stereotypical brief episodes warrant further work-up
capturing the episodes on video EEG will provide the diagnostic clues
What is the relationship between nocturnal seizures and parasomnias?
differentiating nocturnal seizures from parasomnias can be challenging
ictal and interictal EEGs can be normal or non-specifically abnormal
etiology: genetic, structural (focal cortical dysplasia type IIb)
What is frontal sleep related hypermotor epilepsy?
during NREM sleep
brief, highly stereotyped
occurrence in sleep, overlap with parasomnias
seizures are brief, sleep disorders are a lot longer
What are the characteristics of parasomnias?
pre-school age, childhood
first 1/3 of the night
N3 sleep
5-30 minutes
single event per night
EEG normal
normal daytime behavior
respond to benzodiazepines at bedtime
What are the characteristics of nocturnal seizures?
anytime infancy through adolescents
randomly through the night
N1/N2 stages of sleep
brief, less than 5 minutes
multiple events per night
EEG normal or abnormal
irritable, tired, can have daytime seizures
response to sodium channel blockers, levetiracetam
What is a summary of the diagnosing of children with epilepsy?
video EEG is a valuable tool in assessment of children with suspected seizures
EEG can support the diagnosis of epilepsy, and it may assist in determining the type of or epilepsy and guide the management
child with unexplained stereotypical episodes, when seizures are a possibility, should have an EEG, ideally awake and sleeping
How common are seizures in neonates?
depends on whom you ask
hard to tell actual numbers because of:
1. heterogenous groups
2. variable practices
3. variable monitoring techniques
Why are seizures more common in neonates?
GABA-A receptors excitatory rather than inhibitory
developmental imbalance between excitatory and inhibitory mechanisms
delayed maturation of GABA-B, adenosine, and 5HT receptors
high density of NMDA (excitatory) receptors in hippocampus and neocortex
What is gluatamate?
main excitatory neurotransmitter of the brain
What is GABA?
main inhibitory neurotransmitter of the brain (except in neonates)
