Epilepsy CC1 Flashcards
partial (focal) seizure involves
1 hemisphere
generalized (global) seizure involves
both hemispheres
simple partial means
- no LOC
- single hemisphere
complex partial means
- impairment of conciousness, but can still be awake
- single hemisphere
secondarily generalized means
starts partial, then becomes generalized
where do generalzied seizures start?
in subcortical structures
abscense seizures involve
loss of consciousness without motor
symptoms.
tonic generlized seizures involves
sustained contraction of muscles
clonic seizures involve
repetitive movements (like shaking)
tonic clonic seizures involve
start as tonic, then become clonic
atonic seizures involve
negative sx, loss of muscle tone
how do you distinguish between complex partial seizure and abscence seizure?
eeg
subtypes of generalized seizures
- abscence
- tonic
- clonic
- tonic-clonic
- atonic
what is epilepsy
the enduring predisposition to generate epileptic seizures
idiotpathic seizures are usually
genetic
what can cause epileptic channelopathies
mutations in voltage gated ion channels, can cause gain or loss of function
what is the inheritance pattern of channelpathies?
what kind of mutations are they mostly?
most are autonosomal dominant
mostly de novo
when do febrile seizures occur
occurring in childhood after 1 month of age
what are febrile seizures associated with?
associated with a febrile illness not caused by CNS infection
no hx of previous seizures & not acutely symptomatic
febrile seizure is a ___ channelopathy
Na 1.1
Generalized Epilepsy with Febrile Seizures Plus invovles mutations in
SCN1B or SCN1A
with Generalized Epilepsy with Febrile Seizures Plus you get a loss of
loss of fast inactivation –> Na channel gain
of function –> persistent Na current
with Severe Myoclonic Epilepsy of Infancy you get a loss of
loss of high frequency action potential --\> loss of inhibitory function of GABAergic cortical interneurons & Pukinje cells --\> seizures & ataxia
signs of Severe Myoclonic Epilepsy of Infancy in first year?
seizures associated with high body temp (fever, bathing) –>
seizures get progressively prolonged and cluster
what are the signs of Severe Myoclonic Epilepsy of Infancy?
show psychomotor delay, ataxia, cognitive impairment
what is the range of severity of Na 1.1 channelpathies?
sx of Benign Familial Neonatal Convulsion
brief generalized and partial seizures that usual resolve by age 6 weeks
K Channelopathies in Epilepsy invovles loss of function of what receptor?
Loss of Function from mutations in Kv7.2 and Kv7.3
K Channelopathies in Epilepsy involve gain of function from
mutation in the pore-forming subunit
KCNMA1) encodes
the pore formiung suybunit involved in generalized epilepsy & paroxysmal dyskinesia
what does loss of K poreforming subunit result in?
–> increased K flux –> generalized epilepsy & paroxysmal dyskinesia
Ca and Cl Channelopathies in Epilepsy Both can lead to
idiopathic generalized epilepsy
Mutations in CLCN2 –> results in
↓ Cl gradient, less GABAergic hyperpolarization
Antiepileptic drugs decrease the ___ of neurons
hyper-excitability
2 mechanism in which antielipetic drugs work?
- block Na channels
- increase inhibitory neurons via GABA
wjhat regulates the function of Na and Ca channels?
B subuniots
describe the general structure of Na and Ca channels
6 membrane spanning regions x 4
describe the general structure of K+ channels
6,2,4,7 membrane spanning regions
with a seizure…
abnormal excessive and synchornous electrical discharges of brain neuronal network leads to
paroxysmal events characterized by clinical signs or sx
ictal refers to
seizure period or events due to seizure
aura is ictal or preictal?
ictal
prodrome is precital or ictal?
preictal
variations of simple partial seizures?
with:
- motor signs
- with somatosensory sx
- ANS sx
- psychic sx
ILAE classification divides seizure into
idiopathic, symptomatic, cryptogenic
first division of ILAE classification is?
second division?
first – localization vs. generalized
second – idiopathic, cryptogenic, etc
where are Na 1.1 and Na 1.3 found
in cell bodies
where are Na 1.2 found
unmyelinated axons and dendrites
where are Na 1.6 found
myelinated axons and dendrites
what leads to ataxia with SMEI?
loss of high frequency ap –> loss of inhibitory gaba purkinje cells
what is the pathophysiology of seizures with SMEI?
loss of high frequency AP —> loss of inhibiotry function of gabaeric cortical interneurons –> seizures
to tx SMEI you have to reestablish
gabergic transmission
two drugs for SMEI?
tiagabine (dec gaba reuptake)
benzos (inc response of post synaptic gaba)
how do benzos work for SMEI?
inc response of post synaptic gaba
how does tiagabine work for SMEI?
dec reuptake of GABA
SCN mutations (causing Febrile plus) are usually ___ mutations
missense
tx of febrile plus involves
antipletpic meds that potentially bind tommutant channels and stabilize folding of proteins
mutations in Na 1.1 causing febrile seizures usually results in what two things?
- reudction of peak na current
- positive shift in voltage dependece of activation
K channelpathies mostly invovle cells with __ current
M current (close to resting ptoential and is regualted by msucarnic and other g protein)
disorder assocaited with decreased m current
benigin familar neonatal convulsion
describe Cl channels
12 transmembrane segments
mutations in the CLCN2 gene can lead to
idiopathic generalzied epilepsy
result of gain of function of Ca channels
excessive snchonous rhytmic burst firing –> idiopathic generalized epilepsy
t type ca channels are notable because they
ave rhythmic burst firing
are all seizures channelopathies?
no!
surgery should be considered in ___ epilepsy
localization realted epilepsy that does not respond to 2 medications
how do AEDS stabilize or block Na channels
they prolong the inactive states
