What is the definition of epilepsy?
a chronic neurological disorder characterized by recurrent and unpredictable seizures
How are epilepsies characterized?
type of seizure and EEG
What are always common presentations diagnostically for epileptic seizures
excessive EEG discharges with SYNCHRONIZED activity of a group of neurons
What is primary epilepsy? How are they treated
no specific anatomic cause (70% of seizures arize from this type) treated with chronic antiepileptic drugs
What is secondary epilepsy?
epilepsy caused by some definable source such as brain tumors, stroke, infection, or injury
How is secondary epilepsy treated?
drugs are given until the primary cause of the seizures is corrected
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)
How are antiepileptic drugs selected?
they are selected based on seizure type
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
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
What are the signs and symptoms of complex partial epilepsy?
IMPAIRED CONSCIOUSNESS, dreamy states with or without automatisms, may spread
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
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
What are absence seizures?
brief loss of consciousness, happens in kids mostly associated with rapid eye blinking for several secs
What are myoclonic seizures?
occurs at any age, short epidsodes of muscle contractions
What are febrile seizures?
associated with young kids and fevers generalized tonic clonic with short duration do not ususally cause damage
What is status epilepticus?
Repeated seizures without recovery between them. Last around 30 min can lead to cardio collapse and brain damage. MED EMERGNECY
What does an EEG of generalized seizures look like?
Highly synchronized involves pretty much all of the lines
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
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
Which drugs inhibit NA channels?
carbameazepine phenytoin lamotrigine and valproic acid
Which drugs inhibit voltage gated Ca channels?
ehtosuxumide and valproic acid
Which drugs enhance inhibitory GABA transmission?
barbiturates, benzodiazepines, valproic acid and gababpentin
What dare some nonpharmacological means of treating epilepsy?
lobotomy and vagal nerve stimulation through implanted pulse generators
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
What is cabamazepine used for?
- partial simple and complex and tonic clonic
- NA blockade, suppresses firing and propagation of abnormal APs
- Orally absorbed
- - induces hepatic enzymes to metabolize it therefore need to increase dose over time
What does Valproic acid do?
- -choice of drug for myoclonic seizures
- -very hepatotoxic
- -reduces propagation of abnormal brain discharge (Na, Ca, and GABA)
What are the pharmacokinetics of Valproic acid
- -orally effective rapidly absorbed
- -high protein binding
- -metabolized by liver
What is divalproex?
- valproic acid+Na valproate
- - improves GI tolerance
What is Ethosuximide? What is its mechanism of action
- drug of choice for absence seizures
- - blocks T-type Ca channels supressing rhythmic activity
- - NOT Bound to proteins
- hepatic metabolism
What do the barbiturates (phenobarbital and primidone) treat and how do they work?
- treat simple partial, tonic clonic, and febrile
- -faciliate activation of GABA
Pharmokinetics of barbiturates
- hepatic metabolism
- freely penetrates brain
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
What is Lamotrigine
- inhibits release of glutamate blocks NA channels
- -metabolized by the liver
- use for simple and complex partial and tonic clonic
What is Gabapentin?
- enhances GABA transmission
- - not metabolized by liver-
- not bound
- - elimination through kidneys
- -tx of simple or complex partial and tonic clonic
What is pregabalin
- blocks ca and release of glutamate
- used for simple and complex partial seizures
What is topiramate?
- blocks na and increase activity of GABA receptors POST SYNPATICALLY
- - simple and complex partial and tonic clonic
What is zonisamide?
- blocks na and t-type Ca
- -used for treating simple and complex partial and tonic clonic
What are some common side effects of anti-epileptic drugs?
- drowsiness and seation
- - atatxia
- - nausea
- -skin rash
- -weight gain and loss
What causes gingival hyperplasia?
What causes heptotoxicity
valproic acid and carbamazepine
What are the preferred drugs to treat simple partial seizures, complex, and tonic clonic seizures?
What are the preferred drugs to treat absence seizures?
What are the preferred drugs to treat myoclonic seizures?
Clonazepam and Valproic acid
What drug is used to treat febrile seizures?
What drugs are used to treat status epilepticus?
Diazepam and phenytoin