Epilepsy & EEG Flashcards
What are the three definitions of epilepsy?
- At least two unprovoked seizures more than 24 hrs apart
- One unprovoked seizure + probability of another (EEG records and real time brain waves recorded)
- At least two seizures in setting of reflex epilepsy
How does epilepsy differ from a seizure?
In epilepsy there is an enduring predisposition to generate epileptic seizures–> neurobiological, cognitive, psychological, social consequences
A simple seizure is paroxysmal and transient
Generalized seizures
Starts on both sides:
Originates within and rapidly involves bilaterally distributed networks (cortical and subcortical)
Focal seizures:
Originated from network restricted to one hemisphere; may be discrete or wider distribution
How are EEGs useful?
Distinguish between focal or generalized seizure
What are the uses for continuous video EEG? (2)
- Distinguish between epilepsy and non-epileptiform events
- Rule out subclinical seizure in critically ill patients
How is seizure treatment customized?
Based on ONSET not spread
What are the shortcomings of 30 minute outpatient EEG?
- Limited sleep state (jaw muscle artifact)
- Misses some frontal lobe seizures
What is the ideal method to get maximum yield from an EEG?
- Done within 24-48 hrs of seizure
- Sleep deprivation and recorded sleep state
What is the proper method for placing EEG leads?
10%-10% of patient’s measurement and placement of leads accordingly; as long as head shape doesn’t change due to trauma or suture bulging, as long as you follow the system the leads will be put in the same place
Scalp location is surrogate for brain location
What are the Hz values for Alpha, beta, delta, and gamma waves
8-12 Hz = alpha
13+ Hz = beta
4-6 Hz= Delta
1-4 Hz= gamma
How do eye blinks appear on EEG? What is “Bell’s phenomenon”?
Negative vector is up, positive is down
Eye blinks are the cornea with a humongously positively charge touching the frontal region = “Bells phenomenon” causes the downward dip on EEG due to cornea rolling
Which leads change with maturity?
Occipital leads– you will see a posterior dominant background
What will you see with hyperventilation on EEG?
Diffuse slowing throughout all leads.
Caused by dip in CO2
**Note that if you saw focal slowing, you’d think focal brain lesion
In terms of spike and wave activity, what constitutes a seizure?
Lasts longer than ten seconds
What are the three types of focal seizures?
- simple partial (no LOC)
- complex partial (LOC / awareness)
- secondary generalization (w bilateral convulsions)
What are the 4 types of generalized seizures?
- Absence
- Myoclonic
- Tonic-Clonic
- Atonic
What are the typical EEG findings associated with generalized absence seizures?
What is a primary characteristic of absence epilepsy?
3 hz spike and wave discharge, generalized absence seizure
**No postectal confusion
What are the 4 classifications for epilepsy etiology?
- Genetic (especially frontal lobe)
- Structural/ metabolic (DKA, Hypernatremia)
- Unknown
- Immune/ Inflammatory mediated
Neonatal epilepsy is commonly caused by…
Benign familial neonatal epilepsy
What are two common causes of infantile seizures?
West syndrome
Dravet Syndrome
What is Benign Epilepsy with centrotemporal spikes?
At what age does it manifest?
What are the clinical features?
“Rolondic epilepsy”
Manifests after 1 yoa with twitching mouth and drooling
What are infantile spasms? What is the triad?
- EEG Hipsarrythmia
- Spasms
- Arrested psychomotor development
6 potential causes of infantile spasms:
- Malformations
- TS
- Chromosomal abnormalities
- Genetic mutations
- Inborn error of metabolism
- Hypoxic ischemic encephalopathy
What are the EEG features of Juvenile Myoclonic Epilepsy?
How does it present?
Not typical 3 Hz and spikes; 4-5 Hz
More clumsy in the morning; you need to ask about this and people may not complain.
What type of brain imaging would we order to assess heterotopia or mescal temporal sclerosis?
MRI with thin cuts +/- Gad protocol
At what age should we repeat MRI to ensure we see cortical lesions?
In all kids 2 and under; repeat after 1 year
What are the chances of having a second seizure in patients who have a single unprovoked seizure?
30-50% in 2-5 years
** ^ likelihood w EEG abnormalities or known etiology (Stroke, anatomical anomalies, etc)
Define treatment resistant epilepsy:
Failure of two well tolerated, appropriately chosen AEDs, used in appropriate schedule to achieve seizure freedom
What are some of the common ADRs associated with AEDs? (3)
- Drowsiness/ fatigue
- Dizziness
- Teratogenicity
**More meds = More ADRs
What are the meds used to treat focal and generalized seizures? (5)
- Valproate
- Lamotrigine
- Levetiracetam
- Topiramate
- Phenobarbital
Which is the most rash provoking AED?
Lamotrigine; can not load the drug–will cause SJS
What is the DOC for preggos w seizures?
Lamotrigine
Which drugs can be given IV and PO? (3)
- Valproate
- Levetiracetam
- Phenobarbital
What are some of the ADRs for Valproate? (2)
- CYP inhibitor; ^ Warfarin!!!
- Induces HPA axis–> weight gain–> PCOS
What is the notible ADR associated with Levetiracetam?
irritable mood
What are the ADRs associated with topirimate? (4)
- Weight loss
- Renal stones
- Poor cognition
- Teratogenic
***Takes 3 days to load
Which drug treats status epilepticus?
Is it an enzyme inducer or inhibitor?
- Phenobarbital (use IV fosphenytoin second line)
- INDUCES CYPS–> Decreases warfarin
What is catamenial epilepsy?
Seizure frequency increases during certain phases of menstrual cycle
What are some clinical pearls related wot women with epilepsy?
- Menopause?
- Estrogen?
- Etc?
- Earlier menopause
- Estrogen lowers seizure threshold (contraceptives…)
- ^ Infertility, decreased libido, PCOS
- Poor bone health (enzyme inducing AEDs)
Define status epilepticus:
- 5+ yoa
- 5 minutes of ictal activity w/ 2+ seizures between which there is incomplete recovery of consciousness
Non convulsive staus epilepticus: How do we ID this?
When should it be suspected?
- EEG only
- Suspect in patients w unexplained AMS or failure to regain consciousness 30 min after cessation of clinical seizures
