Term
| prevalence of epilepsy in the US population? |
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Definition
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Term
| what is the risk of harm to self and others due to with epilepsy? |
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Definition
1. transient impairment of consciousness
2. unpredictable occurrence
3. abrupt loss of competence |
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Term
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Definition
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Term
| what is a transient alteration of behavior due to synchronous and high frequency firing of a large number of cortical neurons? |
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Definition
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Term
| what is the medical term for a seizure? |
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Definition
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Term
| what is the motor manifestation of a seizure? |
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Definition
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Term
| what is the periodic and unpredictable occurrence of seizures? |
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Definition
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Term
| where does a seizure originate? |
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Definition
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Term
| in grand mal seizure, the motor manifestations are ____ |
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Definition
| bilateral - both extremities, including the trunk |
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Term
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Definition
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Term
| where do seizures arise from? |
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Definition
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Term
| what determines the behavioral manifestations of seizures? |
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Definition
| the functional role of the cortical site of origin |
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Term
| is rhythmic contraction of muscles below the cortical level a seizure? |
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Definition
NO
must arise from the cerebral cortex |
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Term
| what is loss of consciousness in a seizure dependent on? |
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Definition
| spreading of the firing signal |
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Term
| what type of firing signal leads to no impairment of consciousness? |
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Definition
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Term
| what firing signal leads to impairment of consciousness with seizure? |
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Definition
| spreads from one network to another; even if it doesn't involve both hemispheres |
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Term
| what firing signal will lead to loss of consciousness with a seizure? |
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Definition
| bihemispheric generalized firing |
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Term
| what can give a preliminary diagnosis of type of seizure (localized or generalized)? |
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Definition
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Term
| what is the most common (60%) type of epilepsy? |
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Definition
| focal onset or partial seizures |
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Term
| what are the 3 subtypes of focal onset epilepsy? |
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Definition
1. local (simple partial)
2. complex partial
3. secondarily generalized |
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Term
| in what 2 areas of cortex can local (simple partial) seizures be located? |
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Definition
1. neocortex
2. hippocampal and parahippocampal |
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Term
| can local (simple partial) seizures spread? |
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Definition
| YES but the spreading is limited local spread, spreading around certain foci |
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Term
| what is seen in a local seizure of the neocortex without local spread? |
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Definition
clonus
myoclonus
inhibitory motor, sensory, aphasic |
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Term
| what is seen in a local seizure of the neocortex with local spread? |
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Definition
Jacksonian march
sensory experimental |
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Term
| what are the 2 types of propagation in complex partial subtype of focal onset epilepsy? |
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Definition
| ipsilateral and contralateral propagation |
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Term
| which type of propagation in complex partial subtype of focal onset epilepsy will lead to impairment of consciousness? |
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Definition
| ipsilateral propagation spread to the limbic system |
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Term
| characteristics of secondarily generalized focal onset epilepsy? |
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Definition
starts focal and spreads --> ends as generalized seizures
most serious type; what is understood by most as epilepsy |
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Term
| what are the 3 classes of epilepsy? |
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Definition
1. focal onset or partial seizures - 60%
2. generalized onset - 40%
3. unclassified |
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Term
| what is the origin and state of consciousness in generalized onset epilepsy? |
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Definition
bihemispheric origin
consciousness impaired - loss of consciousness |
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Term
| what are the 3 major forms of generalized seizures? |
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Definition
1. tonic-clonic (grand mal)
2. absence
3. myoclonic |
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Term
| what is characteristic of absence generalized onset seizures? |
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Definition
patient is unresponsive to the environment and then comes back
*convulsions are absent and consciousness is briefly lost |
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Term
| juvenile myoclonic epilepsy is what percentage of all epilepsy? |
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Definition
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Term
| how is myoclonic epilepsy different from myoclonic jerking when you fall asleep? |
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Definition
in epilepsy the jerking occurs while the patient is awake and not just when they are falling asleep
it is usually juvenile |
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Term
| what is status epilepticus? |
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Definition
1. continuous seizures for 5-15 min
