Epilepsy Flashcards
seizure
abnormal, paroxysmal changes in the electrical activity of the brain; they reflect large scale synchronous discharges of neuronal networks
epileptogenesis
the process by which normal brain function progresses towards generation of abnormal electrical activity
epilepsy
a neurological disorder that represents a brain state that supports recurrent, unprovoked seizures
3 classifications of epilepsy
focal onset
generalised onset
unknown onset
generalised onset seizures
affect both sides of the brain from the onset
cortical or subcortical.
focal onset seizures
start in an area or network in one of the brain hemispheres
cortical or subcortical
remain localized or spread to large areas
unknown onset seizures
beginning of seizure uncertain
status epilepticus
life threatening form of epilepsy with seizures >5mins
premonition
vague sense that a seizure is imminent
pre tonic clonic phase
a few myoclonic jerks or brief clonic seizures
tonic phase
tonic contraction of the axial musculature; upward eye deviation and pupillary dilatation; tonic contraction of the limbs; cyanosis; respiratory muscle contraction - “epileptic cry”; tonic contraction of jaw muscles
clonic phase
jerks of increasing amplitude followed by relaxation
postdictal period
generalized lethargy; decreased muscle tone, headaches, muscle soreness
epilepsy diagnosis
2+ seizures >24hrs apart
witness accounts
EEG MRI fMRI PET MRS
how is the hippocampus effected in temporal lobe epilepsy
reorganisation and loss of cells
sclerosis
distortion and compression of layers
gliosis
differential tract organisation
what can cause formation of reverberant excitatory circuits
compensatory sprouting of mossy fibres of granule cells
what can neurogenesis triggered by seizures lead to
aberrant circuits
chandelier cells
GABAergic interneurons that control activity of cortical pyramidal cells
do decreased or increased numbers of chandelier cells lead to abnormal excitatory activity
decreased
secondary epilepsy causes
craniotomy
TBI
stroke
aneurism
brain tumour
CNS infection
what neuronal mechanisms are linked to epilepsy
abnormal neuronal excitability
decreased neuronal inhibition
increased neuronal excitation
2 major glutamate transporters on Glial cells
EAAT1 EAAT2
factors in eliptogenesis
neuroinflammation
BBB breakdown
oxidative stress
gliosis
network and synaptic changes
2 major signalling pathways that may be activated in epilepsy
mTOR pathway
REST pathway
mTOR pathway role
regulates growth and homeostasis
REST pathway role
negative regulation of many genes in CNS
what cellular component issue is a major part of epilepsy
channelopathy
epilepsy drugs mainly targeting sodium channels
phenytoin
carbamazepine
sodium valproate
lamotrigine
topiramate
lacosamide
zonisamide
epilepsy drugs mainly targeting Ca channels
ethosuxinimide
gabapentin
which epilepsy drugs are teratogenic
phenytoin
sodium valproate
phamacokinetic order of phenytoin
0 order
which epilepsy drugs induce liver enzyme production
phenytoin
carbamazepine
which antiepileptic drugs mainly targeting sodium channels also affect other channels
lamotrigine - calcium, inhibit glutamate release
topiramate - augment GABAa receptors, inhibit glutamate AMPA signalling
zonisamide - blocks calcium channels
how does gabapentin affect GABA synthesis
increase
how do gabapentin and pregabalin affect calcium channels
Target alpha2delta subunit to disrupt delivery of VG calcium channels to cell membrane
benzodiazepines and barbituates MOA
GABAa positive allosteric modulator
Ben incr opening freq
Barb incr opening duration
main action of levetiracetam
modulates NT release by binding to synaptic vesicle protein SV2A inhibiting presynaptic calcium channels
tiagabine MOA
inhibits GABA reuptake by inhibiting GAT1 transporter
vigabatrin MOA
inhibits GABA transaminase
which receptors do perampanel and felbamate affect
perampanel - AMPA agonist
felbamate - NMDA blocker
what type of drug is clonazepam
benzodiazapine
what type of drug phenobarbitone and stiripentol
barbituates - pheno
Stiri is new drug w similar action to barbituates
main drugs used for focal seizures
carbamazepine
lamotrigine
sodium valproate
main drugs used for tonic clonic seizures
carbamazepine
lamotrigine
sodium valproate
main drugs for absence seizures
ethosuximide
sodium valproate
main drugs for myoclonic seizures
sodium valproate
clonazepam
levetiracetam
status elipticus treatment
IV lorazepam/diazepam
surgeries for epilepsy treatment
lobe resection
corpus callosotomy
functional hemispherectomy
which type of diet can be beneficial in epilepsy
ketogenic
types of neuromodulation therapy that can help epilepsy
vagal nerve stimulation
deep brain stimulation
transcranial magnetic stimulation
