epilepsy 1 Flashcards
What is epilepsy?
chronic neurological condition affecting the brain
characterised by a tendency to have recurrent, unprovoked epileptic seizures
unprovoked by any immediately identifiable cause
What happens during a seizure?
sudden surge of electrical activity in the brain caused by excessive discharge of neurons in gray matter and involuntary change in behaviour/how a person feels for short period of time
spontaneous and unprovoked
another name for a seizure
ictus
people with higher rates of epilepsy
infants
elderly
less wealthy
co-morbidities
depression anxiety suicidal ideation cognitive dysfunction migraine trauma
social and econimic limitationf of epilepsy
stigma - social exclusion and discrimination
driving restrictions
employment restrictions
mortality from epilepsy
x2-3 premature death
increased incidence of suicide
SUDEP most common form of death
SUDEP
sudden unexpected death in epilepsy
What happens during a seizure?
abnormal hyper-synchronous electrical activity of neuronal networks
too many brain cells becoms excited at same time
generates ‘electrival storm’ in brian
What is epileptogenesis?
process where normal brain tissue is functionally transformed into tissue capable of generating recurrent, spontaneous seizures
theories of epilepsy
- imbalance in inhibitory/excitatory neurotramsmission
2. abnormality of neural connectivity
Theory 1: disruption of normal balance between excitation and inhibition in the brain
too much excitation in epilepsy
- inc inward Na and Ca currents
- inc glutamate and aspartate NTs
to little inhibition
- dec inward Cl and outward K
- dec GABA NT
Theory 2: abnormality in neural connectivity
greater spread and abnormal neuronal recruitment by oscillatory networks
due to
- enhances excitatory transmission
- failure of inhibitory mechanisms
- enhanced inter-neuronal connectivity
- changes in intrinsic neuronal properties
2 classes of epilepsy
- no obvious identifiable cause - idiopathic/primary epilepsy, genetic origin
- obvious identifiable cause - symptomatic/secondary epilepsy
causes of symptomatic epilepsy
brain injuries/CNS diseases:
- head injuries/birth traumas
- congenital abnormalities
- brain tumours
- stroke
- neurodegenerative diseases
- infections -> meningitis, encephalitis
4 phases of an epileptic seizure
- pre-ictal/prodrome
- ictal
- post-ictal
- inter-ictal
pre-ictal phase of seizure
before the seizure
mins-days
feel/act differently - aura
-> see/smell/hear/taste something for no reason, stomach, ringing in ears
ictal phase of a seizure
period of the seizure
physical, sensory, psychic changes
post-ictal phase of a seizure
immediately after seizure
mins-hrs
weakness, tiredness, confudion, Todd’s paralysis, somnolence
inter-ictal phase of a seizure
period between seizures
may get emotional disturbances - fear, anxiety, apprehension
classification of seizures ILAE 1981
BASED ON ONSET LOCATION
primary generalised seizures
- begin in both cerebral hemispheres
partial/focal seizures (simple/complex)
- begin in lodcalised area in 1 hemisphere
secondarily generalised seizures
- start off as partial/focal seizure (aura)
- spread to entire brain
6 types of generalised seizures
absence (petit mal)
tonic-clonic (grand mal)
myoclonic
clonic
tonic
atonic
