Term
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Definition
a single episode of altered behavior or sensorium (perception) caused by excessive or hypersynchronous discharge of neurons
too many neurons being active can cause the brain to do/perceive something |
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Term
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Definition
an enduring predisposition to generate seizures (and actual occurrence of at least one seizure)
something wrong with the brain that predisposes it to seizures |
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Term
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Definition
a subjective abnormality experienced by some patients at the onset of a seizure, not associated with objective clinical signs
the first part of a seizure; always at the beginning, before clinical signs |
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Term
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Definition
coordinated, stereotyped, involuntary motor activity that would be purposeful if the patient were aware of it
NOT purposeful
usually a fairly-simple movement: lip smacking, chewing, swallowing, eating, hand wringing, picking at clothes, rearranging objects, verbalization of short stereotyped phrases, walking in circles |
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Term
| classification of seizures |
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Definition
first classified based on onset
-focal vs. generalized
then further classified |
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Term
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Definition
the first clinical and EEG changes indicate initial activation of a system of neurons limited to part of ONE cerebral hemisphere
the abnormal activity STARTS in one part of one cerebral hemisphere (may may spread to involve whole brain) |
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Term
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Definition
the first clinical EEG changes indicate initial involvement in BOTH hemispheres; started in whole brain at once
could be something systemic that affects entire brian at once
could be a focus so deep (ex: thalamus) that it spreads to the rest of the brain simultaneously |
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Term
| different ways focal/partial seizures can spread |
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Definition
locally
regionally (Jacksonian march)
bilaterally |
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Term
| local spread of partial seizure |
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Definition
| becomes more intense of a specific symptom |
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Term
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Definition
regional spread of partial seizure across the motor cortex
motor activity spreads from one body part to adjacent body part, progressively involving entire one side of body |
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Term
| bilateral spread of focal/partial seizure |
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Definition
spread to involve regions in the contralateral hemisphere and result in impaired consciousness = "complex partial seizure"
spread to other hemisphere through limbic system
generalized tonic-clonic movements |
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Term
| focal/partial seizure manifestations |
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Definition
a function of seizure focus
motor
sensory
autonomic (sense of rising discomfort)
emotional or psychotic (fear, pleasure, deja vu) |
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Term
| simple vs. complex partial seizure |
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Definition
simple: focal/part seizures in which consciousness is maintained
complex: in any of the focal/partial manifestations then spread to the limbic system so that the patient can't respond to normal environment; impaired consciousness |
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Term
| types of generalized seizures |
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Definition
absence
myoclonic
clonic
tonic
tonic-clonic
atonic |
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Term
| generalized absence seizure |
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Definition
tends to happens in kids
staring for a few seconds (brief)
may have eye blinking, lip smacking |
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Term
| generalized myoclonic seizure |
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Definition
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Term
| generalized clonic seizure |
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Definition
| rhythmic/repetitive jerking |
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Term
| generalized tonic seizure |
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Definition
stiffening
sustained contractions |
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Term
| generalized tonic-clonic seizure |
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Definition
(gran mal)
stiffening --> jerking |
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Term
| generalized atonic seizure |
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Definition
brief loss of muscle tone
collapse |
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Term
| classification of epilepsy |
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Definition
4 categories based on:
idiopathic vs. symptomatic
generalized vs. localization-realted (focal) |
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Term
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Definition
"cause unto itself"
a distinctive, well defined syndrome with known (or likely) genetic cause
not due to something else; no environmental trigger |
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Term
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Definition
symptom of a known or suspected CNS abnormality
(hypoxia, hypotension, GSW to head) |
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Term
childhood absence epilepsy
