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111 Cards in this Set
- Front
- Back
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Definition: seizure
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Sudden rhythmic change in cortical activity resulting form synchronous firing of cortical neurons
-may be accompanied by a behavior change or subjective sensation |
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Post ictal period
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period of lethargy or confusion after a seizure
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Focal seizure
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Seizure beginning in a local area in one hemisphere
aka partial seizure Eg: simple partial (no LOC) Complex partial (change in consciousness) Secondarily generalized seizure New naming system is more decriptive |
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Generalized seizure
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starts in both hemispheres simultaneously
eg: Absence Tonic-clonic tonic clonic myoclonic atonic |
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Generalized epilepsy
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Predisposition to generalized seizures
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Partial/focal epilepsy
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Predisposition to partial seizures
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Generalized tonic-clonic seizure
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"grand mal"
initial stiffening--> back and forth shaking |
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Tonic seizure
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just stiffening
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Clonic seizure
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just shaking
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Myoclonic seizure
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Brief jerking seizure
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Atonic seizure
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drop attack
brief loss of muscle tone |
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Absence seizure
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Petit mal
abrupt loss of awareness may have eye fluttering or automatisms |
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Simple partial seizure
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Focal seziure with no change in level of awareness
-may have aura (subjective symptoms) - may have focal clonic activity |
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Aura
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subjective symptoms/ sensations
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Focal motor seizure
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focal clonic activity
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Complex partial seizure
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Focal seizure with a change in the level of awareness
- preceded by aura - may secondarily generalize |
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Catgeories of seizure symptoms
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1) subjective/aura
2) motor 3) autonomic 4) cognitiion |
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Seizure semiology
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Classification system looking to accurately describe seizure signs
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Psychogenic/Pseudo-seizures
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Not a real seizure
signs it may be psychogenic: -tremor -arching back -drug seeking behavior - no loss of awareness |
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Status epilepticus
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Continual seizure activity
continual for >30 minutes and/or series without recovery between |
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Epilepsy
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Predisposition to unprovoked seizures
- 2 or more - spontaneous - predisposition--> it doesn't go away |
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Possible seizure provokers
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- Head trauma
- acute stroke - severe metabolic abnormality - drug/toxin ingestion - fever |
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Symptomatic epilepsy
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caused by a brain lesion; may be mentally reatarded
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Cryptogenic epilepsy
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Caused by a lesion that we can't find
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Idiopathic epilepsy
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seizures without a brain lesion; usually normal intelligence
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Exception to the rule that all focal seizures are symptomatic seizures
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- Benign rolandic epilepsy
- unilateral focal motor seizures in kids at night - resolves by puberty |
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EEG in epilepsy
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Spikes or sharp waves
- generalized if general epilepsy - focal if focal epilepsy |
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EEG in seizure
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Sudden rhtymic change that evolves over time
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Subclinical seizure
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Electrical EEG changes without alteration in behavior
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Electrophysiology of epileptiform spikes on EEG
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Product of large group of neurons firing synchronously--> large rapid negative extracellular potential followed by return to baseline
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Childhood absence epilepsy
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Idiopathic generalized epilepsy
onset: 4-8 Seizure type: absence provoke: hyperventilation intellect: normal EEG: 3 hz spike and wave Tx: Ethosuxamide; blocks thalamic t-type Ca2+ channels Resolution: puberty |
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Juvenile Myoclonic epilepsy
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Idiopathic generalized epilepsy
onset: 12-18 type: myoclonic--> GTC or absence provoking: waking up in AM intellect: normal EEG: 4-4.5 hz generalized spike and wave Tx: Valproate UNLESS woman of child bearing age--> levetiracetam; can be made WORSE by pheyntoin, carbamezepne, ocarbazepine, neurontin Resolution: no |
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Lennox-Gastaut syndrome
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Symptomatic generalized epilepsy
seizure type: GTC, myoclonic, absence, atonic, focal EEG: ? Tx: none |
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Benign Rolandic Epilepsy
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Idiopathic partial epilepsy (the only one)
Onset; 5-9 Seizure type: focal motor Provoke: night time Treatment: not necessary REsolution: by puberty |
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Mesial Temporal Lobe Epilepsy
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Symptomatic focal epilepsy
