Epilepsy Flashcards
What is the definition of a seizure
Clinical manifestation of a disordered and hyper synchronised discharge in a network of cerebral neurons
What are the THREE types of generalised seizures
briefly describe the characteristics of each
1) Absence
childhood, sudden loss and return of consciousness
No aura and no post-ictal state
2) Myoclonus
Sudden, brief, shock-like. arm jerks. sleep deprivation and alcohol.
3) Tonic- Clonic
gasp, fall, tongue bitten and incontinence, noisy breathing
What are the Focal (partial) seizures
Often an aura, spreads. Loss of awareness and automatisms
What are auras
epigastric rising sensation.
olfactory and gustatory
What is ictogenesis
Inter-ictal spike: short burst of epileptiform lasting 200ms
micro domains: possible basis of focal seizures
high frequency oscillations (ripples)
How does neuronal activity differ?
Burst firing behaviour of neurons
Hyper-synchronised firing of networks
What are absences
Connections between thalamus contain loops, membrane and synaptic properties cause oscillations. Disturbances may cause spike and wave firing
BURSTS OF ABNORMAL ACTIVITY FROM CORTEX TO THALAMUS
How does vigabitrin work
How does Tiagabine
GABAG transaminase inhibitor (high GABA levels prevent fading of inhibition)
GABA reuptake inhibitor
Lamotrigine
- when is it used?
1st line - focal and generalised seizures
myoclonus and absences
Carbamazepine
- how does it work?
Acts on sodium channels, suppresses burst activity and spread of seizures. Partial and generalised seizures
Valproate
-what is the mechanism of action?
Uncertain mode of action, GABA, inhibits excitatory transmission. 1st line for partial and generalised
SIDE EFFECTS IN WOMEN
Phenytoin
- what is the mechanism of action
- when is it used?
Acts on sodium channels, suppresses burst activity and spread of seizures. useful in emergencies
Levetiracetam
- what is it?
- how does it work?
Broad spectrum agent, synaptic vesicle protein 2a
well tolerated/no side effects
How do you deal with ‘status epileptics’
BE PREPARED
IV benzodiazepine + phenytoin
IV levetiracetam or valproate or lacosamide
SUMMARY OF DRUG USE
1) Absence - VELB
2) Myoclonus - VBL
3) GTC - CLVPT
4) Focal - CLTL
1) Valproate, ethosuximide, lamotrigine, BDZ
2) Valproate, BDZ, levetiracetam
3) CBZ, LTG, Valproate, phenytoin, toparimate
4) Carbamazepine, lamotrigine, topiramate, levetiracetam
