L8 - Dementia Flashcards
1
Q
What is dementia?
A
- Serious loss of cognitive ability in a previously unimpaired person, affecting behaviour, mood and personality
- Slow, progressive decline in range of cognitive and behavioural aspects
- Irreversible
- Symptoms vary depending on type of dementia
- May have prodromal states
- 50+ causes
2
Q
What are differential diagnosis?
A
- Vascular demential
- Lewy bodies
- Pick’s disease
- Huntingtons
- Alzheimers
- HIV/AIDS related
3
Q
What is vascular dementia?
A
Poor bloodflow within the brain e.g mini-strokes or mini-bleeds = part of brain does not function normally = diff symptom presentations
4
Q
What is Lewy body dementia?
A
- Deficits on tests of attention, executive function and visuospatial ability
- Closely related to parkinson’s
- Rare and underdiagnosed
- Improved methods of diagnosis
- Build up of a protein: alpha synuclein = causes neuronal loss = has a pattern of spread
- Rare family linkage, sporadic aetiology, APOE4 risk effect
5
Q
How has dementia changed in the DSM5?
A
- Mild neurocognitive disorder: cog deficits are present, but ability to be independent remains, less severe presentation, but can progress from mild to major = meant to allow for early detection
- Major neurocognitive disorder: Cog deficits present that interfere with independence
- Focus on memory impairment is reduced inc. decline with speech/language ability
6
Q
What is the clinical picture of alz?
A
- Progressive, unremitting, irreversible, major deficits in aspects of memory, attention, learning and behavioural control
- Basic sensory and motor function is relatively intact until end stages
- High co-morbidity of depression due to living alone, people trying to help them
- Can use MMSE as a questionnaire discussing time/place of test, repeating lists of words, arithmatic tests, basic motor skills
7
Q
What were the DSM criteria for Alz?
A
- Insideous onset and gradual decline of congitive function
- Presence of causal genetics based on family history
- OR decline in memory/learning and one other cog are, based on history of neuropsycholoigcal testing
- Steady cog decline without periods of stability
- No indicators of other psych, neurological or meducal problems responsible for the cog decline
8
Q
What are the 4 criteria of AD?
A
- Definite Alz: histopathological evidence
- Probable: clinical and neuropsychological examination shows dementia, cog impairments are progressive and in 2+ areas of cognition, onset between 40-90 yo
- Possible: dementia syndrome with atypical onset, presentation or progression is present without other known aetiology
- Unlikely: dementia syndrome with a sudden onset is present
9
Q
What is the pathology for Alz?
A
- Regional brain shrinkage
- Increased ventricular size
- Amyloid plagues
- Neurofibrillary tangles
10
Q
Why do some people get Alz?
A
- Genetics: deterministic genes and familial alz disease
- Sporadic: no known cause
- Genetics: risk factors
- Other risk factors: age, head injuries etc.
11
Q
What was the study of age?
A
- Major risk factor: every decade we increase, more have dementia and Alz
12
Q
What is the effect of genetics?
A
- Familial genes: APP, PSEN2, PSEN1 = causal genes, very rare
- APOE4: common genes low frequency but can cause
13
Q
What is the APOE gene?
A
- Chromosome 19: 3 different polymorphic alleles and 6 genotypes: e2, e3 and e4.
- E3 is very common and normal, e2 is rarest version, e4 is in the middle and relatively rare but overrepresented in Alz population, if both copies are e4 = increased risk and severity
- E2 is protective of alzheimers
- E4 = thinner cortex in brain
14
Q
What are deterministic genes?
A
APP mutation: presence of this = causes alzheimers
15
Q
How was the tau gene found?
A
- Family had a lot of strange patterns of behaviour e.g found stealing, tried to run child over, thought it was psychosis
- Then saw memory loss and confusion = saw dementia
15
Q
What are tangles?
A
- Tau gene - chromosome 17 - singular nucleotide change can cause various dementia
- For fronto-temporal dementia
- Microtubule associated protein tau: normal function of axonal structure = can become abnormal through hyperphosphorylation = tau binds to self = fibrils and these bind together = tangles
16
Q
Where does tau derive tangles in the brain?
A
- Frontal cortex
- Parietal cortex
- Temporal lobe
- Amygdala
17
Q
What are other risk factors?
A
- Head injuries
- Heart problems
- Stress
- Diet & cholesterol
- Gender
- Exercise
- Education level
- Environment
18
Q
What was a study on other causes?
A
- Closer someone lives to a busy road, higher risk of dementia = but how long is necessary e.g 5 years of living next to road or ?
- Poor env = higher risk
- Head injury = footballers have some form of neurocognitive disorder (older when football was heavier) = only 14
19
Q
What is Leqembi?
A
- Approved by FDA and NHS
- Stops plaque build-up in brain, should stop progression of Alz, mixed results = small effects
20
Q
Describe Acetylcholine:
A
- Not a general cholinergic lesion
- Striatal cholinergic neurones intact
- Only cortical neurones affected - temporal lobe most severely
- Arise from the nucleus basalis complex
- Part of limbic system
- Affects most probably late on in disorder
21
Q
What drugs have developed from acetylcholine?
A
- Many drugs from ach
- Helps behaviour and cog ability and maintain them
- Increase Ach in synapse and increase functioning
- Prevent degradation of ach in synapses
- Inhibits AchE which breaks down Ach
- Will not cure Alz
