Exam 3 - Rochet/Ott (Seizures) Flashcards
3 main ways to classify seizures
Focal Onset
Generalized Onset
Unknown Onset
how to classify Focal Onset Seizures
Aware or Impaired awareness
and
Motor or Nonmotor onset
common reason for causes of focal seizures
usually due to a lesion
head trauma/tumor/stroke/hypoxia at birth/metabolic disorder/ infection/malformations
common reason for generalized seizures
NOT due to lesion—- presumed to be genetic!
Generalized seizures are known to cause the patient to be aware or non-aware?
non-aware — pt lose consciousness
Focal seizures can progress to secondary generalized seizures via projections to the ______
thalamus
what are possible symptoms of an aura before a seizure
abdominal discomfort
sense of fear
unpleasant smell
result of abnormal electrical activity
what are automatisms?
repetitive motor behaviors
swallowing, chewing, lip smacking
special aspects of impaired awareness focal seizures:
repetitive motor behaviors
disturbances of visceral/emotional/autonomic
seizure followed by confusion/fatigue/throbbing HA
what is postictal state
after seizure —- pt will not recover a normal level of consciousness immediately
symptoms of postictal state
confusion
disorientation
anterograde amnesia
Generalized Seizures:
Absence —- can be ______ or _______
atypical
or
typical
Describe Typical Absence Generalized Seizures
brief loss of consciousness staring or eye flickering begins ABRUPTLY often repetitive (NO convulsions, aura, or postical period)
Describe Atypical Absence Generalized Seizures
SLOWER ONSET
more difficult to control pharmacologically than typical
Generalized Seizures – two main subgroupings
Abscence or Non-Abscence
What are Non-Abscence Generalized Seizures?
Myoclonic Tonic Clonic Atonic Tonic-Clonic Status Epilepticus
which Non-Abscence Generalized Seizures?
shock-like contraction of muscles
and
isolated jerking of head, trunk, and body
Myoclonic
which Non-Abscence Generalized Seizures?
involve rigidity as a result of increased tone in extensor muscles
and
occur in children
tonic
increased tone = tonic…
which Non-Abscence Generalized Seizures?
involve rapid/repetitive motor activity
occur in babies/young kids
clonic
which Non-Abscence Generalized Seizures?
sudden loss of muscle tone
and
patients fall if standing “drop attacks”
Atonic
which Non-Abscence Generalized Seizures?
referred to as grand mal
tonic-clonic
which Non-Abscence Generalized Seizures?
known as single prolonged seizure
status epilepticus
Describe Tonic Clonic Seizure
Tonic: 15 - 30 seconds of tonic rigidity in all extremities (happens abruptly — NO aura)
Clonic: 1 - 2 minutes —involves violent jerking
may bite tongue or cheek
urinary incontinence is common
Drug therapy can be GRADUALLY withdrawn in pts who have been clinically free of seizures for _______(how long…?)
2 - 5 years
what is PDS
paroxysmal depolarizing shift
it is large depolarization that triggers burt of action potentials
Pathophysiology of Seizures:
Depolarization involves activation of _____ and _____ channels also _______ channels
AMPA; NMDA; voltage gated Ca2+
Pathophysiology of Seizures:
Depolarization activates channels by the ________ neurotransmitter (known as ______) and and leads to _____ influx
excitatory; glutamate; Ca2+
Pathophysiology of Seizures:
Hyperpolarization involves activation of ______ receptors and ______ channels
GABA; and calcium gated POTASSIUM channels
Pathophysiology of Seizures:
Hyperpolarization leads to a ____ efflux
K+
Pathophysiology of Seizures:
_____ neurons are used to dampen neuronal signaling
by feed forward or feedback inhibition
GABAergic
Pathophysiology of Seizures:
what is inhibitory surround
it is hella GABA neurons connected to glutamate to inhibit an electrical discharge from spreading
Pathophysiology of Seizures:
Tonic Phase Seizures — _______ mediated inhibition dissapears
GABA
Pathophysiology of Seizures:
Tonic Phase Seizures —- ________ mediated activity increases
glutamate
AMPA and NMDA receptor
Pathophysiology of Seizures:
In Clonic Phase: ______ mediated inhibition gradually ______ which causes a period of _______
GABA; gradually returns; period of Oscillation
Pathophysiology of Seizures:
In the tonic phase — when ______ mediated inhibition breaks down —- the action potentials do what?
