Dementia Flashcards
What is cognition?
Mental action of acquiring knowledge and understanding through thought, experience and sense
What processes does cognition encompass?
Attention, social functioning, language, memory and executive
What is the literal definition of dementia?
Undoing of the mind = generally progressive/persuasive and associated with neurodegeneration
What is needed to diagnose dementia?
Evidence of significant cognitive decline in at least one cognitive domain = cognitive deficits interfere with independence and can’t be explained by another process
What are the cognitive domains?
Attention, executive, learning and memory, perceptuo-motor, social cognition
What is the epidemiology of dementia?
Prevalence in >= 65 y/o = 670000 cases
Incidence in >= 65 y/o = 210000 new cases per year
What is the greatest risk factor for dementia?
Ageing
What do focal deficits depend on?
The area of the brain that has been affected
What are the acute cognitive disorders?
Focal injury to brain, transient global amnesia and transient epileptic amnesia
What are some examples of focal injuries to the brain?
Viral encephalitis, head injury, stroke
What are some features of viral encephalitis?
Memory and language affected
Behaviour change
Patient pyrexial and unwell
What are some features of a head injury?
Attention, memory and executive dysfunction
What are the clinical features of transient global amnesia?
Abrupt onset antegrade > retrograde amnesia (repetitive), preserved knowledge of self, transient changes in the hippocampus
What is the duration of transient global amnesia?
4-6hr duration (always <24hrs)
What is the epidemiology of transient global amnesia?
Patients >50 = generally in 70s
Triggering factors = emotion, changes in temperature
What are some features of transient epileptic amnesia?
Short lived = forgetful with repetitive questioning, can carry out complex activities with no recollection of events
What is transient epileptic amnesia associated with?
Temporal lobe seizures = 30% seizures not seen
Should respond to anti-epileptic medication
What are some causes of subacute cognitive disorders?
Toxins = alcohol, carbon monoxide Infection = HIV, syphilis Inflammatory = limbic encephalitis Neurodegeneration and mood disorders Metabolic and functional
What is functional cognitive impairment?
Everyday forgetfulness impacting on functioning = more extreme cases may result in fugue state
How do the symptoms vary in functional cognitive impairment?
They fluctuate = mismatch between symptoms and reported function
What may functional cognitive impairment be part of?
A generalised functional disorder = decreased concentration, attention and reaction time with subsequent memory difficulties
In what group of people is functional cognitive impairment more common in?
Those with previously good memories
How is functional cognitive impairment different from a mood disorder?
Functional cognitive impairment doesn’t have deficits in attention, executive function and memory
How is functional cognitive impairment treated?
Explanation +/- neuropsychology
What is the most common human prion disease?
Creutzfeldt-Jakob disease = misfolded PrPsc causes neurodegenerative proteinopathy
What are the four types of Creutzfeldt-Jakob disease?
Sporadic, variant, iatrogenic and genetic
What are some features of sporadic Creutzfeldt-Jakob disease?
Usually aged 60
Rapid onset dementia and neurological signs with myoclonus = lasts 4 months
Most common type and cause unknown
What are some features of variant Creutzfeldt-Jakob disease?
Usually aged 20 = due to exposure to BSE
Painful sensory disturbance and neuropsychiatric decline = lasts 14 months
Least common type
What are some features of iatrogenic Creutzfeldt-Jakob disease?
Usually aged 30 = lasts <2 years
Cerebellar or visual onset and multifocal neurological decline
What are some features of genetic Creutzfeldt-Jakob disease?
Occurs at any age = may mimic sporadic type GSS type = prolonged ataxic syndrome FFI type = insomnia Variable duration but usually <2years Due to mutation in PRNP
How is limbic encephalitis identified?
Inflammatory changes on MRI or in CSF
Antibodies identified in CSF or serum
What are some features of limbic encephalitis?
Short term memory deficits +/- seizures +/- behavioural changes
May be associated with underlying malignancy or autoimmune disease
How is limbic encephalitis treated?
Treat tumour and give immunosuppressants
What are the most common dementia syndromes?
Alzheimer’s disease, vascular dementia and mixed dementia
What is Alzheimer’s disease?
Neurodegenerative proteinopathy = extracellular amyloid plaques disrupt normal cell function and induce apoptosis
What occurs in Alzheimer’s disease?
Disruption of cholinergic pathways in the brain and spinal cord = intracellular neurofibrillary tangles disrupt cytoskeleton and cause cell death
What is the initial symptom of Alzheimer’s disease?
Generally forgetfulness
What lobes of the brain are affected by Alzheimer’s disease?
