9/29 Seizures/Epilepsy - Bhise Flashcards Preview

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Flashcards in 9/29 Seizures/Epilepsy - Bhise Deck (35):
1

terminology:

 

ictal

post-ictal

interictal

ictal: during a seizure

post-ictal: immediately following seizure

interictal: time between seizures

2

Todd's paresis

post-ictal contralateral hemiparesis

3

epileptiform

on EEG, discharge with appearance of being potentially epileptogenic (spike or sharp wave)

4

seizure

  • transiet episode with signs/sx of abnormal excessive synchronous neuronal activity in brain
  • physical manifestations vary based on pattern of network involvement in brain

5

mapping old terminology to current terminology

 

grand mal

petit mal

grand mal → generalized

petit mal → focal/partial onset/absent

6

seizure classification

 

two general types

multiple subtypes

1. general

  • tonic-clonic
  • tonic: only stiffening
  • clonic: only rhythmic jerking
  • myoclonic: rapid brief jerks
  • atonic/astatic: loss of postural tone
  • absence: brief staring spells

2. focal/partial

  • simple partial: no altered consciousness
  • complex partial: alteration of consciousness
  • secondary generalized

7

generalized tonic-clonic convulsion

bilateral tonic stiffening of extremeties alternating with clonic jerking

  • impaired consciousness
  • sympathetic sx: tachycardia, mydriasis
  • mild cyanosis at mouth, distal extremities
  • foaming at mouth
  • urinary incontinence
  • lateral tongue biting
  • post-ictal fatigue, weakness, amnesia

8

simple partial seizure

type of focal/partial seizure

  • manifestation related to brain region involved
  • may be an aura
  • no alteration of awareness
  • may progress into a CPS or GTC seizure
  • post-ictal deficit maybe seen

9

complex partial seizure

typical presentaiton: staring and alteration of awareness

  • possible gaze deviation, forced head deviation, or unilateral/asymmetric limb involvement
  • possible automatisms
  • might progress into GTC seizure
  • might see post-ictal deficit

often no recal of most of event

 

EARLIEST manifestation helps localize the source brain region

10

secondary generalized seizure

seizure activity beginning in one part of brain that spreads to involve the rest

transition may be slow over minutes OR fast and appear "generalized" at onset

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symptomatic causes of seizure: categories

  1. metabolic-toxic
  2. structural
  3. benign
  4. genetic
  5. abnormal substrate
  6. rare causes

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symptomatic causes

 

metabolic toxic seizure

  • electrolyte imbalance
  • ingestion
  • medication-induced
  • rapid withdrawal

13

symptomatic causes

 

structural

  • head trauma
  • stroke
  • anoxia
  • meningitis/encephalitis
  • tumor
  • brain malformation (AVM, cortical dysplasia)

14

symptomatic causes

 

benign

  • fever(children)
  • post syncopal
  • contact

15

symptomatic causes

 

abnormal substrate

  • autism
  • other genetic disorder

16

symptomatic causes

 

rare causes

  • inflammatory
  • degenerative
  • inborn error of metabolism

17

mechanism of seizure

 

forces involved

concept of seizure threshold - how?

excitation

  • ionic currents: Na, Ca INWARDS
  • nt: glu, asp

inhibition

  • ionic currents: Cl INWARD, K OUTWARD
  • nt: GABA

 

in seizure, excitation >> inhibition

  • excitability to the extent that a seizure is produced occurs due to reduced seizure threshold

how?

  1. hypersynchronization (synaptic connectivity leading to propagation)
  2. inability to self-terminate (failure of negative feedback or feed-forward loop)
  3. changes in extracellular environment
  4. synapse chanel remodeling → permanency!

