Alzheimer's 1 (PB) Flashcards
What is dementia?
progressive cliical syndrome of deteriorating mental function significant enough to interfere with activities of daily living
What does dementia afffect?
cognitive domains - memory, thinking, language, orientation, judgement
social behaviour - emotional control and motivation
How is a diagnosis of dementia made?
impairment in at least 2 cognitive domains* that lead to a significant functional decline* that cannot be exaplained by another disorder/adverse effect of medication
- memory, language, behaviour, visuospatial function
- *enough to affect activities of daily living
erly onset/young onset dementia
dementia that develops before the ge of 65yrs
What is mild cognitive impairment?
cognitive impairment that does not fulfil the criteria for dementia
- only 1 cognitive domain is affected, deficits don’t significantly affect ADLs
ADL
activities of daily living
causes of dementia
- Alzheimer’s disease
- vascular dementia
- dementia with Lwey bodies (DLB)
- frontotemporal dementia (FTD)
pathological features of Alzheimer’s disease
atrophy of the cerebral cortex
formation of amyloid plaques and neurofibrillary tangles
acetylcholine production in affected neurons is reduced
What causes vascular dementia?
reduced blood supply to the brain
caused by cerebrovascular disorders - small infarcts (stroke), cerrbralamyloid angiopathy, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)
features of dementiawith Lewy bodies (DLB)
cortical and subcortical Lewy bodies
What are Lewy bodies?
abnormal deposits of protein inside nerve cells
DLB and PD dementia classifications
- cognitive symptoms and motor features of PD within 1yr classed as having dementia with Lewy bodies
- PD who develop dementia >1yr classed as having PD demenita
What is frontotemporal dementia (FTD) characterised by?`
progressive degeneration of the frontal and/or temporal lobes
gradual progression
usually presents in middle age
can present in 30s or 90s
rarer causes of dementia
- PD dementia
- progressive supranuclear palsy
- Huntington’s disease
- prion disease
- normal pressure hydrocephalus
- benign tumours
- chronic subdural haematoma
- metabolic/endocrine disorders (chronic hypocalcaemia, recurrent hypoglycaemia)
- vitamin deficiencies (B12, thiamine)
- infections (HIV, syphilis)
What is Alzheimer’s disease?
irreversible progressive brain disease that slowly destroys memory and thinking skills
AD and neurons
AD disrupts
- communication between neurons
- metabolism of neurons
- repair of neurons
genes involved in AD
APP - amyloid precursor protein
PSEN-1 - presenilin gene)
PSEN-2
APOE2, 3, 4
3 genes that influence AD in younger people
APP
PSEN-1
PSEN-2
Gene defects and PSEN1 and 2
2 presenilin genes can be affected: PSEN-1 and PSEN-2
PSEN-1 is a fault on chromosone 14
PSEN-2 is a fault on chromosome 1
What chromosome is affected in APP (amyloid precursor protein) gene defect of AD?
fault on chromosome 21
gene defects that affects older people (>65yrs)
apolipoprotein E (APOE)
3 forms: APOE2, APOE3, APOE4
APP and AD pathogenesis
APP (amyloid precursor protein) is broken down
- first by alpha and betw secretase
- then by gama secretase
forms differnent substitutents such as A beta 42, A beta 40 and P3
Abeta42 is toxic
it aggregates and forms amyloid plaques which lead to neuronal death
Tau protein and AD pathogenesis
Tau forms insoluble filaments that accumulates as neurofibrillary tangles
features of Alzheimer’s disease
- memory loss
- decline in language
- apraxia (can’t preform movements on comand)
- agnosia (can’t ID objects, people)
- progressive loss of function
- behavioural changes (agitation, aggression, wandering, delusions)
- loss of sight
- depression
