Seizure Disorders Flashcards
(149 cards)
Epilepsy usually defined as having ?
two unprovoked seizures at least 24 hours apart
Process by which the brain becomes prone to having repeated seizures (epilepsy) ?
Epileptogenesis
Pathophysiology ?
Abnormal electrical activity discharge; single abnormal neuron is insufficient to cause a clinical seizure
In order for seizure to occur, recruitment of excitatory neurons with inhibition of inhibitory neurons seizure propagation
- *single neuron mis firing is not enough to cause it seizure they need to recruit more or propagate the abnormally firing neurons to cause a seizure
- *
Old theory of why seizures occurred ?
loss of inhibitory neurons (GABA)
New theories of why seizures occur ?
loss of excitatory neurons (that stimulate the inhibitory neurons)
Injury leads to axonal “sprouting” to other excitatory neurons
Basis for neuronal excitation is the ?/
action potential
Voltage gated channels
- excitatory ?
Sodium and calcium (hypopolarize)
Voltage gated channels
- inhibitory ?
Potassium (hyperpolarize)
Ligand-gated receptors
- excitatory ?
Glutamate – NMDA Ca++ influx
Ligand-gated receptors
- inhibitory ?
Gamma-aminobutyric acid (GABA) – Cl- influx
Genetic alterations in Na channels are linked to ?
epilepsy and febrile seizures
Genetic alterations in Na channels are linked to what drugs ?
phenytoin (Dilantin) - target Na channels
carbamazepine (Tegretol),
Lacosamide
Genetic alterations in Ca channels are linked to ?
childhood absence epilepsy
Drugs that affect Ca channels ?
ethosuximide ( remember this)
Genetic mutations in K+ channels are linked to what drugs ?
Topiramate (Topamax)
Levetiracetam (Keppra)
Retigabine
Role of glial cells????
“Supportive cells”
Removal excess glutamate from the extracellular space
Manage extracellular potassium and calcium
play a role in the likely hood these people have seizures
If activity remains localized , what type of seizure is it ?
partial seizure
If bilateral, generalized activity , what you of seizure ?
generalized
Most common type in adults (approx. 60%) ?
partial seizure
- *Can be further categorized
- *
Usually arise in the temporal lobe (temporal lobe epilepsy) ?
partial seizure
Hippocampal sclerosis aka?
“Ammon’s horn sclerosis”
Hippocampal sclerosis patho ?
Loss of neurons in the hippocampus from sclerosis
Hippocampal sclerosis is a common feature of what ?
temporal lobe epilepsy
Hippocampal sclerosis is also seen in ________ and other types of dementia.
Alzheimers
** Good prognostic factor for response to surgery - remove the poriuton of the brain - resolves sxs. **