Nervous System (Block 6): Seizures & Antiepileptics

Front 1

acute provoked seizure vs. single unprovoked seizure

Back 1

acute provoked - seizure event directly following a provoking event (ie. fever or trauma)

single unprovoked - seizure event that had no immediate provoking event for the seizure

Front 2

non-epileptic event vs. epilepsy

Back 2

epilepsy is defined as 2 or more seizures separated by more than 24 hrs.

non-epileptic event is anything that doesn't fit into that category

Front 3

define seizure

Back 3

paroxysmal, abnormal, excessive, hypersynchronous discharge of cortical neurons leading to change in behavior or EEG discharge
- can be "provoked" or "unprovoked"

Front 4

partial vs. generalized seizure

Back 4

partial - from one part of your brain (has a focal point) aka. "localization-related"

generallized- involves BOTH hemispheres of brain

Front 5

what do you call a seizure that started on one side of brain but then spread into both sides?

Back 5

"secondarily generalized"

Front 6

there are 2 types of partial seizures: simple vs. complex. define them!

Back 6

simple PS: no alteration of consciousness accompanies the seizure event

complex PS: seizure event if accompanied by impaired/altered, but not total loss of consciousness

Front 7

name some types of generalized seizures.

Back 7

clonic
tonic - stiffening
absence seizure -pt stops and stares
myoclonic seizure - quick contractions around a single joint
atonic seizure - pt loses tone (if moving, they'll just fall down)

Front 8

what type of seizures get pple in most trouble?

Back 8

frontal lobe epilepsies -seizures get pts into short, sometimes bizarre mvmts

Front 9

define infantile spasms

Back 9

body just does a mild spasm (ie. abdominal crunch). pt is otherwise nl, but spasms can cause loss of motor skills (usually go away on their own

Front 10

what are the 4 phases of seizure?

Back 10

1. aura = simple partial seizure (brief event that precedes clinical event, like smell, taste, fear, etc)
2. ictus - the "seizure" event
3. automatisms - semipurposeful automatic behaviors (ie picking at clothes, lip smacking)
- can happen in both partial or generalized epilepsies
4. postictal state - confusion, somnolence, fatigue that happens after ictal state (partial)
- aphasia (partial)
- focal weakness (partial)

Front 11

behavioral changes often refelcts anatomic location of abnormal discharge. describe:
- frontal lobe
- temporal
- parietal
- occipital

Back 11

FL - clonic mvmts, tonic posturing, atonia, bizarre bilateral hyperkinetic mvmts
TL - aura of smell, taste, emotion followed by confusion/staring
PL - somatosensory changes
OL- flashing light; visual distortion

Front 12

name 4 categories of underlying brain dysfunction that can lead to seizures:

Back 12

1. systemic (electrolyte changes, renal/liver failure)
2. cortical injury (acute: trauma, stroke vs. chronic: gliosis, neurodegeneration)
3. cellular/synaptic (cortical migration disorders, synaptic reorganization)
4. genetic abnormalities (ion channels, NT receptors, alot of pts with epilepsies inherit lots of abnormal ion channels that all contribute to epilepsy)

Front 13

one cause of seizures is the change in excitability. what happens?

Back 13

the inhibition:excitation ratio gets tilted in teh excitatioin direction and not making enough GABA leads to decreased inhibition

Front 14

another cause of seizures is a change in synchronization. name 3 possibilities

Back 14

- abnormal synapses (synapses go onto themselves or onto their neighbors to inc synaptic transmission)
- ephaptic transmission: field of one cell can excite another cell nearby
- glial fxn: having too many glial cells in parts of brain and they have something to do with synchronization

Front 15

define: epileptogenesis vs. latent period

Back 15

epileptogenesis = sequence of events leading to abnormal activity enough to convert nl neuronal network into hyperexcitable network

latent period = clinically silent period b/w initial injury and development of epilepsy

Front 16

_________ excitation and _________ synchronization predispose to seizures...

Back 16

Abnormal; excessive

Front 17

tell me the difference b/w symptomatic, idiopathic, and cryptogenic classifications as diagnostic causes for epilepsy

Back 17

symptomatic: evident cause (usually structural) for epilepsy - ie. cortical dysphasia

idiopathic: known or presumed genetic cause - ie. channelopathies

cryptogenic: "hidden cause" of seizures but with no known cause and with nl MRIs

Front 18

about 1/3 of pts with 1st seizures with normal EEG, MRI and exam will ________.

Back 18

NEVER have another seizure!

Front 19

over 90% of seizure pts with all three abnormal exams of EEG, MRI, and exams will ______./

Back 19

have another seizure

Front 20

for partial epilepsy, what is the 1st and 2nd line drug of choice? what are their mechanisms of action?

Back 20

1 - oxcarbazepine (dec volt gated Na channel conductance)
2 - levetiracetam (acts on synaptic vesicle protein SV2)

Front 21

broad vs. narrow spectrum. name an example of each.

Back 21

broad - agents with mult mechanisms and work for variety of seizure types (valproic acid)

narrow - selective mech of axn and works for only a few seizure types (ie. phenytoin)

Front 22

all anti-epileptics are metabolized by the _____ EXCEPT ______ (3).

Back 22

liver; gabapentin, pregabalin, levitiracetam

Front 23

what is the treatment of a 1st seizure?

Back 23

no daily Tx; just rectal diazepam (diastat) in case seizures recur

Front 24

how do antiepileptic drugs work?

Back 24

by restoring balance (dec excitation, inc inhibition, or both!)

Front 25

what are the common and serious SEs of oxcarbazepine?

Back 25

common - hyponatremia, ataxia, diplopia

serious - symptomatic hyponatremia

Front 26

what are common and serious SEs of levetiracetam?

Back 26

common - sleepiness, psychiatric disturbance

serious - none!

Front 27

which AED has the shortest half life?
which has the longest?

Back 27

gabapentin (5 hrs) - bad if ppl miss a dose, have to dose it several times a day

phenobarbital (100 hrs)

Front 28

all antiepileptics cause which 3 side effects?

Back 28

drowsiness, dizziness, rash (drugs acting on GABA tend to be more sedating)

"All antiepileptics won't be good for a DDR master"

Front 29

is there any AED that's entirely safe for pregnancy?

Back 29

no

Front 30

serious side effects of valproic acid, felbamate, carbazepine, phenytoin?

Back 30

acute hemorrhagic pancreatis, heptaic failure

aplasitc anemia

aplastic anemia

hepatotoxicity, aplastic anemia

Front 31

first and second choice of drug for generalized epilepsy -- absence seizures (include mech of axn)

Back 31

1 - ethosuximide (absence seizures only! dec voltage gated Ca channel conductane)
2- lamotrigine (dec conductance of Na channel)

Don't be absent or else you'll suck!

Front 32

what if pt has tried 2 drugs or more but to know avail -still has seizures? what 4 options are available?

Back 32

probably won't respond to med's anymore

- ketogenic diet
- epileptic surgery
- vagus nerve stimulator
- responsive focal cortical stimulation (experimental)