9/29 Seizures/Epilepsy - Bhise

Question 1

terminology:

ictal

post-ictal

interictal

Answer 1

ictal: during a seizure

post-ictal: immediately following seizure

interictal: time between seizures

Question 2

Todd’s paresis

Answer 2

post-ictal contralateral hemiparesis

Question 3

epileptiform

Answer 3

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

Question 4

seizure

Answer 4

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

Question 5

mapping old terminology to current terminology

grand mal

petit mal

Answer 5

grand mal → generalized

petit mal → focal/partial onset/absent

Question 6

seizure classification

two general types

multiple subtypes

Answer 6

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

Question 7

generalized tonic-clonic convulsion

Answer 7

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

Question 8

simple partial seizure

Answer 8

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

Question 9

complex partial seizure

Answer 9

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

Question 10

secondary generalized seizure

Answer 10

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

Question 11

symptomatic causes of seizure: categories

Answer 11

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

Question 12

symptomatic causes

metabolic toxic seizure

Answer 12

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

Question 13

symptomatic causes

structural

Answer 13

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

Question 14

symptomatic causes

benign

Answer 14

• fever(children)
• post syncopal
• contact

Question 15

symptomatic causes

abnormal substrate

Answer 15

• autism
• other genetic disorder

Question 16

symptomatic causes

rare causes

Answer 16

• inflammatory
• degenerative
• inborn error of metabolism

Question 17

mechanism of seizure

forces involved

concept of seizure threshold - how?

Answer 17

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!

Question 18

mechanism of genetic epilepsies

Answer 18

genetic epilepsies code for proteins in ion channels

→ ion flow is affected (overexcitable or low inhibition)

Question 19

parts of the brain that are particularly prone to seizing activity

Answer 19

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

Question 20

epilepsy

Answer 20

disorder of the brain that results in seizures that are:

1. recurrent
2. unprovoked
3. stereotyped

Question 21

seizure etiology

(classification)

Answer 21

1. idiopathic → genetic
2. symptomatic → structural/metabolic
3. cryptogenic → unknown

Question 22

idiopathic seizures

Answer 22

• genetic in nature without brain insult
• probably polygenic inheritance

ex. benign epilepsy with centrotemporal spikes, childhood absence epilepsy

Question 23

symptomatic seizures

Answer 23

clear/known brain insult causes seizures

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

Question 24

cryptogenic seizures

Answer 24

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

Question 25

genetics of seizures

Answer 25

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**

Question 26

localization of seizures and effects seen * temporal: medial vs lateral * frontal: dorsofrontal, SMA, orbitofrontal * parietal * occipital

Answer 26

**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

Question 27

EEG

Answer 27

measures electrical activity over scalp generated by the cortex * captures wakefulness, drowsiness, stage2 sleep * epileptiform activity commonly activated in stage2 sleep

Question 28

when would you get an MRI of brain?

Answer 28

patients with evidence of focality in seizures * looking for underlying structural lesion (encephalomalacia, cortical dysplasia, stroke, tumor, AVM, etc)

Question 29

absence seizures

Answer 29

* 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

Question 30

Lennox Gastaut

Answer 30

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

Question 31

infantile spasms when/who? symptoms? EEG tx?

Answer 31

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

Question 32

benign rolandic epilepsy

Answer 32

**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

Question 33

Wada test

Answer 33

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

Question 34

status epilepticus

Answer 34

one continuous seizure \> 30 min OR recurrent seizures without regaining consciousness between seizures for over 30 min

Question 35

acute management of status epilepticus

Answer 35

1. ABCs 2. IV lorazepam or diazepam 3. fosphenytoin 4. phenobarbital or valproic acid 5. versed drip or pentobarbital coma