46 - Patho of Seizure Disorders Flashcards
> ___ % of all patinets with epilepsy will experience their first seizure by age 20
- a second peak occurs in the ___
80%
elderly
Generalized seizures (nono-absence types)
Myoclonic
- ___ like contraction of ___
- isolating jerking of head, trunk, body
shock
muscles
Generalized seizures (non-absence types)
Tonic
- these seizures occur in ___
- involve ___ as a result of increased tone in extensor muscles
- children
- rigidity
Generalized seizures (non-absence types)
Clonic
- these occur in ___ and young ___
- involve ___ , repetitive motor activity
babies, children
rigidity
Generalized seizures (non-absence types)
atonic
- sudden loss of ___ tone
- patients fall if standing (“drop attacks”)
jello moment
muscle
Generalized seizures (non-absence types)
tonic-clonic
- ___ phase immediately followed by ___ phase
- referred to as “ ___ ___ “
- characteristic of epilepsy
tonic, clonic
grand mal
Definitions
Seizure - ___ disorder of the CNS characterized by abnormal cerebral neuronal dischargers with or without loss of consciousness
- disordered, ___ , and rhythmic firing of population of brain neurons
Paroxysm - ___ attack or outburst
paroxysmal
synchronous
sudden
Definitions
Convulsion - specific seizure type where the attack is manifested by ___ muscle ___
Epilepsy - ___ seizures due to damage, irritation, and/or chemical imbalance. Leads to sudden, excessive, synchronous ___ discharge
involuntary, contractions
repeated, electrical
T or F: a seizure can cause cell ischemia because the brain is using more energy than it can manufacture
T
Seizure classifications
focal onset
- aware or impaired awareness
- motor onset or non-motor onset
- may progress from focal to ___ tonic-clonic
generalized onset
- motor:tonic clonic or other motor
- non-motor ( ___ )
unknown onset
- motor: tonic clonic or other motor
- nonmotor
- unclassified
bilateral
absence
Seizure classification
Focal
- about __ %
- only part of the brain is affected
- begin focally in cortical region, example: ___
- usually due to lesion from head trauma, tumor, stroke, hypoxia at birth, metabolic disorder, infections, malformations
- frequently process to generalized seizure ( focal to ___ )
- 60%
- temporal lobe
- bilateral
Seizure classification
generalized
- __ % of seizures
- loss of ___
- both brain ___ involved
- referred to as primary of idiopathic (if not evolved from ___ seizures)
- most are presumed to be ___
- 40%
- consciousness
- hemispheres
- focal
- genetic
pathways for the propagation of focal and generalized seizures
Partial seizure - seizure activity spreads from a focus in one part of the brain ( ___ )
Secondary generalization - focal seizures frequently progress to secondary generalized seizure via projections to the thalamus (latest classification” focal to ___ seizure)
Primary generalized seizure - propagate via diffuse interconnections between the thalamus and cortec (no discrete ___ ). the earliest clinical signs show involvement of ___ brain hemispheres
- focal
- bilateral
- focus, both
brain waves
T or F: focal and generalized seizures yield different EEG pattens
F
focal - aware
focal seizures can be of the “aware: type or involved impaired awareness
aware type (previosuly referred to as simple partial)
- 25% of focal seizures
- limited convulsions (jerking of ___ limb or body part)
- limited sensory disturbance
- no loss of ___
- subjective experiences ( ___ ) also occur - abdominal discomfort, sense of fear, unpleasant small, result of abnormal electrical activity
single
consciousness
aura
focal - impaired awareness
previously referred to complex partial
- most common among focal seizures
- ___ of consciousness
- staring
- repetitive motor behaviors ( ___ , pts dont remember) lip smaking, chewing, swallowing
- disturbances of visceral, emotional, and autonomic systems
- seizure followed by confusion, fatigue, throbbing headache
- ___ is common
- ___ state due to impaired awareness
- clouding
- automatisims
- aura
- postictal
postictal state
may last for seconds to hours depending on ___ of the brain, ___ of seizure, use of anti-epileptic drugs, age
symptoms
- confusion
- disorientation
- anterograde amnesia
area, length
hang over after seizure
generalized seizures (absence type)
typical (petit-mal)
- brief loss of consciousness (10-45 sec)
- ___ or eye flickering
- begin ___
- often repetitive
- may not realize it after the seizures
- no ___, ___, or ___ period
atypical
- ___ onset
- more difficult to control with drugs
- staring
- abruptly
- convulsions, aura, postictal
- slower
generalized tonic-clonic (grand mal) seizure
most ___ of all epileptic seizures
___ phase
- begins abruptly, no ___ , rigidity
- interrupted by a tremor that correponds to relaxation
___ phase
- begins as relaxation period becomes prolonged
- after jerking, patients are in stuporous state
tongue/cheek may be bitten, urinary incontinence
primary gen. tonic-clonic show no evidence of ___ onset
focal to bilateral tonic-clonic seizures start out as focal, there can be a brief ___ in this case
dramatic
tonic
- aura
clonic
localized
aura
Status eilepticus
generalized convulsive status epileptic (GCSE)
- ___ seizure activity in which the pt does not regain ___ between seizures OR
- a continuous, single seizure episode lasting over ___ min
- greater than ___ min of continuous seizure OR
- recurrent seizure activity without an appropriate return to ___
- could be life threatening
Therapeutic goal: bring seizures under control within ___ min
- repetitive, consciousness
- 30
- 5
- baseline
- 60
Epilepsy statistics
- incidence of epilepsy: 1-2%
- one seizure does not make an ___
- drug therapy can be gradually withdrawn in patients who have been clinically free of seizures for ___ - ___ years
- sudden unexpected death in epilepsy (SUDEP) could occur
- epilepsy
- 2-5
which of the following types of the convulseions can be preceded by an aura phase?
