Dementia Flashcards
Describe the epidemiology of dementia.
Affects approx 5-10% of population over the age of 65.
Approx 20% of those over 80 yrs
What are the three most common causes of dementia?
Alzheimer’s disease
Vascular dementia
Dementia with Lewy bodies.
Define Alzheimers disease.
Primary chronic progressive neurodegenerative dementia characterized by
extracellular deposition of b-amyloid protein and intracellular neurofibrillary tangles.
Define mild cognitive impairment
Impairment in some cognitive domains but insufficient to qualify
for diagnosis of dementia or to affect quality of life.
Describe the pathophysiology of alzheimer’s disease.
Characterised by extracellular deposition of amyloid plaques containing b-42 peptides and intracellular accumulation of neurofibrillary tangles containing hyperphosphorylated tau protein (microtubule protein).
It remains unclear which is the
causative pathology.
Neurone count is reduced particularly in hippocampus, mesial temporal and precuneate cortex.
What would a patient with Alzheimer’s disease complain of in their history?
Reliable history is best obtained from relative.
Gradual deterioration of cognitive functions:
- Initially, anterograde amnesia, change of personality, apathy, loss of concentration and
disorientation. May be accompanied with psychiatric manifestations (hallucinations and
delusions) . - Language is typically spared until late.
- Dysphasia, apraxia (difficulty using tools) and visuospatial difficulties often develop.
- In late stages, cognitive impairment in all cognitive domains (memory, language, visuospatial), myoclonus, seizures, behavioural disturbances, incontinence and loss of independence.
What would be found on examination of a patient with Alzheimer’s disease?
Mini-Mental State Exam is a useful screening tool (
What is Vascular dementia?
May occur in isolation or coexist with Alzheimer’s disease (mixed dementia).
Typically occurs in individuals with significant vascular risk factors.
Usually characterised by stepwise deterioration in cognitive function.
What would examination and assessment reveal in a patient with vascular dementia?
Neuropsychological assessment reveals patchy cognitive impairment.
May be evidence of previous strokes on history, physical examination and/or cerebral imaging.
Describe how Dementia with Lewy bodies is characterised pathologically.
Characterised by Lewy Bodies (aggregates of protein within nerve cells) in cerebral cortex.
Overlap with idiopathic Parkinson’s disease. Many patients exhibit similar parkinsonian motor features.
What are the clinical features of dementia with Lewy bodies?
Main feature is fluctuating cognitive impairment with visual hallucinations.
- Often clearly formed and stereotyped in nature
- May mimic delirium dye to fluctuating nature.
Give examples of “other” causes of dementia?
Not alzheimers, vascular or Lewy body related
Creutzfeldt- Jacob disease:
Rapidly progressive of dementia caused by accumulation of an abnormal, transmissible prion protein isoform).
Frontotemporal dementia:
Presents with marked personality change or dysphasia.
Relatively preserved memory.
What degenerative neurological disorders can dementia be a feature of?
Huntington’s disease
Wilson’s disease
Corticobasal degeneration
Progressive supranuclear palsy
Present in about a third of indiv with Parkinson’s disease.
What investigations would you perform for a patient with suspected dementia?
Diagnosis is largely clinical, examinations are performed to rule out any treatable causes.
In some patients with an atypical presentation/that are young more extensive investigations are performed that could include:
Vit B12, syphilis, thyroid function, calcium, glucose.
Cerebral imaging (CT or MRI) to exclude space-occupying lesion or hydrocephalus. -usually displays cerebral atrophy in dementia but may provide additional diagnostic info.
Neuropsychology assessment to document pattern of cognitive impairment.
Electroencephalography may show diagnostic periodic complexes in CJD
Lumbar puncture may provide evidence of raised intracranial pressure in inflammation, infection or CJD.
How would you manage a patient with dementia?
Management is largely supportive. Cholinesterase inhibitors (eg Rivastigmine and galantamine) modestly reduce cognitive impairment in alzheimers.
Treatment of vascular risk factors is important in vascular dementia..
May reduce rate of progression.
In most indie long-term care is eventually required.
