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57 Cards in this Set
- Front
- Back
What is an Epileptic Seizure?
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Abnormal PATTERN of cerebral neuronal rapid firing.
Sudden Onset Sudden Cessation Rapid Firing may cause abnormal behavior Can have subclinical seizures |
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What is a Non-Epileptic Event?
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Behavioral features are like a epileptic seizure
Event NOT due to rapid neural firing |
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Examples of Non-Epileptic Events?
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Pseudoseizure (conversion disorder)
Syncope |
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What is Epilepsy?
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Intrinsic predilection to recurrent seizures
Seizures not due to transient or reversible medical disorder Requires meds or surgery |
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Epilepsy Etiologies
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Genetic Disorders
Developmental Cortical Malformation Brain Infection Birth Injury Brain Trauma Brain Tumor Stroke |
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Difference between Symptomatic and Cryptogenic Epilepsy?
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Symptomatic: known cause
Cryptogenic: unknown cause |
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What is idiopathic epilepsy?
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NOT UNKNOWN CAUSE
The cause is presumed to be genetic w/ characteristic: Age of Onset EEG pattern Seizure Type |
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Causes of Seizures w/o Epilepsy?
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Electrolyte Disorder
Uremia Drug Intoxication Alcohol/Drug Withdrawal TRANSIENT/REVERSIBLE |
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What is a Convulsive Seizure?
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Seizure w/:
Stiffening or Jerking Involves face, limbs, or trunk |
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What is a Non-Convulsive Seizure?
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Seizure w/o stiffening or jerking
May have blank stare, unresponsiveness, or confusion |
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What is a Partial Seizure?
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Seizure involving part of cerebral hemisphere.
Typically confined to one lobe |
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What is a Generalized Seizure?
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Involves both hemispheres
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What is a Simple Partial Seizure?
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Partial Seizure w/o impairment of consciousness
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What is a Complex Partial Seizure?
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Partial Seizure with impairment of consciousness
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What is the difference between a Primary and a Secondary Generalized Seizure?
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Primary begins generalized.
Secondary begins partial and spreads |
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What is a seizure aura?
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The earliest conscious awareness of a seizure.
The aura is a simple, partial seizure. Sx's of aura reflect impairment of brain region at or close to seizure onset |
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What are Automatisms? types?
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Repetitive movements that occur during seizures.
Oral: lip smacking, chewing, swallowing Manual: picking, fumbling, patting |
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What is Impaired Consciousness?
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Inability to respond to others
Inability to follow commands Failure to make eye contact Impaired Memory Automatisms are common |
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what are the most common epicenters for seizures?
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1. Temporal
2. Frontal |
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Where does the Deja Vu feeling come from in our brain?
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Medial Temporal
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What is PDS and what is its significance?
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Paroxysmal Depolarization Shift
Electrophysiological Abnormality of PARTIAL epilepsy |
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What exactly is PDS?
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50-200msec depolarizatoin w/ superimposed repetitive spikes in ALL neurons of epileptic zone
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PDS in relation to:
1. EPSP |
1. PDS is more prolonged than EPSP
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PDS in relation to:
2. AMPA |
AMPA receptors trigger PDS
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PDS in relation to:
3. NMDA |
NMDA receptors mediate PDS
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PDS in relation to:
4. GABA |
GABA mediates post-PDS hyperpolarization
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What happens with PDS to cause a seizure?
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If PDS fails to terminate promptly, you get a seizure
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What is TLE?
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Temporal Lobe Epilepsy
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What is the most common pathology of TLE?
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Mesial Temporal Sclerosis
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What are other common pathological findings of TLE
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-hippocampal neuronal loss greatest in CA1 and least in CA2
-Prominent mossy cell neuron loss in the dentate hilus -Loss of mossy cell input to Inhibitory GABA basket cell interneurons causes them to go dormant. -Loss of Inhibition-->rapid firing -Shrunken Hippo |
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What's that pathogenesis called?
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The Dormant Basket Cell Hypothesis
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If the DBC hypothesis is correct, what should be effective Rx's?
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GABA enhancing drugs
Glutamate Attenuating Drugs Drugs that reduce maximum neural firing Surgical Resection of medial temporal lobe |
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Absence Seizures
Induced by? |
Hyperventilation
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Absence Seizures
duration? |
Brief: ~10 seconds
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Absence Seizures
how often? |
many per day (100/day)
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Absence Seizures
what happens after the seizure? |
they return to normal immediately
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Absence Seizures
etiology? |
GENETIC
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Absence Seizures
EEG? |
bilateral spike wave (2.5-4 Hz)
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Absence Seizures
Mechanism |
--Normally, thalamic relay neurons activate CTX bilaterally in rhythmic bursts during normal, non-REM sleep
--When these occur while you're awake...baddabing |
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What other players are there in Absence Seizures
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-Thalamic Reticular Neurons depolarize thalamic relay neurons and faciliate the burst
-T-type Ca channels and GABA receptors play some role |
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Rx for Absence Seizures
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Ethosuximide
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Ethosuximide
Mechanism? |
Acts on T-Type Ca Channels and blocks absence seizures
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What might be the cause of Early morning jerks?
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Juvenile Myoclonic Epilepsy (JME)
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What do JME and childhood absence seizures have in common?
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They're both forms of Primary Generalized Epilepsy
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Etiology of JME?
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Genetic Epilepsy Disorder
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When does JME start up?
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adolescence or young adulthood
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Types of seizures associated with JME
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Primary Generalized Convulsive
Myoclonic |
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How can you distinguish Primary from Secondary Generalized seizures?
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PRIMARY
Onset in childhood-->young adulthood No seizure aura No lateralized postural or clonic motor activities No post-seizure lateralized signs or symptoms EEG shows bilateral synchronous seizure related patterns MRI normal GENETIC! |
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Other Seizure Mechanisms
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Ion Channel Disorders (channelopathies)
Developmental Cortical Malformations |
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Types of Developmental Cortical Malformation?
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1. Abnormal connections between neurons
2. Abnormal neurons e.g. giant neurons of tuberous sclerosis |
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Types of Mutations leading to Channelopathies
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Na Channel
Potassium Channel |
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Cause of Na Channelopathy?
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STEPS
1. SCN1B mutation 2. defective Na channel subunit 3. action potential depol enhanced 4. enhanced bursts 5. generalized and febrile seizures |
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Cause of K channelopathy?
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1. KCNQ2 and 3 mutations
2. Defective K channel 3. K current decreased 4. neonatal convulsions occur |
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When do you initiate Rx for epilpesy?
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if there is a high risk of recurrent seizures
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When is there a high risk?
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2 or more spontaneous seizures
1 seizure and a progressive neurological disorder or an epileptic syndrome |
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Common Med SE's?
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1. Dose-related: cognitive impairment
2. Allergic/Immune mediated: rash, stevens-johnson 3. Drug Specific: lots 4. Teratogenic |
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What if meds don't work?
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SURGERY!
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