Wk 32 - Epilepsy 1 Flashcards
Define epilepsy
Neurological condition characterised by recurrent epileptic seizures unprovoked by any immediately identifiable cause
Define epileptic seizures
Clinical phenomenon resulting from occasional, sudden + excessive discharge of gray matter
Which type of people does epilepsy affect the most?
- Infants
- Elderly
- Less wealthy
What is epileptogenesis?
Process where normal brain tissue is functionally transformed into tissue capable of generating recurrent, spontaneous seizures
What are the 2 theories regarding the pathogenesis of epilepsy?
- Imbalance in inhibitory + excitatory NT - disruption of normal balance
- Abnormal neural connectivity - greater spread + abnormal neuronal recruitment by oscillatory networks
Outline the theory of pathogenesis of epilepsy regarding the disruption of normal balance between excitation + inhibition in the brain
Excitation:
- Ionic - inc inward Na+ + Ca++ currents
- NT - inc glutamate + aspartate
Inhibitory:
- Ionic - dec inward Cl- + outward K+
- NT - dec GABA
Outline the theory of pathogenesis of epilepsy regarding the abnormality in neural connectivity
Inc synchronization of neuronal firing due to:
- Enhanced excitatory transmission
- Failure of inhibitory mechanism
- Enhanced inter-neuronal connectivity
What are the 2 classifications of epilepsy?
- Clinical cases w/ no obvious identifiable cause (primary epilepsy, genetic predisposition)
- Clinical cases w/ obvious identifiable cause (symptomatic/secondary epilepsy)
What are the causes of obvious identifiable causes?
Presence of underlying neurological or neuropsychological abnormality due to brain injuries + CNS disease:
- Head injuries/birth traumas
- Congenital abnormalities
- Brain tumours
- Stroke
- Neurodegenerative diseases
- Meningitis, encephalitis
What are the 4 major phases of epileptic seizures?
- Pre-ictal or prodrome
- Ictal
- Post-ictal
- Inter-ictal
What is pre-ictal or prodrome?
- Period preceding seizure
- Lasts minutes to days
- Subject may act/feel different (ringing ears, deja vu, weird feeling in stomach)
What is ictal?
- Period of actual seizure
- Marked by typical physical, sensory + psychic changes
What is post-ictal?
- Period immediately following seizure
- Lasts minutes to hrs, depending on type, intensity + duration
- Associated w/ weakness, tiredness, somnolence, confusion
What is inter-ictal?
- Period btw seizures
- Marked by: emotional disturbance (fear, anxiety + apprehension)
What is the ILAE classification of epileptic seizures?
Based on onset location:
- Primary generalised: simultaneously in both cerebral hemisphere
- Partial/focal seizure: in localised focus in 1 hemisphere
- Secondarily generalised seizure: start as partial/focal then spread to include entire brain
