Degenerative diseases - Alzheimer's, Dementia Flashcards
What is dementia?
A description of a set of symptoms which show an acquired decline in memory and other cognitive functions in an alert person sufficiently severe to cause functional impairment and present for more than 6 months
What are the major causes of dementia?
- Alzheimer’s disease
- Vacular dementia
- Dementia with lewy bodies
- Fronto-temporal dementia
- Parkinson’s disease + dementia
- Reversible dementias
What is Alzheimer’s disease?
A chronic neurodegenerative disease that usually starts slowly and worsens over time. It involes the build up of amyloid plaques and neurofibrillary tangles within brain tissue.
What is the pathogenesis of amyloid plaques in Alzheimer’s disease?
Abnormal breakdown of membrane Amyloid precursor proteins (involed in neuronal growth and repair), meaning that previously soluble breakdwon products are no longer soluble (Amyloid-beta). Clumps (plaques) of beta-amyloid form in between neurons, which disrupt conduction mechanisms. Plaques also illicit an inflammatory response, and cause amyloid angiopathy, which weakens vessel walls and increase risk of haemorrhage
What is the pathogenesis of neurofibullary tangles in Alzheimer’s disease?
The presence of amyloid plaques leads to the activation of kinase, which adds phophate groups to Tau proteins in the microtubules inside the neuronal cells. This causes a conformational change in Tau protein structure, which causes them to stop supporting microtubules, break away and form neurofibrillary tangles
What macroscopic changes occur due to neuronal cell death in alzheimer’s disease?
-
Atrophy
- Narrowing gyri
- Widening sulci
- Increased ventricular volume
What are the symptoms of alzheimer’s disease?
Progresses slowly over years
- Profound Loss of short term memory first
- Progresses to broad, often global cognitive dysfunction, behavioural change and functional impairment
- Disorientation
What is vascular dementia?
Dementia caused by problems in the supply of blood to the brain, typically a series of minor strokes, leading to worsening cognitive decline that occurs step by step
What are risk factors for vascular dementia?
- DM
- Hypertension
- Smoking
- Other vascular disease
How does vascular dementia present?
Problems occur in a stepwise fashion
- Frontal lobe, extrapyramidal, pseudobulber and emotional lability is common
- Urinary incontinence and falls without other explanation
- Executive dysfunction may predominate
- Gait abnormalities
What would you see in neuroimaging in someone with vascular dementia?
- Multiple large vessel infarcts
- White matter infarcts/periventricular white matter changes
What is dementia with lewy bodies?
A dementia syndrome that is characterized by the development of abnormal collections of (alpha-synuclein) protein within the cytoplasm of neurons (known as Lewy bodies)
How does dementia with lewy bodies present?
General
- Deficits of attention, frontal executive, visuospatial.
Of the following, Two = probable, One = possible:
- Fluctuations in cognitive function and alertness
- Prominent auditory and visual hallucinations - often with paranoia and delusions
- Parkinsonism
What drugs can worsen confusion in dementia with lewy bodies?
- Typical antipsychotics - haloperidol
- Levodopa
- Dopamine
How could you distinguish dementia with lewy bodies from delerium?
- Insidious onset
- No underlying illness found
- Complex hallucinations - not misrepresentation of stimuli
- Persistent delusions
- Antipsychotics worsen status
How would Parkinson’s disease with dementia present?
- Typical parkinsonian motor features
- Presentation variable - may resemble vascular, alzheimer’s or lewy body
- Often preceded by parkinson’s
What is frontotemporal dementia?
A group of disorders caused by progressive nerve cell loss in the brain’s frontal lobes or its temporal lobes. This invariably cause deterioration in behavior and personality, language disturbances, or alterations in muscle or motor functions.
What are the features of fronto-temporal dementia?
Early onset - insidious/slow
- Behavioural – personality change
- Speech disorder - altered output, stereotypy, echolalia, perseveration, mutism
- Neuropsychology - frontal dysexecutive syndrome. Memory, praxis and visuospatial function not severely impaired
- Lack of Insight - early on
What are the core features of dementia syndrome?
A - activities of daily living
B - Behavioural and Psychiatric Symptoms of dementia
C - cognitive impairment
D - Decline
What are the cognitive features of dementia?
Memory
-
Dysmnesia (memory impairment), plus one of the following:
- Dysphasia - expressive/receptive
- Dyspraxia - inability to carry out motor tasks
- Dysgnosia - difficulty recognising objects
- Dysexecutive function
Functional
- ADL’s
What are the behavioural and psychiatric symptoms of dementia?
- Psychosis
- Depression
- Altered circadian rhythms
- Agitation
- Anxiety
What physical signs can be seen in dementia?
- Signs of vascular disease
-
Signs of late dementia
- Primitive reflexes
- Global hyperreflexia