Differential diagnosis of dementia Flashcards
What is Charles Bonnet Syndrome (CBS)?
Complex visual hallucinations in indivduals w/ acquired visual loss with insight and without cognitive impairment (10-60%)
[high incidence of non reporting + diagnosis of exclusion]
Common characteristics of CBS?
- Simple geometric shapes
- Complex shapes with reconisable forms (faces, objects)
- Tessellopsia (regular, overlapping patterns)
- Prosometamorphopsia (facial distorsion)
- Dendropsia (branching forms)
- Hyperchromatopsia (all objects appear coloured)
- Polyopia (multiple forms of one image)
- Micropsia (objects appear smaller than normal)
- Macropsia
General features of the nature of dementia presentation
- no implied aetiology
- insidious onset, progressive decline
- clear consciousness
- deficits in behaviour, attention, memory, language, visuospatial dys
- reversible/irreversible; indolent/rapid progress; multiple def/isolated def
1st and 2nd most common dementia forms?
- AD
- DLB (and PDD)
[there is also vasc. dement and FTD)
How to definitively diagnose dementia?
Brain tissue required (biopsy)
Features that should be preserved w/ ageing?
- Temporal Orientation
- Immediate Attention
- Vocabulary
- Visuospatial skills
- Judgement & Insight
Features that suffer mild decrements w/ ageing
- Sustained Attention
- Visual > Verbal recall
- Naming
- Response speed
- Flexibility
What is Mild Cognitive Impairement (MCI)?
Cognitive impairment that is insufficient to reach criterion of “dementia”
Amnestic/non-amnestic
10-15% annually convert to dementia
NB: rule out psyc/drug/other
Features of Depressive Pseudodementia (DPD)?
- apathy
- social withdrawal
- mutism
- incontinence
- lack of “sadness”
[depression is misdiagnosed as dementia in 8-15% of mentally declining pts]
NB: depression is present in 20-30% of demented pts
Clues of DPD?
- FHx
- subacute onset
- agitation/pacing
- precipitants
- poor memory
- poor effort
- spared language + praxis
- normal EEG/imaging
What is Balint’s syndrome
[focal lesion]
Unable to perceive visual field as a whole:
- occulomotor apraxia
- optic ataxia
- visual stimultagnosia
What is Gerstmann’s syndrome?
[focal lesion]
- dysgraphia/agraphia
- acalculia
- finger agnosia
- unable to distinguish R/L side of body
Types of anatomical classification of dementia pathology?
- subcortical
- cortical
Describe subcortical features of dementia?
- slow, inefficient
- apathy, mood, personality
- motor signs
[e.g. PDD, huntingtons, PSP, MS, Wilson’s, HIV)
Describe cortical features of dementia?
- language
- praxis (visuospatial)
- disinhibition
- (memory)
[e.g. AD, FTD, DLC, CJD]
Describe feature of delirium?
Impaired stream of though and cognitive deficits
Diagnose:
Insidious amnesia, language impairment (anomia, paraphrasias, poor comprehension): ?
Lack of hygiene, personality change, poor comportment & planning: ?
Fluctuation, agitation, hallucinations, visuospatial dysfunction, Parkinsonism, neuroleptic sensitivity: ?
AD
FTD
DLB
Diagnose:
Memory loss, Ataxia, Incontinence: ?
Stepwise decline, focal/motor/gait signs: ?
Subacute or rapid decline,motor signs: ?
Normal Pressure Hydrocephalus (NPH)
Multi-Infarct Dementia (MID)
CJD/Autoimmune
Potential differentials for dementia symptoms?
- normal ageing
- psych disease (depress-pseudo dem, depression)
- drug
- focal neuro syndromes (aphasia, anomia, amnesia etc)
- acute confusional states (delirium)
- MCI (amnestic vs non-amnestic)
- MS
- Charles Bonnet Syndrome
Ddx of visual hallucinations?
- neurological (PD, LBD, epilepsy)
- psychiatric (schizophrenia)
- drugs
- sleep deprivation
Investigations for dementia symptoms?
- history
- neuro exam (dementia is a clinical diagnosis)
- biomarkers (CSF tau, CSF amyloid)
- EEG (slow wave activity in dementia due to increased delta waves)
- imaging (CT, MRI, PET, SPECT)
- brain biopsy (definitive)
Types of management for dementia?
Symptomatic treatment (no treatments that can halt progression)
Categories of dementia
- neurodegenerative
- traumatic/structural
- vascular
- metabolic
- toxic
- psychiatric
List some forms of neurodegenerative dementia?
- AD
- LBD
- PDD
- PSP/CBD
- FTLD
Forms of traumatic/structural dementia?
- subdural haematoma
- head injury (CTE, DAI, cerebral contusions)
- NPH (normal pressure hydrocephalus)
- neoplasm
Forms of vascular dementia?
- multi-infarct dementia
- cerebral amyloid angiopathy
- vasculitis (Wegner’s)
Metabolic causes of dementia?
- hypoxia/hypercapnia
- uraemia
- hepatic encephalopathy
- thiamine/B12 deficiency
- hypoglycaemia
Toxic causes of dementia?
- medication (Anticholinergic, valproate)
- alcohol
- carbon monoxide
Psychiatric causes of dementia?
- schizophrenia
- depression (pseudodementia)
- bipolar disorder
How to differentiate normal ageing from dementia?
Normal ageing has:
- preserved temporal orientation
- preserved visuospatial skills
- preserved judgement
- can give immediate attention when asked