2. recurrent seizures (up to 30 min)
3. no recovery of consciouness |
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Term
| what seizure types can status epilepticus develop from? |
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Definition
| any of the other seizure types |
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Term
| unclassified seizures include what? |
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Definition
neonatal seizures
symptomatic seizures (febrile, etc) that can progress to epilepsy |
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Term
| what is the etiology of tonic-clonic (secondarily generalized) seizures? |
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Definition
mutations in Na, K channels or N-cholinergic receptors
leads to rapid firing of AP |
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Term
| what is the etiology of absence seizures? |
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Definition
| mutations in T-type voltage gated Ca channels |
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Term
| what is seen on an EEG in absence seizures? |
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Definition
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Term
| what type of seizure produces characteristic 3 Hz spikes on EEG? |
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Definition
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Term
| what is the etiology of myoclonic (juvenile myoclonic) seizures? |
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Definition
MELAS - Mitochondrial Encephalopathy, Lactic Acidosis, Stroke; A3243G mutation in mtDNA
MERRF - Myoclonic Epilepsy, Ragged Red Fibers; G8344A mutation in mtDNA |
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Term
| symptomatic (organic) causes of epilepsy? |
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Definition
| irritation of neurons by: trauma, neoplasm, vascular, infections, degeneration, metabolic |
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Term
| what is the differential diagnosis for partial (focal seizures)? |
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Definition
TIA
rage attack
panic attack |
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Term
| what is the differential diagnosis for generalized seizures? |
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Definition
syncope
cardiac arrhythmia
brainstem ischemia
pseudo-seizures (hysteria, malingering) |
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Term
| synchronous and high frequency firing of a large number of cortical neurons causes? |
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Definition
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Term
| mechanisms of high frequency firing neurons in seizure (4)? |
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Definition
1. excitation prevails over inhibition
2. propagation of inter-neuronal signaling overrides signal isolation
3. firing synchronizer - for simultaneous output
4. persistent depolarization of cortical neurons |
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Term
| how does the balance of GABA and glutamate lead to seizures? |
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Definition
overproduction of glutamate --> increase excitability
loss of GABA --> loss of inhibition --> increased excitability
excitation prevails over inhibition |
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Term
| when is synchronization of firing neurons important? |
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Definition
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Term
| what neurons are involved in synchronization in seizures? |
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Definition
| thalamic neurons with T-type voltage gated Ca channels |
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Term
| persistent depolarization of cortical neurons is detected how on EEG? |
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Definition
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Term
| what is a depolarization shift of APs in seizures? |
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Definition
| threshold for a neuron remains at a less negative value - lowers threshold for firing and increases the rate of firing |
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Term
| what drug administration can lead to seizures? |
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Definition
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Term
| how does isoniazid lead to seizures? |
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Definition
| pyridoxine depletion (GABA synthesis co-factor) --> decreased GABA --> loss of inhibition --> seizures |
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Term
| in which type focal onset seizure is consciousness preserved? |
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Definition
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Term
| how does a local (simple) focal onset seizure manifest? |
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Definition
sudden jerking of an extremity for <90 sec followed by residual weakness for <30 min
patient is completely aware of attack and can describe it in detail
duration: 60-90 sec
*consciousness is preserved |
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Term
| how does a propagated (complex) focal onset seizure manifest? |
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Definition
brief warning, altered consciousness, staring, staggering, even falling
motor manifestations - automatism
gradual recovery after 2 min; tiredness for hours
duration: 30-120 sec |
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Term
| what is automatism and what type of seizure do you see it with? |
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Definition
purposeless movements - such as lip smacking, hand wringing, swallowing, walking, fumbling, scratching
seen in propagated (complex) focal onset seizures |
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Term
| what are the states of consciousness in the 3 types of focal onset seizures? |
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Definition
1. local - preserved consciousness
2. propagated - impaired consciousness
3. secondarily generalized - loss of consciousness |
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Term
| what are the durations of the 3 types of focal onset seizures? |
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Definition
1. local - 60-90 sec
2. propagated - 30-120 sec
3. secondarily generalized - 60-120 sec |
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Term
| why is consciousness impaired in propagated (complex) focal onset seizures? |
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Definition
| because it propagates to the limbic system |
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Term
| temporal lob epilepsy is a subtype of what classification? |
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Definition
| propagated focal onset seizures |
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Term
| how does a secondarily generalized focal onset seizure manifest? |
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Definition
focal seizure evolved into sustained contractions (tonic) of body muscles followed by rhythmic contraction/relaxation (clonic)
loss of consciousness
duration: 60-120 sec |
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Term
what is the maximum duration of a tonic-clonic generalized onset seizure?
