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?
- 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
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?
- 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?
- 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
What drugs can worsen confusion in dementia with lewy bodies?
- Typical antipsychotics - haloperidol
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?
Dysmnesia (memory impairment), plus one of the following:
- Dysphasia - expressive/receptive
- Dyspraxia - inability to carry out motor tasks
- Dysgnosia - difficulty recognising objects
- Dysexecutive function
What are the behavioural and psychiatric symptoms of dementia?
- Altered circadian rhythms
What physical signs can be seen in dementia?
- Signs of vascular disease
Signs of late dementia
- Primitive reflexes
- Global hyperreflexia
When performing a mental state exam for someone with suspected dementia, what would you want to exclude as differential diagnoses?
- Delerium - Agitation, restlessness, poor attention, fluctuating consicousness
- Depression - low affect, poor motivation
What investigations would you do in someone with dementia to look for potetnially reversible causes?
- Bloods - FBC, U+E's, B12, Folate, ESR, Calcium, LFT's, TSH, CRP
- Consider EEG, Neuroimaging or LP
When is neuroimaging indicated in the context of a presentation of dementia?
- Age < 60
- Sudden onset/brisk decline
- High risk of structural pathology
- Focal CNS signs
How does delerium differ from dementia in terms of mode of onset?
Delerium is acute
How does delerium differ from dementia in terms of fluctuation?
Diurnal/hourly fluctuation common in delerium
Can have deterioration in dementia in the evening
How does delerium differ from dementia in terms of hallucinations?
Common in delerium, whereas late sign in dementia (except lewy body dementia)
How does delerium differ from dementia in terms of fear, agitation and aggression?
This is common in delerium, and is uncommon in the early stages of dementia
How does delerium differ from dementia in terms of motor signs?
Tremor, myoclonus and asterixis common in delerium
Motor signs late in delerium
How does delerium affect speech?
- Dysarthric - slurred or slow speech that can be difficult to understand
- Dynomic - fluent type of aphasia where an individual has word retrieval failures and cannot express the words they want to say
How does delerium differ from dementia in terms of memory?
Short and long term affected in delerium, whereas long term memory is often spared until later on in dementia
How would you manage someone with dementia?
Modify reversible factors
- Cholinesterase inhibitors - mild to moderate
- Memantine - moderate to severe
Adequate care at home
- Support caregivers
- Provide extra care for ADLs
- Carer education
What is important to remember when managing someone with dementia?
Notify DVLA at diagnosis
If early dementia license may be yearly
“those with poor short term memory, disorientation or lack of insight should almost certainly not drive”
What are risks associated with dementia?
- Aggression towards carers/family
- Self neglect
- Abuse towards patient
- Financial abuse
Name some of the acetylcholinesterase inhibitors used in dementia?
What sort of drug is Memantine?
NMDA receptor blocker - reduces cholinergic neuron destruction
How would you manage agitation/aggression in a demented patient?
Non medical interventions
- Familiar environemtn
- Avoid precipitants
- SSRI's - if depression prominent
How would you assess dementia severity?
- Montreal Cognitive assessment
What are classed as reversible causes of dementia?
- B12 deficiency
- Intracerebral bleeds/tumours
- Normal pressure hydrocephalus
Where are changes in alzheimer's disease normally found in the brain?
Neocortex and hippocampus
What cholinesterase inhibitor is used to treat dementia with lewy bodies?
What cholinesterase inhibitor can be used to treat alzheimer's disease?
What can galantamine be used for?
What is the triad of symptoms commonly seen in normal pressure hydrocephalus?
- Gait disturbance
What is always important to remember to screen for when assessing someone with suspected dementia?
What is the defintion of capacity?
Ability to understand information relevant to a decision or action and to appreciate the reasonably forseeable consequences of taking or not taking that action or decison
What are the steps to assesing capacity?
- Presume capacity - always assume unless there is evidence to the contrary
- Maximise capacity - if lacking capcaity
- Bad decisions not necessarily incapable
- Mental disorder or severe communication disorder
What classes of mental disorders can lack capacity?
- Sensory impairment
What are the 5 aspects of decision making that need to be present in order for someone to be deemed to have capacity?
- Making decision
- Understanding decisions
- Communicating decisions
- Retaining memory of decisions
What is power of attorney?
Power granted by person (when they have the capacity to do so) to make sure that their future decisions are safeguarded, even when they lode the ability to make these decisions themselves
What are the different types of power of attorney?
- Continuing - financial only
- Welfare - decisions about health and wellbeing
- Combined - both financial and decisions
What is guardianship?
Legal authority for someone to make decisions and act on behalf of a person who has lost capacity to make certain decisions.
May cover money, property, welfare and health
What are the 4 main areas of cognition tested in the MMSE?
- Memory/Registration and Recall
- Attention and calculation
What are disadvantages to using the MMSE?
- Biased against people with poor education due to elements of language and mathematical testing
- Bias against visually impaired
- Limited examination of visuospatial cognitive ability
- Poor sensitivity at detected mild/early dementia