Flashcards in 9. Dementia Deck (14):
What is dementia?
- Progressive decline in higher cortical function...
- leading to a global impairment of MEMORY, INTELLECT and PERSONALITY...
- which affects the individual's ability to cope with activities of daily living.
How is dementia different from delirium?
Dementia = no impairment of consciousness
Delirium = impaired consciousness
Name the 4 main types of dementia and describe their typical onset/progression.
1. Alzheimer's disease (60%): gradual, progressive onset and decline
2. Vascular dementia (20%): abrupt or gradual onset, with step-wise decline (related to vascular episodes)
3. Lewy body dementia (4%): insidious onset with progressive but fluctuating decline (periods of remission)
4. Fronto-temporal dementia (2%): insidious onset, rapid progression
Describe the typical features of Alzheimer's disease.
1. memory loss, esp. names and recent events
2. language deficits
3. impaired visuospatial skills
4. later affective/behavioural symptoms, e.g. aggression
Describe the typical features of Lewy Body dementia.
1. fluctuant cognitive impairment
2. visual hallucinations
3. Parkinsonism: shuffling gait, increased tone, tremors, falls
Describe the typical features of frontotemporal dementia.
1. altered social behaviour and personality, e.g. depression, agitation
2. impaired judgement and insight, e.g. disinhibition
3. apathy, poor executive function
4. speech output falls eventually to state of mutism
Describe the typical features of vascular dementia.
Depends on area of brain affected by ischaemia and if acute/chronic ischaemia but can include:
- confusion and disorientation
- vision loss
Explain the pathophysiology of Alzheimer's.
Accelerated cortical neurone loss causing generalised cortical atrophy (narrowed gyri and wide sulci) due to formation of:
1. amyloid-beta plaques: incomplete breakdown of amyloid precursor protein... AB monomers aggregate to form extra-neuronal plaques... deposit at dendrites, affecting neuronal signalling and promoting inflammatory resp., and deposit in local blood vessels
2. neurofibrillary tangles: Tau protein (normally binds and stabilises microtubules) hyperphosphorylation... form intracellular twisted filaments
Describe the pathophysiology of vascular dementia
Neuronal ischaemia/damage due to:
1. arteriosclerosis of cerebral arteries
2. multiple small ischaemic/haemorrhagic strokes, inc. lacunar infarcts
3. cerebral small vessel disease, e.g. diabetes mellitus
Describe the pathophysiology of Lewy body dementia.
Intracellular accumulation of Lewy bodies (abnormal protein inclusions) throughout cortex and substantia nigra.
Describe the pathophysiology of frontotemporal dementia.
Diverse group of conditions with similar presentations but different pathologies:
1. frontotemporal lobar degeneration
2. Pick's disease (build-up of Tau proteins forming Pick bodies)
3. familial tauopathies
Name a rare cause of dementia.
Name 5 possible reversible causes of dementia.
3. vitamin deficiency (eg VitB12)
5. thyroid disorders