Dementia Flashcards
What is dementia?
a progressive irreversible decline in cognitive function over several months
Types of dementia
- Alzheimer disease
- Vascular dementia
- Lewy body dementia
- Frontotemproal
- Parkinson’s disease with dementia
- Aids related
Cognitive symptoms of dementia
What lobe is involved?
- impaired memory - temporal
- impaired orientation - temporal
- impaired learning capacity - temporal
- impaired judgement - frontal
Non cognitive symptoms of dementia
- behavioural symptoms - agitation, aggression, sexual disinhibition
- depression + anxiety
- insomnia
- daytime drowsiness
- visual + auditory hallucinations
- persecutor delusions
How is dementia diagnosed?
By exclusion:
- exclude delirium
- exclude organic causes of cognitive decline:
- hypothyroidism
- hypercalcaemia
- B12 deficiency
.
Look for features of progressive cognitive decline, impairment of daily living in patients with a normal conscious level
What must be excluded when making a diagnosis of dementia?
- exclude delirium
- exclude organic causes of cognitive decline:
- hypothyroidism
- hypercalcaemia
- B12 deficiency
Diagnosis of Alzheimer’s dementia
Clinically but hippocampal atrophy on imaging is supportive
Macroscopic pathological features of Alzheimer disease
- hippocampal atrophy
- Global cortical atrophy
- Sulcal widening
- Gyri narrowing
- Enlarged ventricles (primarily lateral + 3rd)
Microscopic pathological features of Alzheimer disease
Plaques
Tangles
What are Alzheimer plaques composed of?
Amyloid beta
What is amyloid precursor protein?
How is it normally broken down?
What pathology can occur?
- A protein involved in repairing neurones after damage
- Normally it is replaced + chopped up into soluble parts by a + gamma secretases
- In Alzheimer disease, B secretase causes insoluble breakdown > formation of B amyloid plaques
How are plaques formed in Alzheimer disease?
Amyloid precursor protein is broken down by B secretase into insoluble parts > forming B amyloid plaques
Outline Alzheimer disease in relation to Tau tangle formation
- B amyloid plaque induce pathological response in neuron > hyperphosphrylation of Tau proteins
- change in shape of Tau proteins
- reduced support of cytoskeleton
- neuron death
- aggregate into tangles
Function ofTau proteins
Play a role in stabilising microtubules within neuronal cytoskeleton
Types of Alzheimer disease
Sporadic (most common)
Familial
Outline sporadic Alzheimer disease
- 90-95%
- causes are poorly understood
- increasing prevalence with age
Outline familial Alzheimer disease
- 5-10%
- early onset dementia
- PSEN1/2 genes implicated > mutation of gamma secretase
Relationship between Down syndrome and Alzheimer disease
Disease can present as early as 40 years old
Symptoms of Alzheimer disease
- initially symptoms hard to detect
- short term memory loss initially
- motor and language skills affected
- long term memory loss
- disorientation
What is used to assess severity of dementia?
Mental state examination
Treatment of Alzheimer disease
- Acetyl cholinesterase inhibitors pyridostigmine
- Memantine (glutamate receptor antagonist) for advanced cases
Early symptoms of Lewy body dementia
Cognitive symptoms:
- distressing hallucination
- depression
- REM sleep disorders - sleep walking/talking
Outline Lewy body dementia
- dementia features early then Parkinsonian features
- caused by misfolding of alpha synuclein
- misfolded aggregate into Lewy bodies
- deposition into cortex (dementia type symptoms) + substantia nigra (Parkinsonian features)
Late symptoms of Lewy body dementia
Parkinsonian symptoms:
- bradykinesia
- resting tremor
- stiffness
Treatment of Lewy body dementia
Symptom based
Levodopa
What is frontotemporal lobe dementia?
Frontal + temporal lobe atrophy
Umbrella term for heterogeneous group of disease that can be characterised on the type of glial + neuronal proteinaceous inclusions or underlying genetic mutation
How does frontotemporal lobe dementia occur?
- aggregate proteins
- Tau protein hyperphosphorylation (Pick’s disease)
- frontal + temporal lobe atrophy
Symptoms of frontotemporal lobe dementia
- behavioural + emotional changes
- inappropriate social behaviour
- loss of motivation without depression
- broca type aphasia
How does AIDs dementia occur?
- occurs when CD4+ count falls below threshold
- entry of HIV infected macrophages into brain > inflammation + neuron damage
Clinical features of AIDs dementia
- congitive impairment
- psychomotor retardation
- tremor
- ataxia
- dysarthria
- Incontience
Outline vascular dementia
Cognitive impairment caused by cerebrovascular disease (multiple small strokes)
Risk factors for vascular dementia
- previous stroke or MI
- hypertension
- hypercholesteroaemia
- diabetes
- smoking
Difference between Parkinson’s disease + Lewy body dementia
- Parkinson’s disease: movement disorder followed by dementia
- Lewy body dementia: dementia followed by movement disorder (Parkinsonism)
Why should you not give anti-psychotics e.g. haloperidol in Lewy body dementia?
It can cause neuroleptic malignant syndrome
Features of neuroleptic malignant syndrome
Fever
Confusion
Tachycardia
Tachypnoea
Fluctuating BP
Elevated creatine phosphokinase
Rigidity