idiopathic generalized epilepsy |
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Definition
inherit to genetic make up of the child
onset between ages 4 - 8
spells begin suddenly - blank stare, interruption of ongoing activity
make be provoked by hyperventilation |
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Term
childhood absence epilepsy
management |
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Definition
1o rx: ethosuximide
2o rx: valproic acid, lamotrigine, clonazepam
generally a benign diagnosis, more than 2/3 of cases will resolve by teen years (and they can come off the drugs) |
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Term
juvenile myoclonic epilepsy
idiopathic generalized epilepsy |
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Definition
later onset, 12 - 14 years
generalized tonic-clonic seizures; myoclonic jerks may begin a year or more before (usually occur shortly after awakening)
responsive to valproic acid -- taken for life; dose not go away |
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Term
benign rolandic epilepsy
idiopathic localization-related epilepsy |
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Definition
onset between ages 5 - 10 years; usually resolves by teen years
seizures typically begin with hemi-facial twitching, drooling
occur primarily at night
very responsive to treatment (and AED used for partial seizures) |
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Term
mesial temporal sclerosis
symptomatic localization-related epilepsy |
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Definition
simple partial or complex seizures
often have a hx of febrile seizures, then long seizure-free interval (may be something during the febrile illness that set off the process)
EEG/MRI show mesial temporal abnormalities/sclerosis
response to meds varies, some may requires anterior temporal resection surgery |
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Term
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Definition
(not well understood)
2 key conditions requried:
-excessive neuronal excitability
-a pattern of synaptic connections between neurons that permit hypersynchrony |
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Term
| processes contribution to seizure pathogenesis |
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Definition
activity of voltage-gated ion channels
distribution and activity of inhibitory synapses (mainly GABA-ergic)
distribution and activity of excitatory synapses (especially glutamatergic)
any pathology in the brain can be a nidus for seizures to form |
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Term
| mesial temporal sclerosis |
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Definition
pathologic abnormality associated with seizures
mossy fibers of hippocampus sprout collateral fibers which could serve as a substrate for recurrent excitatory circuit
may relate to the role of the hippocampus in plasticity and memory (similar sprouting has been implicated in new memory formation)
seizures themselves may induce collateral sprouting
marked neuronal loss in CA1 region of hippocampus |
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Term
| pathologic abnormality associated with generalized epilepsy |
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Definition
pre-existing thalamocortical circuits are probably important
abnormal cortical development is an important pathologic substrate
-polymicrogyria (multiple tiny gyri)
-pachygyrai (thick gyri)
-schizencephaly (cleavage plains) |
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Term
| differential diagnosis of seizures |
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Definition
syncope
movement disiorders
sleep disorders (parasomnias, REM sleep behavior disturbance, PLMs)
TIAs
migraines |
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Term
differentiation between seizure and:
syncope |
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Definition
syncope usually has a warning of light-headedness, often precipitated by sudden standing or sudden emotion
a cardiovascular problem |
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Term
differentiation between seizure and:
movement disorders |
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Definition
MDs are usually ongoing or of variable duration if they are episodic
seizures are usually NOT episodic and not as stereotyped |
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Term
differentiation between seizure and:
sleep disorders |
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Definition
| sleep disorders occur in a specific stage of sleep |
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Term
differentiation between seizure and:
TIA |
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Definition
TIAs usually correlate to NEGATIVE symptoms
seizures usually correlate with POSITIVE symptoms |
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Term
differentiation between seizure and:
migraines |
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Definition
| migraines are for a longer duration and often accompanied by headache |
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Term
non-epileptic spells
("pseudo-seizures") |
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Definition
often less stereotypes, more variable; some patients have both
can be psychogenic
-often a sign of abuse
-psychological stressor/factor that can bring them on |
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Term
| characteristics suggestive of non-epileptic spell (vs. a true seizure) |
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Definition
-bilateral limb movements with PRESERVED consciousness
-asynchronous limb movements
-side to side head turning
-pelvic thrusting
-prolonged motionless unresponsiveness, with forced eye closure
-crying shortly after the spell |
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Term
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Definition
based on history (must ask lots of specific questions to learn how the spells start, progress, end, and if they are stereotyped)
EEG is the most helpful - but only if obtained during an actual spell (hard to do!)
