Flashcards in Epilepsy and its treatment Deck (37)
a disease characterized by a tendency to recurrent unprovoked seizures
abnormal, excessive synchronized discharge of cerebral neurons
NB: epileptic seizures are a clinical manifestation of epilepsy
Comment on the age of incidence of epilepsy
Huge variety in age of incidence of epilepsy
- childhood adolescence (20 ish)]- genetic predesposition?
- later in life (75)]- secondary to brain injury e.g. Alzheimer's, stroke etc
What is SUDEP?
Sudden Unexpected Death in Epilepsy (SUDEP)
It is a primary brain disorder (“short circuited” brain that fails to reboot)
Best way to prevent SUDEP?
Control the seizures
How to categorise the causes of epilepsy?
- Idiopathic (70%) i.e. genetic: mendelian-2% risk or non-mendelian-47% risk ("complex")
- Symptomatic (30%) i.e. secondary to brain injury: acquired or inherited
Mechanism of innate immunity in environmentally-acquired epilepsy
HMGB1 is released in chronic epilepsy -> binds to Toll-like receptors -> inflammatory cascade (cytokine release) -> cytokines interact w/ NMDA receptors -> hyperexcitability -> chronic seizures -> more HMGB1 released
Mechanism of adaptive immunity in environmentally-acquired epilepsy?
Autoantibodies against VGKC, NMDA, AMPA, GABA-a, GAD etc
Mechanism of inherited brain injury causing epilepsy?
Malformation of Cortical Development (MCD)
How do we classify epilepsy?
According to anatomical location of seizure onset
Loci identified by GWAS
- SCN1a (VGSC)
How does a seizure in the latero-temporal cortex manifest?
How does a seizure in the medial temporal lobe manifest?
How does a seizure in the occipital lobe manifest?
How does a seizure in the occipital pole manifest?
Standardise Recording convention on EEG for epilepsy?
Distance between electrodes within 10-20% of AP and lateral dimensions of skukk
Describe why a deflection appears on an EEG
Synchronised discharge from a set of neurons -> Na+ influx -> sudden depletion of Na+ ions -> EEG -ve deflection
What appearance does epilepsy have on EEG?
Spike and slow wave
Limitations of using EEG for epilepsy?
- many layers of scalp diminish signal
- Bell’s reflex (blinking causes artefact)
- scalp muscles give artefact
How to categorise seizures?
- absence, tonic, tonic-clonic, myoclonic, atonic
simple partial, complex partial, secondary generalised
Main causes of death from epilepsy in the UK?
- status epilepticus -> can't breathe -> hypoxia
- LOC -> drowning
What is generalised epilepsy?
- `Extensive, synchronised discharge in both cerebral hemispheres + LOC
- Global ictal discharge
What is focal (partial) epilepsy?
Localised, synchronised discharge in one part of the brain
Describe tonic seizure
Describe tonic-clonic seizure
Tense, jerk, repeat
Describe myoclonic seizure
Describe atonic seizure
No muscle tone
Describe absence seizure
Describe simple-partial seizure