Epilepsy

Question 1

Seizure

Answer 1

excessive + abnormal activity between cortical neurons
excessive hypersynchronous neuronal cortical discharge
transient (sudden onset) occurrence (usually <2min duration)

leads to loss of consciousness, shaking + uncontrolled movement, loss of muscle control

Question 2

generalized seizure

Answer 2

whole brain fires at once
communication between networks

Question 3

focal seizure

Answer 3

one area is firing excessively
can become generalized if seizure activity spreads through thalamus cortical network

Question 4

appearance of seizure

Answer 4

determined by where it is propagating (not necessarily where it originates)
networks of spreading

Question 5

classification of seizure types

Answer 5

focal onset
generalized onset
unknown onset

Question 6

focal onset

Answer 6

awareness - impaired
motor/non-motor onset
focal to bilateral tonic-clonic

division of motor/non-motor onsets

Question 7

generalized onset

Answer 7

motor → tonic-clonic, other motor
non-motor: absence

further division of motor/non-motor

Question 8

unknown onset

Answer 8

motor/non-motor
unclassified

motor → tonic-clonic/epileptic spasms
non-motor → behaviour arrest

Question 9

electrographical definition of seizures

Answer 9

a clear ictal with sudden, repetitive waveform with defined start, middle, and end

ictal: intense electrical activity

Question 10

epilepsy

Answer 10

enduring predisposition to seizures - risk/frequent occurrence
1. two+ unprovoked or reflex seizures within 24 hours
2. a single unprovoked/reflex seizure + >60% risk of re-occurrence
3. epilepsy syndrome (genetics)

Question 11

epilepsy classification

Answer 11

focal
generalized
combined generalized and focal
unknown

Question 12

epilepsy etiology

Answer 12

structural - brain malformation
genetic - predisposition
infectious - ex. HSV
metabolic - low Na+, glucose
immune - auto-immune, encephalitis
unknown - childhood epilepsy is commonly unknown

rates change with age

Question 13

seizures in children

Answer 13

different mechanisms of epileptogenesis → babies’ brains are very excitatory - working to develop new networks and connection in short time = easy to become over-excited
different propagation of seizures → not yet myelinated
unique EEG patterns
different responses to medications
different clinical manifestations

Question 14

ictal apnea

Answer 14

stopped breathing
normal EEG, MRI
cEEG showed subtle signs of seizure
treated with antiseizure medications

likely originated in limbic system
genetic syndromes (1p36 deletion, T18, SCN8A)
mesial temporal lesions
maturation related susceptibility → in posterior limbic cortex, temporal lobe, and midbrain respiratory centers

Question 15

autonomic manifestations of seizures

Answer 15

ex. hypersalivation
nighttime only, stereotypical (same each time) + short, multiple times per night, no recollection
EEG showed differences in activity between hemispheres

focal seizures - ictal hypersalivation
autonomic manifestations → maturation-related susceptibility of the central autonomic network; lower threshold for epileptogenic activation

Question 16

frontal sleep related hyper-motor epilepsy

Answer 16

frequent nighttime arousals
stereotyped, abrupt onset and offset

brief, highly stereotyped seizure during nREM sleep
classic frontal lobe epilepsy - disorganized, lots of movement
genetic or structural causes (focal cortical dysplasia type IIb)
overlap with parasomnias

Question 17

parasomnias

Answer 17

pre-school age, childhood
first 1/2 of night
N3 sleep
5-30 min
single event/night
normal EEG
normal daytime behaviour
benzodiazepines

Question 18

nocturnal seizures

Answer 18

anytime in infancy through adolescence
randomly through night
N1/N2 stages of sleep
brief <5 min
multiple events/night
abnormal or normal EEG
possible daytime seizures
sodium channel blockers

Question 19

video EEG

Answer 19

valuable tool in assessment of children with suspected seizures
can support diagnosis of epilepsy - determine type, guide management

Question 20

Neonatal seizures

Answer 20

seizures are more common in neonates - different presentations and causes
1. GABA-A receptors are excitatory
2. developmental imbalance between excitatory and inhibitory mechanisms
3. delayed maturation of GABA-B, adenosine, and 5-HT receptors
4. high density of NMDA receptors in hippocampus and neocortex

Question 21

neonatal GABA-A receptors

Answer 21

excitatory rather than inhibitory
excitation is more important in neonatal development → abnormal flow in receptor
excessive excitation = more susceptible to seizures

Question 22

developmental imbalance between excitatory and inhibitory mechanisms

Answer 22

electrochemical dissociation: GABA-A receptors mature in the spinal cord first = become inhibitory sooner than the brain’s receptors → seizure will continue in cortical GABA-A receptors but won’t show in the spinal cord (movement) because of difference in time of maturation

Question 23

clonic seizures

Answer 23

activity
rhythmic jerks
focal (one side) or multi-focal
most common cause is stroke

Question 24

subtle seizures

Answer 24

hard to tell without EEG
abnormal eye movements

Question 25

cause of neonatal seizures

Answer 25

babies likely don’t have epilepsy
symptomatic cause - infection, stroke, some dysfunction in brain
affect homeostasis

Question 26

EEG in neonates

Answer 26

assessment of cerebral function and maturation
neurological injury
at <28 weeks, occipital area seizes the most - later decreases in frequency

conventional EEG - electrodes on scalp, measures currently (min); good spatial coverage

amplitude integrated EEG - less electrodes → compression of EEG, measures continuous (hours-days) - pattern recognition; easy to interpret but limited spatial coverage
medications can depress the background of aEEG

Question 27

maturational changes

Answer 27

shown on aEEG
lots of activity and large spikes at 23 weeks
less drastic spikes at 34 weeks

Question 28

Congenital Heart Disease - seizure

Answer 28

mildly abnormal EEG
coarctation of aorta
unilateral rhythmic clonic movements

KCNQ2 mutation - K+ channel
unique pattern on ictal EEG/aEEG → seizures
antiseizure meds didn’t work but sodium channel medication did

Question 29

KCNQ2 associated neontal epilepsy

Answer 29

most common of neonatal epilepsy
- self-limited neonatal epilepsy: seizures between 4-6 days of life; clonic seizures, with or without apnea
- developmental epileptic encephalopathy: presentation depends on pathogenic mutation (loss or gain of function); tonic seizures and markedly abnormal EEG

Question 30

EEG - artifacts

Answer 30

physiological: muscle; movement
ex. sucking artifact, back patting - will show on EEG
non-physiological: electrical; mechanical; impedance

Question 31

abnormal paroxysmal (sudden) events in neonates

Answer 31

apnea
jitteriness
hyperekplexia
ocular signs
oral-buccal-lingual movements
complex movements
tonic posturing
abrupt change in vital signs