GABA mediated;
action potentials propagate to distant neurons
allllllll the potential triggers of status epilepticus
prenatal injury cerebrovascular disease brain tumors head trauma infection hemorrhage anoxia drugs
metabolic disturbances sleep deprivation stress alcohol withdrawal withdrawal from AEDs (especially quickly) repetitive light stimluation
Drugs that may increase the risk of seizures
alcohol theophylline bupropion oral contraceptives withdrawal from depressants CNS stimulants clozapine
why is clozapine related to increase risk of seizures
clozapine converted to norclozapine via CYP1A2 and norclozapine increases seizure risk
what is the definition of seizure
paroxysmal disorder of CNS —- abnormal neruonal discharges with or without loss of consciousness
what is the definition of convulsion
specific seizure where attack is manifested by involuntary muscle contractions
what is the definition of epilepsy
repeated seizures due to damage/irritation and or chemical imbalances in brain
Two synapses are targeted for Anticonvulsant drugs — what are the two synapses
Glutamate (excitatory) and GABA (inhibitory)
For Excitatory Synapse Drug Targets:
What are the Presynaptic targets
and
what are the postsynaptic targets
pre: Na+ channels and Ca2+ channels
post: NMDA and AMPA receptors
For Inhibitory Synapse Drug Targets:
What are the Presynaptic targets
and
what are the postsynaptic targets
Pre: GABA transporter (GAT-1) and GABA transaminase (GABA-T)
Post: GABA(A) receptors and GABA(B) receptors
List the drugs that decrease sodium influx
carbamazepine oxcarbazepine phenytoin lacosamide lamotrigine valproate
List the drugs that decrease calcium influx
**This is CRITICAL for abscence seizures!!
ethosuximide
lamotrigine
valproate
List the drugs that enhance GABA mediated inhibition
BZDs barbituates valproate gabapentin viganatrin tiagabine
List the drugs that antagonize excitatory tranxmitters (ex: glutatmate)
felbamate
topiramate
what drugs activate the GABA(A) receptor
barbituates
and
benzodiazepines
what drugs increase GABA levels
valproate
what drugs increase GABA release
gabapentin
what drugs inhibit GABA transaminase
vigabatrin
what drugs inhibit GAT-1
tiagabine
what drug is a NMDA receptor antagonist
felbamate
what drug is an antagonist of AMPA receptors
topiramate
MOA of phenytoin
binds and stabilizes the inactivated state of Na+ Channel
what is the therapeutic plasma level for phenytoin
7.5 - 20 ug/mL
Phenytoin has (linear or non-linear) pharmacokinetics
NON-linear!
drug interactions with Phenytoin
can be displaced from plasma proteins by other drugs (which leads to increase in phenytoin concen.)
and it induces CYP450 - increases metab of other drugs
ADEs of Phenytoin
Arrhthymia Ataxia GI symptoms Sedation (@ high doses) Gingival Hyperplasia Nystagmus or Diplopia Hisutism hypersensitivity reactions
which drug(s) is a part of the Hydantoin class
phenytoin
which drug(s) is a part of the Iminostilbene class
carbamazepine
and
oxcarbamazepine
which one has reduced toxicity?
oxcarbamazepine
or
carbamazepine
oxcarbamazepine
MOA of Carbamazepine
bind and stabilize Na+ channel into inactivated state
ADEs of Carbamazepine
blurred vision ataxia GI disturbances sedation at high doses serious skin rash DRESS hypersensitivity reaction
what is the brand of Lacosamide
Vimpat