Epilepsy and anticonvulsants Flashcards
What is epilepsy?
Occasional, sudden, excessive, rapid and local discharges of grey matter
High frequency
Epilepsy is a disorder of which part of the brain?
The cerebral cortex
Behavioural changes are related to what?
Site of discharge
Epilepsy affects what % of the population?
0.5-1%
What two methods can you use to record epilepsy?
EEG and MEG
What does an MEG record?
Magnetic activity of the brain
-Higher resolution than EEG (but more expensive!)
During an epileptic fit, brain activity is what?
Synchronised
What are the 3 main types of seizure
Grand mal (tonic clonic) Petit mal (absence) Partial seizure
What are the different stages of a grand mal seizure
Seizure onset
- seizure spreads from localised to entire cortex (almost instant)
Tonic phase
- v.high frequency across the whole cortex, rigid muscle activity
Clonic phase
- Synchronised activity at much lower frequency, more obvious muscle movement
Post ictal phase
- Synchronised activity still observed but no outward behavioral changes
Where do seizures arise?
Anywhere
Mostly cortical
How do seizures arise?
Cortical activity - dynamic balance between inhibition and excitation
Two levels (Intrinsic and Network)
Intrinsic - Ion channels
Network - Synaptic transmission
Destabilizing membrane ion channels have what sort of charge?
Positive
Stabilizing membrane ion channels have what sort of charge?
Negative
Which drugs block Na-channels
Phenytoin
Carbamazepine
Lomotrigine
Sodium valproate
Which drugs block Ca-channels
Gabapentin
Ethosuscimide
Pregabilin
