Oct4 A2-Seizures and Epilepsy

Question 1

anatomy of seizures

Answer 1

• originate in the cortex
• cortical neurons are arranged in 6 layers
• dz to cerebral cortex can cause seizures
• dz that damage other parts of the brain do NOT cause seizures
• stroke involving cortex = risk of seizures
• stroke involving brainstem or cerebellum = no risk of seizures

Question 2

seizures def

Answer 2

abnormal, COORDINATED, discharge of a group of neurons in the brain that has been allowed to continue unchecked
this group, region where it’s located = seizure focus

Question 3

when does a seizure lead to clinical symptoms

Answer 3

• the seizure focus spreads to adjacent neurons and neurons in other regions
• get clinical manif when area involved is large enough

Question 4

clinical manif of seizures

Answer 4

various combinations of transiently altered awareness or behavior in the patient

Question 5

common acquired causes of seizures

Answer 5

• strokes

- brain tumors

Question 6

principle of why seizure happens

Answer 6

• damage to inhibitory neuron (inhibit the excitatory neurons)
• leads to too much firing of excitatory neurons
• this damage to inhibitory neurons can be acquired (stroke, brain problem, metabolic effects, etc.)
• seizures can also have a genetic cause

Question 7

focal (partial) seizures def

Answer 7

• one group of seizures that ARE NOT GENETIC
• focal manifestations
• with or without impaired awareness (altered consciousness)
• manifestations depend on fct of cortical region of origin (or region to which epileptic activity spreads)

Question 8

focal seizure without impaired awareness is what (also called SIMPLE PARTIAL)

Answer 8

• abnormal mvmt
• can look at their mvmt, notice it’s happening
• can talk

Question 9

focal seizure with impaired awareness is what (also called COMPLEX PARTIAL)

Answer 9

• abnormal mvmt
• can’t talk
• can’t respond
• WITHOUT complete loss of consciousness

Question 10

consequence of focal (partial) seizure originating in the left motor cortex

Answer 10

get abnormal movements on the right side

Question 11

consequence of focal (partial) seizure originating in the parietal cortex

Answer 11

abnormal sensation

Question 12

types of cortical areas and resulting effects that you can get in seizures (type of symptoms)

Answer 12

• primary cortical areas (motor, sensory, auditory, visual)

- association cortical areas (for further processing of primary sensory data or the formulation of motor plans)

Question 13

what are generalized seizures

Answer 13

arise simultaneously from both hemispheres of the brain (NOT focal. something wrong with the whole brain)
-2 subtypes: primary and secondary generalized

Question 14

primary generalized seizure def

Answer 14

generalized at onset

Question 15

secondary generalized seizure

Answer 15

• begin as focal seizures

- then become generalized (epileptic activity spreads to involve both hemispheres)

Question 16

two common forms of generalized seizures + other one

Answer 16

• generalized tonic clonic seizures (grand mal seizures or big seizures)
• absence seizure (petit mal seizure)
• myoclonic seizures

Question 17

generalized tonic clonic seizures def

Answer 17

can be primary or secondary generalized tonic-clonic seizure
stereotypical progression
1. vocalization (loud cry)
2. tonic stiffening
3. clonic movements (jerky mvmts). steps 2 and 3 last 1-2 min
4. prolonged post-ictal period

Question 18

absence seizure (petit mal) def

Answer 18

• minimal motor manifestation (like lip smacking, slightly turning the head
• stop and stare for 5-10 seconds

Question 19

myoclonic seizure def

Answer 19

• a type of primary generalized seizure
• arises from both hemispheres
• the FINDINGS LOOK focal (sudden, brief, single jerk of one body part) but really, the jerks are seen bilaterally, in any body region, although not simultaneously)

Question 20

aura def

Answer 20

• subtle symptoms that a person may experience at onset of a PARTIAL seizure (focal)
• are PART OF THE ONSET of seizure of the seizure OR can exist alone
• odors, visual symptoms, rising sensations in the chest or abdomen, strong sense of déjà vu

Question 21

prodrome def

Answer 21

something that happens in HOURS or DAYS before a seizure that the patient relates to their seizures. ‘‘I knew I was going to have a seizure because…’’

• are usually more vague sx (fatigue, decreased concentration, etc.
• IS NOT part of the seizure

Question 22

in what dz do auras and prodromes also both exist (note: in epilepsy, auras are only in focal seizures)

Answer 22

migraine headaches

Question 23

complex partial seizure (focal with impaired awareness) vs absence (petit mal) seizure (generalized) clinically

Answer 23

can both look similar

• complex partial = not aware but conscious, eyes open, can be standing
• absence = eyes roll upwards, facial expression drops, still conscious

Question 24

absence seizure charact

Answer 24

• generalized

- usually genetic

Question 25

primary generalized tonic-clonic seizure possible cause

Answer 25

could be genetic epilepsy

Question 26

secondary generalized tonic-clonic seizure possible cause

Answer 26

something focally wrong with the bain (bc the seizure started as focal)