what is it called if the seizure lasts longer than this time? |
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Definition
4 min
>5 min = status epilepticus |
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Term
| what is the state of consciousness in a tonic-clonic generalized onset seizure? |
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Definition
loss of consciousness
not preceded by a focal seizure |
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Term
| mnemonic for grand mal (tonic-clonic) seizures? |
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Definition
aura, cry, fall, fit
tonic, clonic, urine, shit |
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Term
| age of onset for absence (petit mal) seizures? |
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Definition
begins in childhood
ceases by age 20 |
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Term
| how does a absence (petit mal) generalized seizure manifest? |
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Definition
staring, cessation of ongoing activities
duration: usually <10 sec; rarely >45 sec
*abrupt onset of impaired consciousness; abrupt recovery |
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Term
| what is seen on EEG during an absence seizure? |
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Definition
| bilateral synchronous symmetric 3-Hz spikes |
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Term
| how does a myoclonic generalized onset seizure manifest? |
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Definition
shock-like contraction of muscles which may be restricted to one extremity or may be generalized
duration: <1 sec |
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Term
| what are the stages of grand mal seizure (9)? |
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Definition
1. +/- aura
2. cry
3. sudden loss of consciousness
4. fall
5. tonic
6. clonic
7. relaxation
8. flaccid coma
9. awakening |
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Term
| how long does the aura last in grand mal seizure? |
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Definition
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Term
| does every grand mal seizure have an aura? |
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Definition
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Term
| what are some manifestations of an aura in a grand mal seizure? |
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Definition
5 senses hallucination
dysmnesia - deja-vu or jamais-vu
visceral aura |
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Term
| why is an aura important before a grand mal seizure? |
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Definition
| its a warning sign and the patient can prepare for loss of consciousness, etc that is coming |
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Term
| why does a patient having a grand mal seizure 'cry'? |
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Definition
| diaphragm contraction causes forced expiration |
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Term
| how long is the tonic phase of a grand mal seizure and how does it manifest? |
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Definition
<1 min
muscles are held in a contracted state - body rigidity, arrest of respiration, tongue biting, incontinence, aspiration, other injury |
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Term
| what is a sign that points to grand mal epilepsy not seen in other forms of seizure? |
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Definition
incontinence
happens because the detrusor muscle contracts uncontrollably |
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Term
| how long is the clonic phase of grand mal seizure and how does it manifest? |
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Definition
<3 min
jerking; rhythmic contraction/relaxation of limbs |
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Term
| what is the duration of the flaccid coma in a grand mal seizure? |
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Definition
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Term
| what are some effects of a grand mal seizure after awakening? |
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Definition
retrograde amnesia
post-ictal confusion
post-epileptic automatism |
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Term
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Definition
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Term
| how is epilepsy diagnosed? |
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Definition
the seizure is unlikely to be observed directly by a physician
look for:
1. history of recurrent seizures with incontinence
2. postictal abnormalities on physical exam - focal neurological signs and mental status exams
3. EEG changes - 'interictal spike' |
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Term
| what is the major sign for diagnosing epilepsy? |
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Definition
| 'interictal spike' on EEG |
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Term
| what is an interictal spike? |
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Definition
| a sharp EEG waveform during symptomless period |
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Term
| what is paroxysmal depolarization shift (PDS)? |
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Definition
persistent depolarization of the neuronal membrane due to a burst of AP
seen on intracellular recording - see baseline increase in membrane potential |
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