A) typical absence (petit mal)
B) primary generalized toni-clonic (grand mal)
C) focal to bilateral (secondary generalized) tonic-clonic
D) all of the. above
C) focal to bilateral (secondary generalized) tonic-clonic
Paroxysmal depolarizing shift (PDS)
- PDS consists of a large depolarization that triggers a burst of ___
- ___ involves the activation of (1) AMPA and NMDA channels by the excitory neurotransmitter ___ , and (2) voltage-gated Ca channels (gCa), leading to an ___ of Ca ions
- followed by ____ involving the activation of ___ receptors ( ____ of Cl ions) and voltage gated ___ depended K channels (gK), leadinfg to ___ of K
- neuronal signaling ( ___ ) is normally dampened by feed-forward and feedback inhibition - involving GABAergic neurons in a typical cortical neuron circuit
- disrupted ___ / ___ balance
- action potentials
- depolarization, glutamate, inlux
- hyperpolarization GABA, influx, Ca, efflux
- depolarization
- excitation/inhibitory (E/I)
seizure focus and inhibitory surround
electrical discharge spreads thrpugh the sizure focus but is contained as a result of inhibtion in a neighboring zone called the ___ ___
- an excitatory pyramidal neuron (A) activating another pyramidal neuron (B), whereas neuron (C) in the surround inhibited regions is ___ because of GABAergic inhibition
inhibitory surround
- hyperpolarized
electrophysiological basis for the tonic and clonic phases of a generalized tonic-clonic seizure
- evolution from focal to bilateral involves a loss of ___ and surround inhibition
- tonic phase: ___ mediated inhibition disapperas, whereas ___ mediated AMPA and NMDA receptor (via influx of cations) activity increase
- clonic phase: ___ mediated inhibition (via influx of ___ ions) gradually returns, leading to period of oscillation
- as GABA mediated inhibtion breaks down during the ___ phase, action potentials propagate to distant neurons, leading to spread of seizure activity from focus to distant sites in the brain
- hyperpolarization
- GABA, glutamate
- GABA, Cl
- tonic
potential triggers of status epilepticus
underlying conditions in the brain:
- prenatal injury
- cerebrovascular disease
- brain tumors
- head trauma
- infection
- hemorrhage
- anoxia
- drugs
general perturbations
- metabolic disturbances (hyperventilation, blood gas/pH, hypoglycemia
- sleep deprivation
- stress
- alcohol withdrawal
- withdrawal or sudden D/C of ___
- repetitive light stimulation (strobes)
AEDs
drugs that aggravate or increase the risk of seizures
- alcohol
- theophylline
- phenothiazines
- tramadol
- meperidine
- ___ stimulants
- bupropion
- imipenem
- oral ___
- withdrawal from ___
- memantine
___ (converted to norclozapine via CYP1A2, increases seizure risk) -
- CNS
- contraception
- depressants
- clozapine
Which of the following occurs during the hyperpolarization phase of a PDS?
A) influx of Cl ions resulting from GABAA receptor activation
B) influx of K through voltage and calcium dependent K channels
C) activation of NMDA receptors
D) all of the above
PDS = paroxysmal depolarizing shift
A) influx of Cl ions resulting from GABAA receptor activation