Seizure type: Focal seizures originating in hippocampus or amygdala Aura: Insular cortex--> nausea eeg: focal temporal spikes Tx: most can't be controlled medically; surgery may help Temporal neocortex--> deja vu Uncu--> olfactory hallucination amygdala--> sudden emotional feeling Association cortex--> perceptual distortions Insular cortex--> autonomic symptoms |
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Aura associated with insular cortex
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Rising epigastric sensation
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Aura associated with temporal neocortex
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Deja vu
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Aura associated with uncus
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olfactory hallucination
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Aura associated with amygdala
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sudden emotional feeling
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Aura associated with association cortex
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perceptual distortions
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Aura associated with insular cortex
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autonomic symptoms
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Automatism
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repetitive quasi-purposeful movemnts like:
lip smacking swallowing fumbling picking at clothes |
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Neocortical epilepsy
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Seizure: focal origin in the temporal neocortex or frontal lobe with rapid spread and generalization
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Frontal Lobe epilepsy
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Seizures: automatisms, noises, postures
Origin of seizure: frontal lobe Provoking: nighttime ** these patients may have preserved awareness |
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Supplementary motor area seizures
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** these seizures may look like psuedoseizures
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Causess of epilepsy
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- hippocampal sclerosis
- neoplasms - heterotopias - cortical dysplasia - vascular malformation |
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Gelastic seizure
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main motor manifestation is laughing; often due to hypothalamic hamartoma
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Versive seizure
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seizure where eyes, head, and torso move to one side; may be due to lesion in frontal eye field in the frontal lobes
- lateralizing feature |
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Mechanisms of seizure generation
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1) too much excitation--> too much Na+, Ca2+ current or too much Glutamate or Aspartate stimulation
2) too little inhibition--> two little inward Cl-, outward K+; or too little GABA transmission |
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Targets for anti-convulsant drugs (4)
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1) increase GABA
2) Decrease excitatory Glutamate 3) Block inward positive currents: Na+ or Ca2+ 4) Increase outward K+ current Pleotropic: act by multiple mechanisms |
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Felbate binding site
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NMDA receptor glycine binding site
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Benzodiazepine action at GABA receptor
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Increases frequence of GABA mediated chloride channel openings
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Barbiturate action at GABA receptor
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Prolongs duration of Cl- channel opening
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AEDs that act on NMDA receptor to decrease glutamatergic stimulation
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Felbamate
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AEDS that act on GABA
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Benzos: diazapam, clonazapam
Barbiturates: phenobarbital, primidone Gabapentine Tiagaine--> reuptake inhibitor Vigabatrin-->inhibits catabolism *** NOT PREGABALIN (lyrica) |
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AEDs that act on Sodium channels
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Phenytoin
Carbamazepine/Oxocarbazepine Lacosamide Zonisamide |
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AEDs that act on Ca2+ channels
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Ethosuxamide ONLY blocks t-type Ca2+ channel--> only for absence
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AEDs that act on K_ channels
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Valproate
Oxcarbazepne |
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Pleotropic AEDs
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Felbamate (NMDA, Na+)
Lamotrigine Topiramate Valproate: GABA, Na+, K+, Ca2+ |
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Valproate does it all
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- Ca2+ channel blockade
- Na2+ channel blockade - potentiation of GABA |
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Limitations of 1st generation AEDs
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- incomplete efficacy
- unfavorable kinetics as enzyme inudcers/inhibitors; high protein binding - narrow therapeutic range - CNS effects - drug interaction |
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1st generation enzyme inducers
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- Phenytoin
- Carbamazepine--> induces it's own metabolism! - Phenobarbital |
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1st generation enzyme inhibitors
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Valproate
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mechanism of phenytoin
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inhibition of Na+ channels
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Limitations of phenytoin
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- high protein binding/ enzyme saturation--> non-linear kinetics
- Adverse effects: CNS sedation--> acts like alcohol gum hyperplasia - hirsuitism |
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Uses of phenytoin
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EMERGENCY for Status Epilepticus
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Mechanism of Carbamazepine
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INihibition of Na+ channels
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Adverse effects of Carbamazepine
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-Agranulocytosis and aplastic anemia
-hyponatremia -stimulates metabolism of other drugs and itself! (tolerance) |
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Mechanism of phenobarbital
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Allosteric modulator of GABA receptor--> increases duration of opening
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Adverse effects of phenobarbital
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CNS depression
stimulation of hepatic metabolism |
