Dementia Flashcards
What is dementia?
An acquired impairment of higher mental functioning (intellect, memory personality) occurring in an alert patient. Usu progressive, very few cases are reversible.
Main features of dementia?
- Development of multiple cognitive deficits
- Condition sufficiently severe to cause impairment in function
- Chronic, progressive
- Cannot be diagnosed during delirium or depression
What are examples of the cognitive deficits of dementia?
Short term memory + one or more of:
- Aphasia (language disturbance)
- Apraxia
- Agnosia (object recognition)
- Executive function
Population diagnosed with dementia?
~8%
How does the prevalence and incidence of dementia change with ageing?
Prevalence and incidence double every 5 years after 60y. 20% over the age of 80 have dementia.
What conditions can resemble dementia?
- Normal changes with ageing
- MCI
- Delirium
- Depression
- Mild-mod intellectual disability
How does memory change in the elderly?
Normal decline in speed of processing, some decrease in recent memory.
Ax: stress, Rx, mood, pain, bereavement
What is MCI?
Memory and other cognitive complaints noted subjectively and objectively without apparent impact on general function.
What is the progression for individuals presenting with amnestic MCI?
Of pts p/w with prominent memory loss , over 50% will develop dementia in 5y
What are the common causes of dementia?
-Alzheimer’s (50-70%)
-Vascular (10-20%)
-Frontal lobe
-Lewy Body
=90% dementias
What are less common causes of dementia?
- Alcohol related
- Huntington’s
- Hydrocephalus
- Hypothyroidism
- B12 deficiency
- Neurosyphilis
What are the major proven RFx for AD?
- Age
- Down syndrome
- Genetic predisposition (APOE)
- Ethinicity
Which gene is associated with AD?
APO E4
What are the other RFx for AD?
- HTN
- DM
- Hyperlipidemia
- Smoking
- Obesity
- Significant head injury
- Nutritional (on top of vascular RF modification effect): ?fish, ?mediterranena diet ?fruti and vegie
What are AD protective factors?
- Education
- Physical activity
- Social engagement
- Cognitive activity
Time course of AD?
Insidiously progressive
- gradual onset
- steady worsening
Main features affected AD?
- New learning (amnestic features)
- Praxis
- Language
Neuro exam AD?
Normal until late stages
Structural imaging AD?
Often normal;
-may have some degree of atrophy esp hippocampus and adjacent
What pharm can be used in AD?
Cholinesterase inhibitors e.g. donepezil, galantamine, rivastigmine
Success of AD pharm Rx?
Benefits modest, 30-60% show clinical benefit.
Aim to delay progress and improve function.
Major features of vascular dementia?
- focal neuro signs
- attention, exec fun affected
- insight preserved
- radiol shows infarction
- Sudden onset, stepwise progression
- Overactive bladder and disturbance of gait common early signs
What affects VD presentation?
Location of lesions i.e. subcortical changes produce executive function changes often a/w gait disturbance and incontinence
How does fronto temporal dementia present?
- Early: behavioural changes
- Executive dysfunction
- Language disturbance (poor verbal fluency)
Why are cognitive assessments different in frontotemporal dementia?
New learning is preserved until later so MMSE etc may be normal as no frontal functions tested
Imaging in fronto temporal dementia?
- FT brain atrophy
- Functional: decreased frontal perfusion
What characterises Lewy body dementia?
- fluctuating attention and concentration
- detailed visual hallucinations
- parkinsonism within 1y of cognitive onset
What should be covered in dementia clinical assessment?
- General medical (inc RFx and CV assessment)
- Neuro Hx and PEx
- Meds (esp anticholinergics, sedatives)
- FHx, esp in those with younger onset dementias
- Neuropsychiatric Hx inc behavioural disturbances
- A careful description of onset and progression of disease. (Supplemented by carer or informant)
- Functional status inc driving, at home safety, medications
- legal: ACP, EPOA, finances
Disadvantages MMSE?
- lack of testing of executive function (i.e. frontal lobe)
- education, language and cultural bias
- high ceiling effect
- requires copyright
What are the Ix of dementia workup?
-FBE/LFT/UEC/ESR
-CMP
-TFTs
-B12 / folate
-MRI/PET
Other as required e.g. syphilis, EEG, UA.
Referrals in new dementia diagnosis?
- ACAS
- Alzheimer’s Australia (for carers and families)
Which areas are affected by AD?
- Temporoparitetal CORTICAL areas
- Hippocampal and mesial temporal areas
AD average survival?
8-10y
Why are people with Down Syndrome at risk of AD?
Amyloid Precursor Protein gene on Chr21 (therefore get 3x copies)
Pathophysiology of AD?
- Neuritic Plaques
- Neurofibrillary Tangles
- Neurotransmitter defects (lost 90% ACh in adv AD)
What are neuritic plaques?
Form outside neurons; spherical bodies composed of Beta amyloid
What are neurofibrillary tangles?
Form inside neurons from hyperphosphorylated tau
Pathophysiology of Lewy Body Dementia?
- Loss of cholinergic function: cognitive issues
- Loss of dopiminergic function: parkinsonism
- Lewy Bodies: proteinaceous (alpha-synuclein) cytoplasmic inclusions(stain for ubiquitin)- in the brainstem, subcortex and cortex. Sparing of medial temporal lobes.
- Has amyloid protein, but much fewer neurofibrillary tangles
What other conditions are a/w FT dementia?
- MND
- Corticobasal degeneration
- Progressive supranuclear palsy
What is the aim of CTB in dementia work up?
- Exclude mass lesions
- Subdural haematomas
- NPH
- Large vascular lesions
What is the mainstay of dementia Mx?
Non drug Rx i.e. planning, risk modification, education.
What are the risks that should be addressed in dementia management?
-Medication compliance
-Adequate nutrition
-Home modifications- change stove/ car keys etc
Identity cards/ bracelets
-Driving assessment
-Awareness of abuse/ neglect