EEGs tend to be abnormal between spells in only 1/2 of patients (but not specific) |
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Term
| approach to a single unprovoked seizure |
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Definition
look for provoking cause (head CT, metabolic, LP to look for infection)
treat cause if found - no AED tx needed
no AED recommended if cause not found; continue to monitor, remain untreated until sure of cause
NO driving |
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Term
| follow-up for single seizure episodes |
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Definition
MRI fu studies to look for subtle abnormalities that would put patient at risk for epilepsy
EEG (outpatient) to look for findings typical of interictal EEG in patients with epilepsy
-->looking to see if there is any predisposition to seizures/epilepsy |
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Term
| approach to second seizure |
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Definition
if patient had another seizure: start an AED (antiepileptic drug)
many options, some noteable rx's:
-phenytoin
-carbamazepine
-valproate
-gabapentic
-pregabalin
-lamotrigine
-topiramate
-levetiracetam |
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Term
| general points about seizure medications |
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Definition
all AEDs can cause:
-sleepiness, dizziness, ataxia, nausea, diplopia, headache
every AED has its own little quirks |
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Term
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Definition
*complex kinetics and many DDIs*
*cosmetic SE*
-gingival hyperplasia, hirsutism, rash, osteoporosis, cerebellar damage with long term use
~90% protein bound; hepatic microsomal metabolism
big jump in [serum] as you approach therapeutic ranges |
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Term
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Definition
*neutropenia*, hyponatremia, rash , osteoporosis
*DDIs* (erythromycin reduces clearance - potential toxicity) |
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Term
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Definition
*CP450 inhibtior*
*DDIs*
*weight gain*
*tremor*
*thrombocytopenia*
pancreatitis, hyperammonemia |
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Term
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Definition
*no DDIs*
one of the best tolerated, but not as effective as others
*weight gain, peripheral edema* |
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Term
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Definition
*no DDIs*
maybe works a little better than gabapentin - also well tolerated by not super effective
*weight gain, peripheral edema* |
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Term
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Definition
*broad spectrum*
seems to be very potent w/o a ton of SE
*slow to load (esp. in patients already taking valproate)*
*rash* (very RARE, but may be life threatening; must start slow and build up gradually on dose) |
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Term
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Definition
*weight loss*
*kidney stones, cognitive slowing/word-finding difficulty*
metabolic acidosis, glaucoma |
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Term
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Definition
*broad spectrum, no DDIs*
behavioral problems, rare psychosis
works! and typically well tolerated |
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Term
principles of medical epilepsy management:
when/what to prescribe |
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Definition
med not prescribed until a patient has had more than one seizure
choice of med based on type of seizure an patient's likely ability to tolerate particular meds |
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Term
principles of medical epilepsy management:
dosage |
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Definition
| dosage gradually increased as necessary until the patient is NOT having seizures, unless intolerable SE occur |
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Term
principles of medical epilepsy management:
failure of 1st medication |
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Definition
if seizures not controlled on max tolerated dose - add 2nd AED
taper 1st drug if seizures are controlled
trial and error, repeat as necessary with 3rd AED |
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Term
principles of medical epilepsy management:
when all drugs fail... |
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Definition
about 1/4 of epilepsy patients have seizures that cannot be fully controlled with meds
-reassess diagnosis
-consider surgical management
both of these may involve admission for long-term EEG and closed circuit TV monitoring |
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Term
| epilepsy surgery requirements |
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Definition
~1/2 of patients with partial seizures that cannot be controlled with meds may be candidate for surgical resection of the seizure focus
-spells must be epileptic
-seizures must be focal/partial and all have the same focus
-focus must be in a region of brain that can be safely removed |
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Term
| epilepsy post-surgical resection |
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Definition
~70% are seizure-free after surgery and some are able to come off of meds
most of the remainder have less frequent seizures |
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Term
| non-surgical options for resecting seizure focus |
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Definition
vagus nerve stimulation
ketogenic diet |
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Term
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Definition
stimulator placed in body (below clavicle) and lead connected to vagus nerve
provides intermittent stimulation (30s on, 5m off) to vagus nerve
mechanism unknown
about 30-50% of patients have significant reduction in seizure frequency; about equal to AED efficacy (but w/o systemic SE) |
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Term
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Definition
high-fat, adequate-protein, low-carb can produce a significant reduction in seizure frequency
mechanism unknown; compliance is difficult
common SE: constipation and GERD |
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Term
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Definition
seizures persisting more than 5 minutes are likely to continue; very dangerous to brain
mortality ~20% and requires urgent treatment
overt seizure activity (motor manifestations) may die out after a while, however if the patient doesn't return to baseline, get EEG to be sure patient is not in subclinical status |
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Term
| mortality of status epilepticus |
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Definition
much of the danger is from what is causing it
anoxia > hemorrhange > tumor > metabolic > infection > stroke > trauma > AED w/d > ETOH |
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Term
status epilepticus
treatment |
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Definition
important to establish and protocol and stick with it so don't have think about want to do in the moment
1. ABC
2. IV lorazepam (has rapid action)
3. IV fosphenytoin/phenytoin
4. more fosph is still seizing
5. add another agent, but need considering inducing coma (phenobarbital - suppress all brain activity) |
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Term
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Definition
no AED is considered to be 100% non-teratogenic (valproate is the worst)
seizures are worse for developing baby than AEDs
in treating pregnancy, use an AED if needed but try to limit to just one at the lowest effective dose and follow/monitor/adjust to keep free serum levels constant; avoid valproate
sexually active women of child bearing age should take folic acid to reduce risk of teratogenicity if they become preggers |
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Term
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Definition
in some patients who have gone for a length of time with no seizures, the seizure focus may resolve (patient looses intrinsic machinery to have seizures)
no test can reliably determine if this has happened, so patients must realize that this is a gamble (but often one worth taking with close physician supervision)
usually require 2-5 years of seizure-free activity |
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