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Mechanism of primidone
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allosteric modulator of GABA
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Uses of primidone
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PARTIAL SEIZURES
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USES OF PHENOBARBITAL
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PARTIAL SEIZURES
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Mechanism of benzos
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increased frequency of GABA channel oening
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Uses of benzos
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rescue medication in status eplepticus
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Adverse effects of benzos
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CNS sedation, tolerance, dependence, paradoxical hyperexcitability
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Mechanism of valproate (multiple
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- inhibition of NA+ channel
activation of K+ channel GABA enhancing inhibition of Ca2+ channel |
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adverse effects of valproate
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- hepatotoxicity
- birth defects: neural tube defects |
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uses of valproate
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all types of seizures including partial EXCEPT in young women of child bearing age
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mechanism of ethosuxamide
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inhibition of T type calcium channels
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adverse effects of ethosuxamide
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not too many
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Uses of ethosuxamide
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absence seizures ONLY
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Mechanism of oxocarbazepine
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same as carbamzepine: inhibition of Na+ channels
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adverse effects of oxcarbazepine
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hyponatremia
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Uses of oxcarbazepine
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partial seizures
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Mechanism of gabapentin
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interferes is GABA uptake
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Adverse effects of gabapentin
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weight gain
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Uses of gabapentin
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not great for seizures
great for neuropathic pain |
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mechanism of lamotrigine
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inhibition of Na+ channels and glutamate release; may inhibit Ca2+ channels
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Adverse effects of lamotrigine
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Steven johnson syndrome
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Uses of lamotrigine
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pregnancy for generalized and focal epilepsies
mood stabilization in bipolar disorder |
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mechanism of Felbamate
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inhibition of NMDA receptor via glycine binding site
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Adverse effects of felbamate
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aplastic anemia
severe hepatitis ionsomia, appetite suppression and weight loss |
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uses of felbamate
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refractory partial seizures
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levetiracetam
"vitamin K" mechanism pluses minuses |
mechanism: inhibition of Ca2+ currents?
Pluses: first dose is tx; no enzyme induciton minuses: IRRITABILITY |
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Topiramate
"dopamax" |
Mechanism: inhibition of Na+ channels; increase GABA opening; interfereance with flutmate binding
Adverse: memory and cognitive effects Uses: appetpite suppression, weight loss, migraine prophylaxis |
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Pregabalin
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mechanism:decreased release of neurotransmitters
adverse: makes you gobble (fat) |
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Vigabatrin
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visual field deficit
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p450 inducers
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phenobarbital
phenytoin carbamazepine ** requires enzyme synthesis--> takes time to take effect and wear off** |
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p450 inhibitors
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valproate
** no enzyme synthesis--> immediate inhibition** |
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AEDS and stevens johnson
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lamotrigine
watch for abdominal pain, vomiting, jaundice, fever |
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AEDs and hematologic damage
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Felbamate
watch for abnromal bleedig, acute fever, aemia symptoms |
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Long term effects of phenytoin
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- osteomalaxia
anemia teratogenesis facial carsening hirsuitism gingival hyperplasia neuropathy |
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2 drugs that exacerbate epileptic seizures
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Tramadol
Venflaxine |
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AEDs used for neuropathic pain
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Gabapeintin
Carbamazepine Pregabalin |
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AEDs used for bipolar disorder
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Lamotrogine
Valproate |
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AEDs used for migrain
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Valproate
Topiramate Zonisamide |
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First line for Idiopathic generalized epilepsy
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Valproic acid
Lamotrigine (pregnancy; risk of stevens johnson) Levetiracetam |
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Drug specific for childhood absence epilepsy and mechanism
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Ethosuximide
inhibition of T type calcium channels |
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Drugs with limited indications because of side effects
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Felbamate (aplastic anemia; hepatitis)
Vigabatrine Phenobarbitol |
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Drugs for focal epilepsy
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Carbamazepine
Valproic acid Lamotrigine Topiramate Levetericaetam Oxcarbazepine Gabapentin Phenytoin Phenobarbital |
