Alzheimer's Dementia Flashcards
If a patient with a history of dementia or consistent with dementia presents with acute or subacute irritability and confusion, you want to screen for. . .
. . . presence of a UTI
Dementia, by definition
Decline in memory and at least one other cognitive domain (orientation, language, praxis, visuospatial, judgement) that is severe enough to interfere with daily function and independence
1, #2, and #3 causes of acute worsening of symptoms / superimposed delirium in a patient with dementia
1: Infection
Five most common dementia syndromes
- Alzheimer’s disease
- Lewy body dementia
- Vascular dementia
- Frontotemporal dementia
- Late-stage Parkinson’s disease
Dementia + visual hallucinations is a smoking gun for. . .
. . . Lewy body dementia
Predominant deficits in Alzheimer’s
Memory and visuospatial function (including praxis and cognitive mapping)
Paraphasic errors
Production of unintended syllables, wrods, or phrases during speech
Nucleus Basalis of Meynert
Goup of nerves with wide projections into the neurocortex, rich in acetylcholine and choline acetyltransferase
Alzheimer’s Disease
- Leading cause of dementia
- Diffuse cortical atrophy and hippocampal atrophy with ventricular enlargement, often with atrophy of the nucleus basalis
- Etiology: 90% idiopathic, 10% mutation in presenilin-1 or presenilin-2
- Often presents with recent memory loss and visuospatial deficits (forgetting how to navigate common areas, apraxia). Acalculia is also common.
- Often report inability to use common household items due to apraxia (vacuum, telephone, remote control, oven)
- Pathology: Neurofibrillary tangles, amyloid deposition
- Diagnosis: Clinical, but tests may support
Neurofibrillary tangles
“Cortical” vs “Subcortical” dementias
- Cortical dementias: Involve direct damage to and atrophy of various areas of the cerebral cortex. Tend to have involvement of cognitive functions while basic neurologic function is preserved.
- Ex: Alzheimer’s, Frontotemporal dementia
- Subcortical dementias: Characterized by attention and processing speed deficiencies with preservation of core cognitive functions. Damage is to the axons or basal ganglia rather than to the cell bodies in the cortex.
- Ex: Parkinson’s dementia, Huntington’s disease, Creutzfeldt-Jakob disease, CBD, PSP, HIV-induced dementia (aka HAND)
- Both:
- Lewy body dementia has features of both cortical and subcortical dementias, and vascular dementia depends entirely upon where the infarcts are
Frontotemporal dementia
- Presentaiton: Early loss of “social graces” (behavior, attention, executive function) while memory and intellectual function are relatively preserved or decline at a slower rate
- MRI: Selective atrophy of frontal and temporal cortex
- FTD patients sometimes present with a primary progressive aphasia due to damage to Broca’s area (frontal lobe) or Wernicke’s area (temporal lobe)
- Presentation called “semantic dementia”
Major cortical patterns in Alzheimer’s, FTD, and Lewy body dementia
- Alzheimer’s: Parietal lobe and temporal lobe (especially hippocampus)
- FTD: Frontal lobe and temporal lobe (relatively preserving hippocampus)
- Lewy body dementia: Occipital lobe, and less parietal and temporal lobes
DDx for subcortical dementia
- Parkinson’s dementia,
-
Parkinson’s Plus syndromes (CBD, PSP, Lewy body dementia)
- Note: LBD may have cortical features too
- Huntington’s disease,
- Creutzfeldt-Jakob disease,
- HIV-induced dementia (aka HAND)
- Normal pressure hydrocephalus
- Sometimes vascular dementia (depends where the infarcts are!)
- Binswanger disease
Binswanger disease
Subcortical dementia which develops due to chronic, untreated hypertension
Long-standing hypertension causes diffuse sub-cortical white matter changes that manifest as insidious subcortical function loss
