Alzheimers Flashcards
Onset
- 40-90
- most often after the age of 65
Risk
- 1% at the age of 60
- 5% at the age of 65
- doubles every 5 years
- 40% at 85
More common with increasing age
-among those older than 75 the risk is 6x greater than the risk for vascular dementia
AD is more common than vascular
- AD is 50-70%
- VD is 15-20%
Risks for Downs
- Age, Downs, Apolipoprotein e4 allele
- female sex, head injury, postmenopausal oestrogen decline
- possible risk factors: family history of Downs, PD and vascular factors
Protective factors
- apolipoprotein E2 allee
- smoking, NSAIDS, oestrogen, premorbid intelligence and education
Presenelin 2 gene
- on chromosome 1
- linked to early onset
Presenelin 1 gene
- chromosome 14
- early onset
Beta amyloid precursor protein gene
- chromosome 21
- APP coding area is on the long arm of ch21 and is impllicated in early onset dementia (Downs have 3x copies)
- mutation on codon717 on APP genecan cause excessive deposition of beta amyloid protein
Apolipoprotein E4
- chromosome 19
- increases risk of late onset dementia of Alzheimers type
- if you have one copy you have 3x incidence of AD than no E4 gene, multiple copies increase the risk
Diagnosis
- clinical examination
- MMSE
- Blessed dementia scale
- neuropsychological tests
- need deficits in 2 or more areas of cognition
- progressive worsening of memory and other cogniive functions
- no disturbance of consciousness
- absence of other diseases that could account for cognitive deficits
Diagnostic procedures in AD
- CT excludes other causes
- MRI shows reduced grey matter, hippocampus, amygdala and temporal lobe volumes
- SPECY- reduced blood flow to temporal and parietal regions
- PET- reduced blood flow and metabolism in temporal and parietal regions
- MRS- abnormal synthesis of membrane phospholipids early in the disease
- amyloid PET imaging- shows deposition of beta amyloid even in preclinical stages of dementia
Psychiatric symptoms in AD
- delusions in 15%
- auditory and visual hallucinations 10-15%
- depression requiring treatment in 20% of patients
Behavioural symptoms in AD
- BPSD
- apathy in 59.6%
- depression in 58.5%
- irritability in 44.6%
- anxiety in 44%
- agitation in 41.5%
Average survival rate in AD
-8 years
Progression of AD
- increased agitation
- frequent emotional outbursts
- poor sleep
- wandering
- terminal phase: v. disorientated, amnestic and incontinent
AMTS
- cut off is 7 or 8/`0
- looks at memory and orientation only
MMSE
- cut off 24/30
- takes 5-10 minutes to complete
- tests orientation, memory , concentration, language, praxis and gnosis
CAPE
- comprehensive Clifton assessment for the elderly
- intended to assess level of disability and estimate need for care
DRS
- clinical dementia rating scale
- used to measure severity and stage of clinical illness
- ranges from 0-0.5, through to mild and moderate to severe dementia
- 6 domains
ACE
Addenbrooke Cognitive Examination
-100 point scale
NPI
Neuropsychiatric inventory
- rates frequence and severity of a range of neuropsychiatric symptoms
- 12 behavioural areas
CAMCOG
- comprehensive cognitive test
- takes 40 mins
- score out of 104
- tests orientation, comprehension, perception, memory and abstract thinking
Clock drawing test
-reveals test of praxis and offers qualitative and quantitative information
Cholinesterase inhibitorys
- Donepezil (aricept), rivastigmine (exelon) and galantamine (reminyl)
- used in mild to moderate cognitive impairment
- potentiate the cholinergic neurotransmitter to improve memory and goal directed thought
Donepezil
- well tolerated
- widely used
- long plasma half life of 70 hours
- permits once daily dosing
- total plasma protein binding
- highly selective reversible inhibition of ACh
- side effects: GI, headache, dizzinesss, muscle cramps
- 5mg OD-10mg OD
Rivastigmine
- more likely to cause GI S/Es than donepezil
- may be better in PDD
- affects acetylcholinesterase and butylrylcholinesterase
- can be given as a patch
- 1.5mg BD to 6mg BD
Galantamine
- more likely to cause GI S/Es
- direct nicotinic stimulatory action
- 4mg BD-12mg BD
Memantine
- non-competitive
- PCP site, NMDA antagonist
- protects neurons from glutamate
- better tolerated than AChE Inhibitors
- used in treatment of moderate to severe AD or those who do not tolerate ACHEIs
- 5mg-10mg OD
Olanzapine and risperidone
-increase stroke risk x2 and are not used in dementia
Poor prognositc factors in AD
- male
- onset before 65
- prominent behavioural problems
- parietal lobe damage
- observed depression
- severe cognitive deficits such as apraxia
- absence of misidentification syndrome
Psychosis in AD
- 30-50%
- delusions more common than hallucinations
- Capgras
- the phantom boarder (someone living in their house)
- mirror sign
- TV sign
- magazine sign
