Epilepsy Flashcards
What is Epilepsy?
A disease with recurring but irregular seizure activity.
> Causes epileptic seizures
> Two major classes:
—1. Generalized onset seizure
—2. Focal onset seizure
Epileptic Seizures
Episodes with extreme hyperpolarization of neurons, spreading over a large area.
> They are atypical and abnormal occurences
The two major classes of seizure are:
- Generalized Onset Seizure
- Focal Onset Seizure
Generalized Onset Seizure
Hyperpolarized activity spreads throughout various areas in the brain.
Focal Onset Seizure
Starts at a specific point in the brain, then spreads out.
Other Seizure Subtypes
Further categorization of generalized and focal onset seizures based on level of awareness and behaviour.
> Tonic-clonic seizures: convulsive behaviour
Absence seizures: “blacking out”
Other seizures: can involve changes in:
— Breathing, thinking, speech, emotions, sensations
Tonic-clonic Seizures
Convulsive behaviour
Caused by changes in muscle activity:
— stiffness (tonic) and jerkiness (tonic)
Also features aspects of absence seizures, such as “blacking out”.
Absence Seizures
Brief periods of altered awareness
> Or “blacking out”
No visible signs of seizure outside of seeming “zoned out”.
How are seizure types identified?
By characteristic EEG abnormalities.
— Different spikes correlate to types of seizure.
Symptomatic Seizures
> When the cause is known, the seizure is called symptomatic
> Typical causes:
—- Head Trauma
—- Metabolic disorders
—- Infection
—- Toxins
—- Tumours
Idiopathic Seizures
No known cause
> Seizure episodes can be triggered by a wide variety of stimuli, which vary between people.
Cognitive Symptoms of Epilepsy
> Impaired cognitive and psychosocial functioning
Disrupted sustained attention and executive function
Consciousness is disrupted during the seizure
Interictal (between seizure) consequences
Interictal Consequences of Seizure
> Connectivity between brain regions and networks is altered
> Cognitive disruption reflects dysfunction of the focal onset of seizures (in focal onset seizures)
Epilepsy Treatment Options
- Drug therapy: most common, basic treatment, used in most cases.
- Surgery: used for more difficult to treat epilepsy, or when there is no other option (such as when medication stops working)
Drug Therapy
Anticonvulsant medication, 3 major classes:
> Baribituates: mimic GABA
> Hydatoins: block sodium influx into the neuron
> recent drugs reduce the force of release of glutamate
Effective in 70-80% of patients, but patients can build a resistance to the drugs (or are simply already drug-resistant)
