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What is the definition of epilepsy?
a chronic neurological disorder characterized by recurrent and unpredictable seizures
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How are epilepsies characterized?
type of seizure and EEG
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What are always common presentations diagnostically for epileptic seizures
excessive EEG discharges with SYNCHRONIZED activity of a group of neurons
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What is primary epilepsy? How are they treated
no specific anatomic cause (70% of seizures arize from this type) treated with chronic antiepileptic drugs
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What is secondary epilepsy?
epilepsy caused by some definable source such as brain tumors, stroke, infection, or injury
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How is secondary epilepsy treated?
drugs are given until the primary cause of the seizures is corrected
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What is the goal of antiepileptic drug therapy?
use the simplest drug regimen (usually only monotherapies are used sometimes two drugs but usually no more than this)
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How are antiepileptic drugs selected?
they are selected based on seizure type
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What is partial epilepsy and what are its subtypes?
- - Originated from a small group of neorons that constitute the seizure focus, may become generalized
- - Simple and Complex
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What are the signs and symptoms associated with Simple partial epilepsy?
focal motor, sensory, autoniomic or psychic disturbances, does not spread, no impairment of consciousness
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What are the signs and symptoms of complex partial epilepsy?
IMPAIRED CONSCIOUSNESS, dreamy states with or without automatisms, may spread
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What are the subtypes of generalized seizures? what are the general symptoms for generalized seizures?
tonic clonic, absence, myoclonic, febrile, status epilepticus
symptoms: immediate loss of consciousness, convulsive or non-convulsive, both hemispheres involved
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What are tonic clonic seizures?
most common and dramatic form. tonic phase(<1min) sudden loss of consciousness and rigidity loss of respiration. Clonic(2-3 min) rhythmic contractions. followed by confusion and exhaustion
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What are absence seizures?
brief loss of consciousness, happens in kids mostly associated with rapid eye blinking for several secs
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What are myoclonic seizures?
occurs at any age, short epidsodes of muscle contractions
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What are febrile seizures?
associated with young kids and fevers generalized tonic clonic with short duration do not ususally cause damage
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What is status epilepticus?
Repeated seizures without recovery between them. Last around 30 min can lead to cardio collapse and brain damage. MED EMERGNECY
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What does an EEG of generalized seizures look like?
Highly synchronized involves pretty much all of the lines
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What do antiepileptic drugs do?
- -block the origin of the seizure inducing activity
- - block the spread of the seizure inducing activity
- - reduce of slow the synchronization of neuronal activity
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How do antiepileptic drugs work?
- alter ion conductances:
- - inhibit voltage activated NA ion changels thus reducing firing and increasing refractory period
- - inhibit voltage CA channels and decrease rhythmic activity
- enhance inhibitory GABAergic neurotransmission
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Which drugs inhibit NA channels?
carbameazepine phenytoin lamotrigine and valproic acid
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Which drugs inhibit voltage gated Ca channels?
ehtosuxumide and valproic acid
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Which drugs enhance inhibitory GABA transmission?
barbiturates, benzodiazepines, valproic acid and gababpentin
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What dare some nonpharmacological means of treating epilepsy?
lobotomy and vagal nerve stimulation through implanted pulse generators
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What does phenytoin do?
- Oral administrtaion for chronic tx IV for emergencies
- - plasma bound
- enhances metabolism of other drugs.
- metabolism enhanced by CARBAMEZEPINE
- metabolism inhibited by Chloramphenicol and sulfonamide
- -Fosphenytoin is prodrug used IV and IM
- blocks NA and Ca channels
- used for partial simple and complex and tonic clonic also IV for status epilepticus
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What is cabamazepine used for?
- partial simple and complex and tonic clonic
- NA blockade, suppresses firing and propagation of abnormal APs
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Carbamazepine pharmacokinetics
- Orally absorbed
- - induces hepatic enzymes to metabolize it therefore need to increase dose over time
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What does Valproic acid do?
- -choice of drug for myoclonic seizures
- -very hepatotoxic
- -reduces propagation of abnormal brain discharge (Na, Ca, and GABA)
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What are the pharmacokinetics of Valproic acid
- -orally effective rapidly absorbed
- -high protein binding
- -metabolized by liver
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What is divalproex?
- valproic acid+Na valproate
- - improves GI tolerance
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What is Ethosuximide? What is its mechanism of action
- drug of choice for absence seizures
- - blocks T-type Ca channels supressing rhythmic activity
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Ethosuximide pharmokinetics?
- Oral
- - NOT Bound to proteins
- hepatic metabolism
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What do the barbiturates (phenobarbital and primidone) treat and how do they work?
- treat simple partial, tonic clonic, and febrile
- -faciliate activation of GABA
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Pharmokinetics of barbiturates
- oral
- hepatic metabolism
- freely penetrates brain
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What benzodiazepines used for and how do they work?
- used to tx acute status epilepticus IV
- -and myoclonic and absence seizures: clonazepam
- potentiate GABA actions
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What is Lamotrigine
- inhibits release of glutamate blocks NA channels
- -metabolized by the liver
- use for simple and complex partial and tonic clonic
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What is Gabapentin?
- enhances GABA transmission
- - not metabolized by liver-
- not bound
- - elimination through kidneys
- -tx of simple or complex partial and tonic clonic
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What is pregabalin
- blocks ca and release of glutamate
- used for simple and complex partial seizures
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What is topiramate?
- blocks na and increase activity of GABA receptors POST SYNPATICALLY
- - simple and complex partial and tonic clonic
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What is zonisamide?
- blocks na and t-type Ca
- -used for treating simple and complex partial and tonic clonic
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What are some common side effects of anti-epileptic drugs?
- drowsiness and seation
- - atatxia
- - nausea
- -skin rash
- -weight gain and loss
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What causes gingival hyperplasia?
phenytoin
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What causes heptotoxicity
valproic acid and carbamazepine
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What are the preferred drugs to treat simple partial seizures, complex, and tonic clonic seizures?
- phenytoin
- -carbamazepine
- -loratigine
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What are the preferred drugs to treat absence seizures?
ethosuximide
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What are the preferred drugs to treat myoclonic seizures?
Clonazepam and Valproic acid
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What drug is used to treat febrile seizures?
phenobarbital
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What drugs are used to treat status epilepticus?
Diazepam and phenytoin
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