Week 5 Flashcards
define dementia
Dementia is a syndrome, usually of chronic or progressive nature, which involves impairment of multiple higher cortical functions, such as memory, thinking, orientation, comprehension and language.
what is the incidence and prevalence of dementia?
- incidence 200 per 100,000
- prevalence 1500 per 100,000
what proportion of people over 80 have dementia?
1/6
what are late onset (65+ y/o) causes of dementia?
- Alzheimer’s disease (55%)
- Vascular dementia (20%)
- Lewy body (20%)
- Others (5%)
what are causes of early onset (<65 y/o) dementia?
- Alzheimer’s disease (33%)
- vascular dementia (15%)
- frontotemporal dementia (15%)
- other (33%): toxic (alcohol), genetic (Huntington’s), infection (HIV, CJD), inflammatory (MS)
what investigations are performed when for suspected dementia?
- routine: bloods, CT/MRI
- cognitive assessments
- others: CSF, EEG, functional imaging, genetics
what is the speed of dementia progression in Creutzfeldt-Jakob disease (CJD)?
rapid progression
what is the speed of dementia progression in vascular dementia?
stepwise progression
what is the most common neurodegenerative condition?
Alzheimer’s disease
what is the mean age of onset of AD?
70 years old (25% < 65y/o)
what is the pathophysiology
of AD?
Hallmarks:
- beta-amyloid plaque accumulation.
- Tau tangles: abnormal tau protein accumulation formes neurofibrillary tangles.
risk factors Alzheimer’s disease
- advanced age
- genetic predisposition (APOE, trisomy 21, APP, PSEN1, PSEN2)
- family history
- CV risk factors: hypertension, diabetes, obesity, hypercholesterolemia
- lifestyle factors: physical inactivity, smoking, diet high in saturated fats
- traumatic brain injury
what are clinical features of temporo-parietal dementia?
- early memory disturbance
- language and visuospatial problems
- personality preserved until later
what are clinical features of frontotemporal dementia?
- early change in personality/behaviour
- often change in eating habits
- early dysphasia
- memory/visuospatial relatively preserved
what is the pathology of dementia with Lewy bodies?
abnormal accumulation of alpha-synuclein protein > Lewy bodies
what are clinical features of dementia with Lewy bodies?
- early visuospatial and executive dysfunction
- prominent fluctuation
- Parkinsonism and visual hallucinations common
what is the medical treatment for Alzheimer’s (+/- Lewy body dementia)?
cholinesterase inhibitors (treat cholinergic deficit):
- donepezil, rivastigmine, galantamine
NMDA antagonist (memantine)
what is Parkinsonism?
A clinical syndrome with 2 or more of:
- bradykinesia (slowness of movement)
- rigidity (stiffness)
- tremor (shakiness)
- postural instability (unsteadiness/falls)
what are causes of Parkinsonism?
- idioptathic Parkinson’s disease > dementia with lewy bodies.
- drug-induced (e.g. dopamine antagonists).
- vascular parkinsonism (lower-half)
- multiple system atrophy (MSA)
- cortico-basal degeneration
- progressive supranuclear palsu (PSP)
risk factors of PD
- genetic (LRRK2, Parkin, GBA)
- environmental (pesticides, smoking, caffeine)
clinical diagnosis of PD
- bradykinesia + 1 or more of: tremor, rigidity, postural instability
- no other cause/atypical features
- slowly progressive (>5-10 years)
- good response to dopamine replacement treatment
what are the cardinal signs of parkinsonism?
- tremor: unilateral and at rest.
- bradykinesia > progressive
- postural instability
what are some non-motor signs of PD?
- olfactory loss (anosmia)
- autonomic dysfunction (constipation, urinary and bowel dysfunction, erectile dysfunction)
- REM sleep behaviour disorder
- psychiatric features: depression, anxiety, hallucinations
what functional imaging can be used to grade PD?
dopamine transporter SPECT
what is the early medical treatment of PD?
- L-dopa
- dopamine agonists: ropinirole, rotigotine, apomorphine, pramipexole
- MAO-B inhibitors: selegiline, rasagiline, safinamide
- COMT inhibitors: entacapone, tolcapone, opicapone
what are drug-induced complications in PD?
- motor fluctuations - levodopa wears off
- dyskinesias (involuntary movements)
- psychiatric - hallucinations, lack of impulse control
what are complications of PD?
- balance/falls/fractures
- dementia (50% after 10 years)
- speech, swallow
- gait freezing
what is the late treament for PD?
Drugs:
- prolong levodopa half life: MAO-B inhibitors, COMT inhibitor, slow release levodopa.
- add oral dopamine agonist.
- continous infusion (apomorphine, duodopa)
- Functional neurosurgery (deep brain stimulation)
- allied health professional +/- care package
WHO definition of stroke
- focal neurological deficit (loss of function affecting a specific region of the CNS) due to disruption of blood supply.
In practise, what are the three main causes of localised interrupted blood supply?
- atheroma + thrombosis of artery causing ischaemia (e.g. internal carotid artery thrombosis).
- thromboembolism (for example , from left atrium) causing ischaemia.
- ruptured aneurysm of a cerebral vessel causing haemorrhage (=/- dostal ischaemia due to spasm of artery).
what is a localised area of brain death called?
regional cerebral infarct
what are 2 common sites of ruptured vessels causing haemorrhagic stroke?
- basal ganglia - microaneurysms form in hypertensive patients.
- Circle of Willis - Berry anaeurysm forms in hypertensive patients.