Dementia Flashcards
What is dementia?
acquired and persistant generalised disturbance of higher mental function in an otherwise fully alert person
What are the 4 primary types of dementia?
Alzhemiers - 60-75%
Lewy Body dementia - 10-15%
Fronto-temporal dementia - <2%
Huntingtons disease
What are secondary types of dementia?
multi infarct - vascular dementia - 20%
HIV, syphilis
trauma
metabolic - vit B1 deficiency, paraneoplastic syndromes
intracranial space - SOLs and hydrocephalus
drugs and toxins
What are the risk factors for Alzheimers disease?
females>males most common >85s if <65 = genetic related may be familial - amyloid precursor protein or presenillin 1 and 2 increased incidence in trisomy 21
What is the presentation of Alzheimers disease?
disorientation
memory loss
aphasia - can be naming, repeating or effortful
What is the pathology behind Alzheimers disease?
decreased size and weight of the brain - due to cortical atrophy
normally in frontal, temporal and parietal lobe and hippocampus
sulci widen and gyri narrow
hydrocephalus ex valco occurs - ventricle dilation
What can be seen microscopically in Alzheimers disease?
neurofibrillary tangles - often due to disregulated TAU protein
neuronal loss with astrocyte proliferation
Ab amyloid plaques - produced by cleavage of amyloid precursor proteins (APP)
Where are amyloid precursor proteins found (APP)?
on chromosone 21
meaning those with down syndrome have a double dose of it so have early onset Alzheimers
What do Ab oligomers promote?
mislocation of TAU which leads to Alzheimers
What is amyloid angiopathy?
extracellular eosinophillic accumulation
stains congo red
distrupts the BBB by local hypoxia causing excitotoxicity, oedem and serum leaking
What investigations are done for Alzheimers disease?
MRI - atrophy of the temporal/parietal lobes
SPECT - tempoparietal decreased metabolism
CSF - decreased amyloid: increased TAU ratio
What treatment is given for Alzheimers disease?
acetylcholine boosting treatment - cholinersterase inhibitors (Rivagistimine)
NMDA receptor blocker - mematine
What is the presentation of Lewy Body Dementia (LBD)?
frequent visual symptoms hallucinations memory affected later on fluctuates in severity from day to day extra pyradimal features of Parkinson's
What is the pathology of LBD?
degeneration of the substantia nigra
pallor in the substantia nigra where the preserved dopaminergic neurones run
What is seen microscopically in LBD?
loss of pigmented neurones
reactive gliosis
microglial accumulation
remaining neurones show Lewy bodies
What are lewy bodies?
aggregates of alpha synuclein and ubiquitin
What is the presentation of Huntingtons disease?
35-50yrs triad of emotional, cognitive and motor disturbances chorea myoclonus develop dementia later on in the disease
What are the investigations for LBD?
reduction of dopamine uptake on the DaT scan
What are the treatment options for LBD?
small dose levodopa
cholinesterase inhibitors
What are the genes behind Huntingtons disease?
autosomal dominant
huntingtin gene on chromosome 4p - mutant gene has additional CAG repeats
What are the investigations for Huntingtons disease?
MRI - loss of caudate heads
What is the treatment for Huntingtons disease?
mood stabilisers
What is the pathology of Huntingtons disease?
atrophy of basal ganglia esp caudate nucleus and putamen
cortical atrophy of frontal areas - later on
What is seen microscopically in Huntingtons disease?
neuronal atrophy of sriatal neurones in the basal ganglia
pronounced astrocytic gliosis
