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
incidence of depression
3% japan
18% USA
average 10%
women 2x men
stroke definition
neurological deficit of cerebrovascular cause that persists
beyond 24 hours or is interrupted by death within 24 hours”
difference between stroke and transient ischameic attach
the latter is a syndrome with of stroke like symptoms that resolve within 24 hours
crucial points- brain function ceases…
brain function ceases 60-90 seconds of an ischaemic event
irreversible brain damage if ischaemic event > 3 hours duration
2 types of stroke
ischaemic
haemorrhagic
ischaemic strokes
embolus (wandering clot)
thrombus (locally-formed clot)
systemic hypoperfusion e.g. heart attack
haemorrhagic strokes
entry of blood into CNS via rupture of a blood vessel/sinus or an aneurysm
types of haematomas in the brain
epidural
subdural
subarachoid
intracerebral
epidural haematoma
traumatic damage to the meningeal artery or dural venous sinus (e.g. blow to the head)
subdural haematoma
caused by rapid movement of head causing tearing of the cerebral being as it enters a dural venous sinus
subarachnoid haemotoma
caused by damage (e.g. aneurysm) to a cerebral artery or vein subsequent bleeding into the subarachnoid space
intracerebral haemotomas
cause by damage of a blood vessel within the brain
incidence of stroke
10% deaths worldwide
2nd leading cause of death
95% occur>45 years
risk factors for stroke
- high blood pressure (?)
- high cholesterol
- diet
- physical inactivity
- drugs of abuse (alcohol, cigarettes, cocaine, amphetamine)
treatment for stroke preventative
anticoagulaants ; carotid angioplasty/endarterectomy; diet/lifestyle
treatment for acute ischamic stroke
thromoblysis- tissue plasminogen activators (within 3 hours); thromobectomy; angioplasty; stenting
treatment for acute hemorrhagic stroke
surgery
treatment for chronic post stroke
control of hypertensions; aspirin; physical and occupational therapy
alzheimer’s disease 1907 alois alzheimer pathology
profound loss of neurones
plaques (amyloid)
neurofibrillary tangles (hyperphosphorlyated tau)
incidince of alzheimers
1.5%-2% worldwide
causes of alzheimers
• age, 10% over 65, 50% >85
•genetics but predominantly for early onset e.g. ApoE4 gene
variant
•trauma
• high blood pressure/hypercholesteremia (but statins
ineffective),
•environmental factors?
Alzhiemrs treatmetn
• symptoms - acetyl cholinesterase inhibitors, NMDA
receptor antagonists e.g. memantine
• risk - NSAIDs and caffeine, intellectual stimulation, diet and
exercise