Degeneration of the medial hippocampus and later parietal lobes = forgetfulness then apraxia and visuospatial difficulties
What are some features of early onset Alzheimer’s disease?
Age <65, genetic influences, may be atypical presentation
What are some features of sporadic Alzheimer’s disease?
Age >65, more due to environmental influences, usually typical initial forgetfulness
What are the atypical presentations of Alzheimer’s disease?
Occur in 15%
Posterior cortical atrophy = visuospatial difficulty
Progressive primary aphasia = semantic, logopentic aphasia (repeating), non-fluent aphasia
What investigations may be done for Alzheimer’s disease?
MRI = atrophy of temporal/parietal lobes
SPECT = decreased tempoparietal metabolism
CSF = decreased amyloid:increased TAU ratio
Amyloid ligand imaging
How is Alzheimer’s disease treated?
Address vascular risk factor
Cholinesterase inhibitors = rivastigmine, galantamine
NMDA receptor blocker = memantine
When does frontotemporal dementia usually present?
Early onset dementia = most age <65
What is the pathogenesis of frontotemporal dementia?
Neurodegenerative proteinopathy = TAU-TDP43-ubiquitin
Protein aggregation causes cell damage
What are the three types of frontotemporal dementia?
Behavioural variant (60%), primary progressive aphasia, genetic cause (25%)
What are some features of frontotemporal dementia?
Early frontal features = disinhibition, apathy, loss of empathy, stereotypes/compulsive behaviours
Early loss of insight
May be part of MND-FTD spectrum
What investigations can be done for frontotemporal dementia?
MRI = atrophy of frontotemporal lobes SPECT = decreased frontotemporal metabolism CSF = increased TAU, normal amyloid
What is the treatment for frontotemporal dementia?
Trial trazadone or anti-psychotics
What age does vascular dementia present?
Late onset dementia = majority aged > 65
How is vascular dementia diagnosed?
Presence of cerebrovascular disease plus a clear temporal relationship between the onset of dementia and cerebrovascular disease
How can vascular dementia present?
Subcortical (small vessel) = decreased attention, executive dysfunction and slowed processing
Post stroke dementia = 25% develop vascular dementia <3 months after stroke
What pathology is associated with vascular dementia?
Co-existent amyloid pathology = slow disease progression
How is vascular dementia treated?
Manage vascular risk factors +/- cholinesterase inhibitor, CPN
When does Lewy body dementia present?
Late onset dementia = majority aged >65
What is the pathogenesis of Lewy body dementia?
Neurodegenerative pathology = alpha-synuclein aggregates are insoluble which leads to cell dysfunction and damage
What effect do alpha-synuclein aggregates have on brain pathways in Lewy body dementia?
Disrupt cholinergic and dopaminergic pathways
How does Lewy body dementia present?
Fluctuating cognition plus recurrent well formed hallucinations +/- presence of extrapyramidal features
May have additional neuroleptic sensitivity
What is the treatment for Lewy body and Parkinson’s disease dementia?
Small dose levodopa, decrease acetylcholine
What investigations cane be done for Lewy body dementia?
Dopamine transport imaging
Alpha-synuclein ligand imaging
When does Parkinson’s disease dementia present?
Late onset dementia = usually >65 years old
What does Parkinson’s disease dementia overlap with clinically?
Lewy body dementia
How does Parkinson’s disease dementia present?
Parkinson’s = bradykinesia, rigidity, tremor
Decreased attention, slowness of processing, impaired visuospatial function and memory, hallucinations
When does Huntington’s disease present?
Early onset dementia = mean age of onset is 30-50 years old
What causes Huntington’s disease?
Expansion of the CAG nucleotide repeat on huntingtin gene produces neurodegenerative protein
What is dementia?
Dysexecutive syndrome and slowed speed of processing = eventual involvement of memory
What are some features of Huntington’s disease?
Associated changes in mood, personality and chorea +/- later psychosis
What investigations are done for Huntington’s disease?
Genetic testing
MRI = loss of caudate heads
How is Huntington’s disease managed?
Mood stabilisers, drugs for chorea, HD nurse specialist
Who do you refer an >65 y/o with gradual onset dementia and no additional neurology to?
Old age psychiatry
Who do you refer an <65 y/o with additional neurology or any unusual features to?
Neurology
What are some features of the collateral history taken in the neurology memory clinic?
What were the first deficits?
What has happened since?
What are their functional difficulties?
How are patients assessed in the neurology memory clinic?
Cognitive assessment = Addenbrooke’s +/- FAB
Imaging = MRI, SPECT if MRI unrewarding
Bloods = B12, TFTs, syphilis, HIV, Ca2+ +/- genetic panel