18

mechanism of genetic epilepsies

genetic epilepsies code for proteins in ion channels

→ ion flow is affected (overexcitable or low inhibition)

19

parts of the brain that are particularly prone to seizing activity

cerebral cortex and hippocampus particularly prone to synchronized bursts of activity

  • strong recurrent excitatory connections
  • intrinsically burst-generating neurons
  • ephaptic interactions among closely spaced neurons
  • synaptic plasticity

20

epilepsy

disorder of the brain that results in seizures that are:

  1. recurrent
  2. unprovoked
  3. stereotyped

21

seizure etiology

 

(classification)

1. idiopathic → genetic

2. symptomatic → structural/metabolic

3. cryptogenic → unknown

22

idiopathic seizures

  • genetic in nature without brain insult
  • probably polygenic inheritance

 

ex. benign epilepsy with centrotemporal spikes, childhood absence epilepsy

 

23

symptomatic seizures

clear/known brain insult causes seizures

 

ex. metabolic-toxic, fever, head injury, tumor, meningo-enceph, pre/perinatal ischemic/anoxic injury, neuronal migration defect

24

cryptogenic seizures

no evidence of a known brain insult or documented testing abnormality

 

  • test for: metabolic, radiologic, genetic evals
  • usually see degeneration, progression, regression
  • ex. infantile spasms

25

genetics of seizures

most often polygenic and multifactorial

  • single gene can cause epilepsy syndrome
  • single gene can cause multiple syndromes or non-seizure disorders (ex. movement disorders)
  • diff genes (monogenic), may cause a single epilepsy syndrome

 

typically involve ion channels: Na, Ca, GABA, K

26

localization of seizures and effects seen

 

  • temporal: medial vs lateral
  • frontal: dorsofrontal, SMA, orbitofrontal
  • parietal
  • occipital

temporal

  • medial: staring, automatism, posturing, fear
  • lateral: staring, vertigo, hearing

frontal: brief, bizarre, nocturnal

  • dorsolateral: contralateral vision
  • SMA: fencing posture
  • orbitofrontal: elaborate, sounds, smells

parietal: sensory

occipital: formed visual phenomena

27

EEG

measures electrical activity over scalp generated by the cortex

  • captures wakefulness, drowsiness, stage2 sleep 
    • epileptiform activity commonly activated in stage2 sleep

28

when would you get an MRI of brain?

patients with evidence of focality in seizures

  • looking for underlying structural lesion (encephalomalacia, cortical dysplasia, stroke, tumor, AVM, etc)

29

absence seizures

  • multiple events daily (could be > 100 daily)
  • usually 10s or less, triggered by hyperventilation, return to full awareness
    • often unnoticed
    • might have subtle automatisms during seizure
  • can contribute to poor academic performance

 

EEG: 3 Hz spike and wave

30

Lennox Gastaut

starts between infancy-14yo

  • most common in 2-3yr old
  • more in boys

multiple seizure types seen

  • axial tonic
  • atonic
  • atypical absence

cognitive impairment or regression

 

EEG: slow spike and wave, GPFA seizures

tx: tough to control 

31

infantile spasms

 

when/who?

symptoms?

EEG

tx?

onset: 3-18months

  • children with trisomy 21 or tuberous sclerosis more susceptible

characteristics

flexor, extensor, or combo events in clusters around sleep-wake transition

West syndrome: combo of spasms, hyparrhythmia, devpt regression

 

EEG shows hypsarrythmia: chaotic, high ampl, multifocal apikes, electrodecrement

 

idiopathic, symptomatic, or cryptogenic

 

 

 

tx: ACTH, vigabatrin, steroids, ketogenic diet

32

benign rolandic epilepsy

most common type of childhood epilepsy

ages 4-15, most commonly 7yo

symptoms

  • nightime focal onset or rapid secondary generalized seizure
  • speech arrest, drooling, gurgling, facial tonic-clonic activity, facial hemisensory
  • infrequent seizures
  • cognitive problems (often with language)

 

EEG: bilateral independent centrotemporal spikes

 

good outcomes! likely to outgrow, so practitioners might choose not to treat

  • if do treat, treat following second seizure

33

Wada test

  • injection of anesthetic into R or L internal carotid artery
  • test each hemisphere for memory and language

34

status epilepticus

one continuous seizure > 30 min

OR

recurrent seizures without regaining consciousness between seizures for over 30 min

35

acute management of status epilepticus

1. ABCs

2. IV lorazepam or diazepam

3. fosphenytoin

4. phenobarbital or valproic acid

5. versed drip or pentobarbital coma

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