What are the diagnostic requirements for dementia?
Memory impairment for at least 6 months
Plus impairment in one or more of the following:
- Executive functioning eg logic, reasoning
- Language eg repeating
- Praxis - learned motor tasks
- Gnosis - recognising faces and objects
What are the 5 mains types of dementia?
- Alzheimers
- Vascular
- Lewy body
- Temporofrontal
- Other eg HD, CJD, HIV
What are some differential diagnosis for dementia?
- DEPRESSION - hard to differentiate sometimes
- Delirium eg infection, constipation, alcohol
- Mild cognitive impairment - doesnt affect activities of daily living
- Physical illness - Hypothyroid, thiamine deficiency, Wernickes, neoplasm, renal impairment and toxicity
What are the risk factors for Alzheimers Disease?
Female
Age
Genetics - Presenillin/Apolilipoprotein
What is the pathophysiogy of Alzheimers Disease??
- Amyloid cascade hypothesis - Insoluble amyloid plaques which are toxic to the brain aggregate - they come from Amyloid precursor protein (part of cell membrane).
- These encourage tau protein to form Neurofibrilliary tangles
- Cerebral cortex atrophy
- This all causes cerebral cortex atrophy and ACH disruption to amygdala and hippocampus and disrupts memory
What do neurofibrilliary tangles and senoid plaques look like?
How is Alzheimers Disease diagnosed?
What are the cardinal signs?
DIagnosis of exclusion
Insiduous, progressive, gradual decline
LOSS OF NEW MEMORIES
What are the risk factors for vascular dementia?
Age
male
Cardiovascular risk factors
What is the pathophysiology of vascular dementia??
Focal or widespread embolism causing cerebral infarction
What are the cardinal features of vascular dementia?
Abrupt onset
Stepwise decline
How is vascular dementia diagnosed?
Neurological signs and vascular disease on imaging
What is Dementia with Lewy bodies?
A continuum between Alzheimers and Parkinsons
What is the pathophysiology of Dementia with Lewy bodies?
Lewy bodies form in brain and affect dopaminergic and acetylcholinergic neurons
Dopamine - PD
ACH - Alzheimers
Both - Dementia with Lewy bodies
What are the diagnostic features of Dementia with Lewy bodies?
Dementia, plus two of the following
- Visual hallucinations
- Parkinsonism
- Reduced alertness
What is frontotemporal dementia?
Atrophy of frontal and temporal lobes
What is an example of frontotemporal dementia?
Picks Disease
What are the features and what is an example of frontotemporal dementia?
Early onset
Loss of language and personality/behaviour changes whilst memory remains intact
How is dementia assessed?
Mini mental state exam
CT brain - not diagnostic but can exclude other pathologies
What is a differential for dementia where the key symptom is urinary incontinence?
Hydrocephalus
