Dementia: An Introduction

Description

  • neurodegenerative syndrome → progressive decline in several cognitive domains over months/years, usually signalled by memory loss
    • Cognition: the mental processes by which knowledge is acquired i.e. perception, reasoning, acts of creativity, problem-solving and possibly intuition

Subtypes

  • Alzheimer’s Disease
  • Vascular Dementia (25%)
    • cumulative effect of many small strokes
    • sudden onset and stepwise deterioration
    • Identify signs of ateriopathy: hypertension, focal CNS signs, past strokes
    • Avoid acetylcholinesterase inhibitors, memantine
  • Lewy Body Dementia (15-25%)
    •  fluctuating cognitive impairment
    • detailed visual hallucination followed by parkinsonism
    • Lewy bodies on histology in brainstem and neocortex
    • Avoid antipsychotics
  • Fronto-temporal dementia
    • loss of >70% of spindle neurons of in frontal and temporal lobes
    • executive impairment, behavioural/personality changes, disinhibition, hyperorality, stereotyped behaviour, emotional unconcern
    • Episodic memory + spatial orientation retained until later stages
    • Pick’s disease: few fronto-temporal dementia patients who have Pick inclusions on histology

Diagnosis

  • History (including collateral)
    • timeline and domain(s) of decline
    • Non-cognitive functions like agitation, aggression, apathy → late disease
  • Cognitive testing
    • MMSE (doesn’t test for frontal function, hence FAB must be conducted in conjunction)
    • Frontal Assessment Battery
    • MOCA
    • MSE to identify anxiety, depression, or hallucinations
  • Exam
    • Identify any physical causes i.e. for vascular dementia, parkinsonism
  • Medication review
    • As causing or contributing to symptoms

Differential Dx

  • Alcohol/drug abuse
  • repeated head trauma
  • pellagra
  • Whipple’s disease
  • Huntington’s
  • Parkinson’s
  • HIV
  • Cryptococcosis
  • Familial autosomal dominant Alzheimer’s
  • CADASIL
  • Depression
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