Question 27

steps to take care of pt with seizure

Answer 27

``` take care of pt -prevent from injuring themselves (recovery position, do not touch their mouth) -if >2 min or ANY doubt = call 911 describe the event -observe -note time of start and end -note responsiveness *not true that they can suffocate on their tongue* ```

Question 28

what is status epilepticus

Answer 28

a seizure activity that lasts continuously for >5 min - ONLY seizure type that is BAD for the brain is a PROLONGED GENERALIZED TONIC-CLONIC SEIZURE - needs emergency tx according to specific protocols * textbook def = continuous seizure activity for >30 min or recurrent seizure activity without regaining consciousness, for >30 min*

Question 29

what is epilepsy

Answer 29

occurence of two or more seizures in an individual, with the understanding that there is an ongoing risk of recurrence - last part is imp bc in certain circumstances (like low blood Na, hypoglycemia, extreme sleep deprivation, alcohol withdrawal), anyone can have seizures but if remove these circumstances, seizures should stop * epilepsy = risk of seizures without these factors*

Question 30

some factors that can provoke seizures in someone who doesn't have epilepsy (meaning no longer at risk of seizures if remove these factors)

Answer 30

- fever - acute injury - certain meds - alcohol withdrawal - certain metab problems like hyponatremia

Question 31

provoking factors of seizures in someone who has epilepsy

Answer 31

seizures are either - unprovoked - provoked by factors that DON'T cause normally provoke seizures in a healthy individual (like mild sleep deprivation and hyperventilation) + if you remove these abnormal provoking factors, pt still at risk of seizures

Question 32

what is an epileptic syndrome

Answer 32

classif of seizures based on combination from these two factors -localization related or generalized -genetic, structural/metabolic, unknown factors *many seizure types in each broad category FOR EXAMPLE: 1. generalized genetic 2. localization-related structural

Question 33

why classify pts in epileptic syndromes

Answer 33

it determines the tx and prognosis

Question 34

how to classify a pt in a a specific syndrome

Answer 34

use multiple info sources - age of onset - FHx - neuro exam - type of seizure (or types): possible to have many types in one pt - EEG and imaging findings

Question 35

(NOT ON EXAM) what epileptic syndrome in - onset in teens - FHx nothing - neuro exam normal - seizure type GTC

Answer 35

- juvenile myoclonic epilepsy, a form of generalized epilepsy with GTCs, myoclonic jerks and, sometimes, absence seizures - thought to be caused by a genetic mutation * so GENERALIZED GENETIC*

Question 36

(NOT ON EXAM) what epileptic syndrome in - onset in teens - FHx nothing - neuro exam normal - seizure type GTC with focal onset (pt describes an aura) - EEG focal epileptic activity in left temporal lobe - MRI could show mesial temporal sclerosis

Answer 36

- temporal lobe epilepsy, a form of localization-related epilepsy - known to be specifically a secondary generalized seizure bc of hx (aura and then generalized)

Question 37

(NOT ON EXAM) JME vs TLE

Answer 37

- TLE responds poorly to AEDs, surgery can be curative (focal onset) - JME responds very well to AEDs. good control with 1 AED

Question 38

spectrum of meds effect in epilepsy

Answer 38

goes from - compliant + seizure free with one med - 3-4 meds, some seizures happening, adverse effects of higher med doses + frustration bc meds don't work

Question 39

2 imp principles about EEGs

Answer 39

- can't rely on EEG to DIAGNOSE a seizure (don't know the cause of an LOC and want to know if was a seizure = CAN'T do that) - EEG is one of the defining features of an epileptic syndrome

Question 40

how EEG works

Answer 40

- records summated PSPs from neurons located in OUTER layers of the cerebral cortex - usually records interictal epileptic activity (a marker of seizure focus but is NOT a seizure) - may record ictal epileptic activity sometimes (an actual seizure)

Question 41

interictal epileptic activity charact

Answer 41

- EEG: certain groups of sharp looking waves with diff amplitudes (EEG looks pretty flat) - indicates there is a seizure focus (small group of neurons firing abnormally) - this abnormality is present enough to be detected on EEG but NOT enough to cause sx so NO SYMPTOMS

Question 42

ictal activity charact

Answer 42

- means seizure - EEG = continuous activity for multiple seconds, many spikes with huge amplitude, mechanisms in the brain eventually shut this down

Question 43

how do you DIAGNOSE seizures

Answer 43

clinically, with hx

Question 44

limitations of EEGs

Answer 44

- last 20 to 30 min so won't always catch epileptic activity and seizures bc these are paroxysmal events - EEG is normal in 50% of pts after first seizure (does not rule out seizures) - epileptic activity on EEG can be seen in normal people (can not dx that it is a seizure that happened)

Question 45

use of EEG in epilepsy

Answer 45

- help confirm the localization and classify the epileptic syndrome - in pts with GTC seizures, can tell if is generalized interictal epileptic activity (primary GTC seizures) or focal interictal epileptic activity (secondary GTC seizures)