learning pack 5 Flashcards
What is dementia?
- A set of symptoms that include loss of memory, mood changes, and problems with communication and reasoning
- Progressive –> symptoms will gradually get worse
Origins of dementia: Degenerative
- Alzheimer type dementia
- Lewy body dementia
- Parkinson’s disease
- Motor neurone disease
- Frontotemporal dementia
- Huntington’s disease
- Multiple sclerosis
Origins of dementia: Vascular
- Multi-infarct dementia
- Lacunar state
- Binswanger’s disease
- Cerebral amyloid angiopathy
Origins of dementia: Infective
- Aids-dementia complex
- BSE/new variant creutzfeldt-jakob disease (CJD)
- Herpes simplex encephalitis
Origins of dementia: Post-neurological insult
- Open or closed head injury
- Carbon monoxide poisoning
Origins of dementia: Space occupying lesion
- Chronic subdural haematoma
- Primary or metastatic intracranial tumour
Origins of dementia: Toxic
- Alcohol related dementia
- Heavy metal poisoning (e.g. lead, mercury)
Origins of dementia: Metabolic/endocrine
- Hypothyroidism
- Vitamin B12 deficiency.
Origins of dementia: Other causes
- Epilepsy
- Beheet’s syndrome
What is Alzheimer’s disease
- Physical disease named after the doctor who first described it (Alois Alzheimer)
- During the course of the disease, proteins build up in the brain to form structures called ‘plaques’ and ‘tangles’
- This leads to nerve cell death and loss of brain tissue
- People with Alzheimer’s also have a shortage of certain chemicals in their brain, so signals are not transmitted as effectively
- Alzheimer’s is a progressive disease
Symptoms of Alzheimer’s: Early/Mild
- Lapses of memory, confusion
- Problems with finding the right words, repetition
- Slower at grasping new ideas
- Finding it harder to make decisions
- Loss of interest in other people or activities
- Blame others for taking mislaid items
- Unwilling to try new things/adapt to change
Symptoms of Alzheimer’s: Middle/Moderate
- Frequently confused/disoriented in time and space/ forget names of people, places, appointments and recent events
- Experience mood swings, scared and frustrated by their increasing memory loss
- Become more withdrawn due to loss of confidence or to communication problems
- Difficulty carrying out everyday activities
- Need help with managing their daily care
Symptoms of Alzheimer’s: Late/Severe
- Require a great deal of help, become totally dependent upon others for care
- Very pronounced loss of memory
- Can’t remember close family members
- Increasingly frail/shuffling, falls, unsteady walking, confined to bed/wheelchair
- Difficulty in eating and swallowing
- Weight loss or over-eating
- Incontinence
- Loss of speech
- Restlessness
- Distressed/aggressive…may not understand what is happening to them
How do we establish the onset of Alzheimer’s
Main early clinical manifestation is short-term memory loss
A neuropsychological element consisting of amnesia and one or more of the following:
- Aphasia - problems understanding language
- Apraxia - inability to carry out tasks
- Agnosia - inability to recognise things
This can be evidenced by:
- Repeating of questions
- Forgetting birthdays/anniversaries, appointments to meet with friends or family
- Needing to be reminded of the day/date
However, long term memory can be preserved for some time
How do we establish the onset of Alzheimer’s
A neuropsychiatric component with symptoms such as psychiatric disturbances and behavioural disorders:
- Depressioin (approx. 66%)
- Paranoia (30%)
- Hallucinations (most commonly auditory, 15%)
- Aggression (20%)
Deficits in activities of daily living (more pronounced over time):
- Wandering/loss of intent -> forgetting what to do
- failure to wash or dress to a usual standard
- Self neglect of diet can lead to weight loss
- Neglect of household tasks lead to comments about cleanliness of the house
How do we diagnose Alzheimer’s
- History
- Perspectives on impairment from the patient, close friend or a relative is recounted to the GP to corroborate symptoms and impact on daily functioning - Cognitive tests
- Assessing mental processes
- Referral of patient to memory clinic - Physical examination
- Blood tests include kidney and liver function, thyroid gland activity, vitamin levels - Brain scan
- MRI examination
What are the causes of Alzheimer’s
- No single factor has been identified
- It is likely that a combination of factors are responsible, including: age, genetic inheritance, environmental factors, lifestyle, general health
- Progressive neurodegenerative changes due to an abundance of plaques (made of an abundance amyloid) and tangles (made an abundance of tau)
- Reduction of neurotransmitters contribute to the profile of symptoms (acetylcholine, glutamate, GABA)
What is the amyloid cascade hypothesis?
Hardy and Higgins (1992)
- There are two hallmark pathologies identified in. Alzheimer’s
1. Beta amyloid peptide (ABeta)
2. Neurofibrillary tangles (NFT) of the binding protein tau - An excess of ABeta triggers the disease which leads to the formation of NFTs, neuronal cell death and dementia
What is the cholinergic hypothesis
Bowen et al (1976)
- Acetylcholine is used in arousal, memory and attention
- Projections from the basal forebrain influence activity in the rest of the brain (including hippocampus)
- Amyloid deposits prevent effective neurotransmission and receptor binding which produces deficits in plasticity
- Alzheimer’s treatment options target nicotinic acetylcholine receptors e.g. Aricept, Exelon and Reminyl
Risk factors for dementia: Age
- Greatest risk factor for dementia
- Increased risk may. be due to factors associated with ageing:
- Higher blood pressure in mid-life
- Increased incidence of heart disease and stroke
- Changes to nerve cells, DNA, cell structure
- Weakening of the body’s natural repair systems
- Changes in the immune system
- Myelin model of neurodegeneration
- Age-related breakdown in the protective membrane of axons from mid-life can increase the likelihood of developing AD (Bartzokis, 2004)
Risk factors for dementia: Genetics
- Apolipoprotein E (APOE)
- The influence of inherited genes for late-onset AD is small: most people do not have a genetic predisposition for/against AD development (as opposed to early-onset AD)
- APOE e2 –> rare (present in 7% of people)
- -> Appears to be neuroprotective
- -> If AD occurs, it usually develops much later in life - APOE e3 –> most common allele (79%)
- -> neither decreases nor increases risk - APOE e4 –> increases risk for AD, earlier onset (14%)
- -> Cumulative risk (e4/e4) - far more likely to develop AD
Risk factors for dementia: Environment
- Recent speculation on pollution levels ‘causing’ 11% of dementia cases (Chen et al, 2017)
- Likely to be other factors at play, and the precise contributory factors to such results are largely to be determines
Risk factors for dementia: Activity levels (Health/Medical history)
- High blood pressure, cholesterol levels, diabetes, miid-life obesity, and stroke put individuals at increased risk
- Medical status and cognitive decline appear related (Leoutsakos et al, 2012)
- Physical exercise as protective (Lindsay et al, 2002)
Risk factors for dementia: Activity levels (Social activity)
- People who are more socially active have a slightly reduced risk of developing dementia
- Interaction with others boosts hippocampal neurogenesis and reverses memory. decline in mice (Hsiao et al, 2014)
Risk factors for dementia: Activity levels (Mental activity)
- People who take part in mental activities, reading, learning, doing puzzles are less likely to develop dementia compared with those who do not engage in these activities (Baumgart et al, 2015).
What is mild cognitive impairment?
- The presence of acquired cognitive abnormality greater than expected in relation to age and education
- But it has to be in the absence of dementia and detrimental effects upon daily living