brain disease 2 Flashcards
epilepsy means
‘to seize’ having repeated seizures
seizure
abnormal, transient highly synchronous brain activity
types
partial/focal (simple and complex)
generalised
incidence
prevalence of active epilepsy about 0.5-1%
5% will expereince a non febrile seizure
childhood absence epilepsy
4-12 years
absence of seizures/ petit mal (10-30 sec episodes of unresponsivity sometimes eye rolling, lip smacking, hand shaking, several hundred per day)
characteristics 3 Hz spike-wave discharge
mutations in low threshold voltage-dependent Ca channels
resolves with pathology during puberty
temporal lobe epilepsy
late childhood and adolescence
most common epilepsy of adults
epileptogenic focus in hippocampus and or amygdala and or parahippocampal gyrus (recurrent excitatory circuits)
complex partial seizures often preceded by aura
may develop into secondary generalised tonic-clonic /grand mal seizure
causes of epilepsy
- over 2/3 idiopathic in nature
- reflex seizures, precipitated by a trigger e.g. flashing light…
- genetic - mutations in Na channels
- cerebrovascular disease
- tumours
- alcohol/drugs
- trauma/hypoxia
- infection
- metabolic disorder
- developmental disorders
- degenerative disorder
- pathological synaptic plasticity (kindling)
PRODUCING AN IMBALANCE IN EXCITATION AND INHIBITION IN THE NERVOUS SYSTEM
treatments acute
- generalised or complex partial - recovery position
- simple partial- reassurance, maintain safe environment
- benzodizepenes
treatment for chronic
- pharmacological e.g. ethosuximide (blocks/modulate Ca and Na channels) and carbamazepine (modulates Na channels potentiates GABA receptors)
- surgical e.g. remove tumour, arteriovenous malformation or epileptogenic tissue (temporal lobe, hippocampus)
- electrical e.g. vagal, depp brain stimulation
- avoidance of seizure triggers
Sz incidnence
about 0.6% population worldwide
peak onset early 20s
Sz pathology
increased levels of dopamine in the mesolimbic pathway
negative symptoms of Sz
flat affect, alogia, anhedonia, asociality, avolition
causes of Sz
genetics: 50% concordence in mono zy twins - DISC-1
env: 50% in mono az twins
developmental: infection in utero, poor diet, asphyxia
social facotrs: env, stressful relationship
drug abuse: cannabis/cocaine cause or effecT?
dopamine hypothesis excessive D2R stimulation
redcued NMDAR function
mice with reduced expression of NMDARs exhibit
excessive motor activity
stereotypy
deficits in social and sexual interactions
symptoms that are ameliorated by typical and atypical antipsychotics
pathology depression
reduced hippocampal volume
vascular lesions
reduced BDNF