Idiopathic Epilepsy Flashcards
what is a cluster seizure?
two or more seizures occurring within 24 hours
what is the prodromal phase?
altered behavior hours before seizure
what is a generalized seizure?
generalized neuronal hyper-excitability encompassing the entire cerebral cortex
both hemispheres
what is a focal seizure?
neurons of specific region of brain are involved in seizure focus
can affect any part of body, but head most often
what is the pathogenesis of seizures?
not completely understood
an imbalance in excitatory and inhibitory neurotransmission
what is the genetic mode of transmission of idiopathic epilepsy?
autosomal recessive
more than one gene involved
what is the age of onset of idiopathic epilepsy?
10 months- 5 years
for what ages should you do an MRI for onset of seizures?
less than a year
more that five years
what metabolic testing should you do for a dog with new onset of seizures?
CBS, chemistry profile, urinalysis
bile acid stimulation test
ammonia
what are some indications for starting an anticonvulsive medication?
status epilepticus
cluster seizures
intracranial lesion
increasing seizure activity with shortening interictal interval
what is the breakdown of categories of causes of status epilepticus?
40% idiopathic epilepsy
40% symptomatic (intracranial) epilepsy
20% reactive (extra-cranial) epilepsy
what are some at home options for cluster events?
rectal diazepam
intranasal diazepam
intranasal midazolam
rectal levetiracetum
pulse therapy levetiracetum
what is the mechanism of action of phenobarbital?
effects post synaptic barbituate receptor in presence of GABA
prolongs opening of chloride channels: hyperpolarization of cell membrane
what is the mechanism of action of bromide?
hyperpolarization of post-synaptic membrane via accumulation within cells
what is the mechanism of action of levetiracetam?
modulates release of neurtotransmitters via selective binding to the SVA2 protein
what is the mechanism of action of zonisamide?
blocks T-type calcium channels
inhibits voltage-gated sodium channels
enhances GABA release
inhibits glutamate release
what is the mechanism of action of pregabalin?
binds to CaVa2 unit of the calcium channel
reduced calcium influx diminishes excitatory neurotransmitter release
which medication has liver side effects as a concern?
phenobarbital
which medication should you not give to cats?
potassium bromide
what interactions do cannabinoids have?
inhibition of cytochrome P450 cytochrome oxidase
interference of diazepam derivatives and most likely also phenobarbital
what is the mechanism of action of ketogenic diets?
ketone bodies have anti-epileptic properties
fatty acids metabolized into ketone bodies when low amount of carbohydrates
dogs easily become ketotic
medium chain triglycerides more easily produce ketone bodies in dogs
what are the negative prognostic factors for seizure control?
presence of cluster seizures
age at presentation
duration of seizure disorder
what are the clinical manifestations of generalized seizures?
tonic-clonic
tonic
clonic
myoclonic
is glutamate excitatory or inhibitory?
excitatory
what channels does glutamate control?
sodium/calcium channels
which breeds are especially predisposed to seizures?
belgian shepherd
border terrier
finnish spitz
irish wolfhound
italian spinone
petite basset griffon de vendeen
labrador retriever
what are the potential causes of primary epilepsy?
idiopathic
hereditary
what is the half life of phenobarbital?
dog: 24-48 hours
cat: 34-43 hours
low protein diet decreases
how is bromide excreted?
renal
what are the side effects of levetiracetam?
rarely weakness
rarely sedation
very rarely excitement
how is levetiracetam metabolized?
minimal hepatic
renal excretion
how is zonisamide cleared?
hepatic- not P450
renal excretion
is zonisamide used for emergency therapy?
no- maintenance only
how is pregabalin cleared?
excreted unchanged through kidneys
how do ketogenic diets act to decrease seizures?
ketone bodies anti-epileptic
fatty acids and medium chain triglycerides produce ketone bodies
also decanoic acid
what is decanoic acid?
non-competitive AMPA receptor antagonist: inhibition of excitatory neurotransmission
are dogs that present at a very young age or old age less responsive to medications?
very young age
