Epilepsy Flashcards
What is epilepsy?
A condition characterised by recurrent unprovoked seizures.
What is a seizure?
Neural correlate - abnormal and excessive excitation of a population of cortical neurons.
What is the prevalence of epilepsy?
0.4-1%
What is the aetiology of epilepsy?
Lots of causes, e.g: febrile seizures Birth trauma Intracranial infections Head injury Drugs and alcohol Cerebral tumours Genetic non-congenital epilepsies Cerebrovascular degenerations.
What is the pathophysiology of epilepsy?
Balance between excitation and inhibition shifted towards excitation, synchrony.
What do open Cl- channels lead to?
Hyperpolarisation
What are the features of juvenile myoclonic epilepsy?
Myoclonic jerks
Most common on waking
Onset early teens
Goes with fast (3.5-6Hz) spike and wave activity in EEG
How is epilepsy treated?
Anti-epilepsy drugs (AEDs)
E.g. carbamazepine, phenytoin, valproate, etc.
Around 70% of patients can expect to become seizure free with AED treatment
Drugs mainly target lots of ion channels
Surgery can be used when appropriate - e.g. to destroy tissue at seizure focus.
Surgery can make 90% of patients seizure free.
What is the mortality rate in epilepsy?
2 to 3 times higher than general population, even in well controlled patients.
Can be due to SUDEP (sudden death in epilepsy - can be during seizures or not during seizures)
Give an example of two genes associated with ADNFLE (autosomal dominant nocturnal frontal lobe epilepsy).
CHRNA4
CHRNB2
(Both nicotinic acetylcholine receptors)
Name some other familial epilepsy genes.
GEFS+
SMEI
BFNC
(multiple genes, multiple mutations)
How do we know the mutations identified are the causative mutations?
Convergence of evidence:
Same mutations present in different families, but not found in controls.
Different mutations found in different families, on the same gene or related genes.
Functional evidence:
Neurophysiology
- GABRA1 mutations lead to failure of receptors containing α1 subunit to form or reach plasma membrane.
