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
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2
Q

What are differential diagnosis?

A
  • Vascular demential
  • Lewy bodies
  • Pick’s disease
  • Huntingtons
  • Alzheimers
  • HIV/AIDS related
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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

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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
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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
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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
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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
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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
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9
Q

What is the pathology for Alz?

A
  • Regional brain shrinkage
  • Increased ventricular size
  • Amyloid plagues
  • Neurofibrillary tangles
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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.
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11
Q

What was the study of age?

A
  • Major risk factor: every decade we increase, more have dementia and Alz
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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
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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
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14
Q

What are deterministic genes?

A

APP mutation: presence of this = causes alzheimers

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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
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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