Dementia Flashcards
What is the histological changes in dementia
- brain atrophy particularly in the temporal lobe
- ventricles are larger
- sucli and gyre are lost
name the warning signs of dementia
- Memory loss
- Difficulty performing familiar tasks
- Problem with languages – might forget the name of a toothbrush
- Disorientation in time and place – forgotten at what time they have dinner or what time they do normal activities
- Poor or decreased judgement
- Problems keeping track of things
- Misplacing things such as keys
- Changes in mood and behaviour
- Trouble with images and spatial relationships
- Withdrawal from work or social activities
What is the definition of dementia
- Term used to describe a syndrome that is caused by a number of illnesses in which there is progressive decline in multiple areas of function
Which 3 things is there a decline of in dementia
- Decline in memory and recognition
- Decline in communication skills
- Inability to carry out daily activities
Name other behaviour and psychological symptoms of dementia
- agitation
- aggression
- wandering
- shouting
- repeated questioning
- sleep disturbance
- depression and psychosis.
name some types of dementia
- vascular dementia (17%)
- Alzheimer’s disease (62%)
- Parkinson’s disease (2%)
- frontal temporal (2%)
- dementia with lewy body (4%)
- mixed AD+ VaD (17%)
name some ways of reducing the risk of dementia
- look after your heart
- be physically active
- follow a healthy diet challenge your brain
- enjoy social activity
What are the risk factors for dementia (modifiable and non-modifiable)
Non-modifiable risk factors • Age (greatest risk factor) • Genetic predisposition • Family history • Downs syndrome
Modifiable risk factors
• Vascular Risk factors (high cholesterol, hypertension, diabetes)
• Cognitive inactivity (low education attainment)
• Environment (head injury)
• Depression
What are the two things that cause dementia pathophsilogically
- plaques and tangles
describe where plaques and tangles are
- Amyloid plaques – these are deposited outside of the neurones so they are extracellular
- Tangles – these are found inside the neurones so there intracellular
How do you get a definitive diagnosis of demintia/Alzehiemrs
- need to have plaques and tangles but you can only find this out in an autopsy post mortem
- therefore they can only be given a diagnosis post mortem
name the 3 hallmarks of dementia
- extracellular deposits of beta- amyloid peptide in senile plaques
- deposits of beta-amyloid peptide in cerebral vessels
- neurofibrillary tangles - the tau protein hyperphosphorylated and forms neurofibrillary tangles in cell bodes
What do plaques and tangles cause to happen
- neurotic dystrophy
- synaptic loss
- selective neuronal cell loss
how many neurones are lost before people have specific memory impairment
20-40% of cholinergic cells are lost
what 3 genes are associated with early onset alzhimeres disease
Amyloid precursor protein (APP) Chromosome = 21
Presenilin 1 (PSEN1) Chromosome= 14
Presenilin 2 (PSEN2) Chromosome= 1
describe the APP protein
- a single transmembrane polypeptide (110-140 kD)
- APP is abundantly expressed in neurones
- APP also expressed in glial cells and endothelial and smooth muscle cells
- helps neurone growth and repair
- over time APP is broken down and recycled
What do APP proteins produce
- Abeta peptide is a normal metabolic event
What happens when there is a mutation of APP
- they are associated with an increase in a beta production
what diseases are mutations in APP associated with
• Mutations in APP are associated with familial forms of early onset Alzheimer’s disease as well as with Cerebral amyloid angiopathy (CAA)
what mutation in APP is protective of Alzheimer’s disease
• One particular mutation A673T decreases Aβ production and is protective of AD
Describe the normal recycling pathway of APP
o Transmembrane protein is cleaved secretase enzymes (alpha, beta and gamma).
(!) The γ-secretase is made up of subunits. Of note are PSEN1 and PSEN2 because mutations in these can cause Alzheimer’s .
o In normal non-amyloidogenic pathway, alpha and gamma secretases do not form amyloid-beta peptides but cleave up the protein into soluble form which is recycled.
What is the most common mutation that causes alzherimers
PSEN1 being the most common
What does PSEN1 encode
- PSEN1 encodes presenilin-1
What are the Y secretease made up of
- it is made up of subunits
- PSEN1 and PSEN2 are impotent as mutations in these can cause AD