Epilepsy Flashcards
what is epilepsy
- neurological disorder/disease characterized by recurring epileptic seizures
- actually a collection of neurological disorders of varying etiologies
what are the Common diagnostic criteria of epilepsy
Any one of:
(1) At least two unprovoked seizures occurring more than 24 hrs apart
(2) One unprovoked seizure and a probability of further seizures similar to
the general recurrence risk (at least 60%) after two unprovoked
seizures, occurring over the next 10 years
(3) Diagnosis of an epilepsy syndrome
What are general etiologies?
- a brain injury or damage to the brain (physical, stroke, tumor)
- structural abnormalities that arise during brain development
- genetic factors (either inherited or random)
- a combination of two or more of the above
What is a Seizure?
- an electrical disturbance where neurons fire in a highly coordinated /
rhythmic manner
what is Focal / Partial Seizures
Focal seizure with retained awareness
- activity is localized to one area with a related effect (sensory, motor, etc.)
Focal seizure with a loss of awareness
- loss of consciousness and responsiveness; mobile or immobile
what is Generalized Seizures
Absence seizure
- brief loss of awareness; staring into space and subtle body movements
Tonic-clonic seizure
- abrupt loss of consciousness; loss of motor control including stiffening
and rhythmic contraction of muscles; loss of bodily function
- usually lasts less than two minutes and followed by confusion + lethargy
Status epilepticus
- a seizure that lasts more than five minutes
- can be life-threatenin
what are the Treatments
Pharmaceutical
- 50% success, 30% some improvement, 20% unresponsive
Surgery
- removal of the seizure focus
- corpus callosotomy (to prevent the generation of generalized seizures)
- hemispherectomy (totally malfunctioning hemisphere; rare)
Ketogenic diet
- high fat, sufficient protein, low carbohydrate
Deep brain stimulation
- permanent electrodes; pulses can prevent hypersynchronous activity
How does GABAergic control regulate excitatory neurotransmission to maintain normal brain electrophysiology?
GABAergic control of excitatory
neurotransmission is critical for
normal brain electrophysiology
what are Inhibition of Nav channels meds and how do they work
- most common class of anti-epileptic drugs
- inhibit Nav channels, which are critical for action potential generation
what are examples of the Nav channels meds
Phenytoin: tonic-clonic seizures
Carbamazepine: focal or tonic-clonic
seizures; NOT for absence seizures
Valproic Acid: for focal and generalized seizures
potential additional effect to increase GABA levels
Topiramate: for focal and generalized seizures
also inhibits glutamate receptors and augments GABAA receptors
what is the med for the Inhibition of T-type Ca 2+ channels
Ethosuximide
- indicated for absence seizures only
- inhibits low-voltage T-type Ca2+ channels, which regulate oscillations
what is the med for the Inhibition of L-type Ca 2+ channels
Gabapentin: capsules and tablets for focal and generalized seizures
what is the example for the nhibition of synaptic vesicle glycoprotein 2A (SV2A)
Levetiracetam: tablets for focal and generalized seizures
Brivaracetam: tablets, liquid, injection for focal (partial) seizures only
what is the med for the Inhibition of AMPA + kainate receptors
Perampanel: tablets for focal and generalized seizures
non-competitive antagonist at AMPA receptors
Topiramate: tablets and capsules for focal and generalized seizures
antagonist at both AMPA and kainate receptors
what are the Positive allosteric modulation of the GABA A receptor
- many anti-epileptic agents work in this manner
- bound drug increases the receptor ion channel open time and frequency
- as discussed previously, many agents have anxiolytic, sedative, hypnotic,
and anti-convulsive properties
what are the example of the Positive allosteric modulation of the GABA A receptor
Barbiturates: phenobarbital tablets / elixer for focal and generalized seizures
Benzodiazepines: diazepam and lorazepam tablets for focal and
generalized seizures
Topiramate: tablets and capsules for focal and generalized seizures
give an example for the Inhibition of GABA transaminase (GABA-T)
Vigabatrin: tablets for focal and generalized seizures
NOT a first-line therapy due to vision loss in at least 1/3 patients
