This progressive syndrome encompasses several aetiologies, with multiple cognitive deficits:
- Visuospatial function
- Higher function/ planning
In addition, there may be hallucinations, confusion, aggressive or anxious behaviour, and depression.
- Alzheimers disease is the biggest cause, where β-Amyloid is deposited as amyloid plaques around neurones, and neurofibrillary tangles occur, ultimately leading to cell death. Alzheimers presents as prolonged, global impairment of the above domains. Alzheimers is progressive- initial memory loss may lead to mood changes, abnormal behaviour, or psychosis. These patients need specialist referral and management, including Acetylcholinesterase inhibitors such as Donepezil.
- Vascular dementia is the next commonest, and the deficits follow a series of micro-strokes-so the onset is sudden drops in function(as opposed to the above gradual decrease). Risk factors include known prior stroke, High BP, and focal neurological signs.
- Dementia with Lewy Bodies has a more dramatic presentation with elaborate visual hallucinations and fluctuating cognitive function. Other salient points include sleep disturbance and (mild) Parkinsonism.
- Other: Frontotemporal Dementia, Dementia with Huntington's Disease, Dementia with Parkinson's Disease.
- Memory loss (typically short term and then lose the most recent memories first such that patients can regress back to a time when they are younger)
- Behavioural changes (for example wandering)
- Early impaired smell, typically initially unilaterally
- Relentlessly and unforgivingly progressive
- Others include:
- Dyspraxia (including dressing dyspraxia where they put their clothes on in the wrong order)
- Psychotic symptoms
- Personality change
- Mood changes (especially labile mood)
- Preserved insight
- Stepwise progression (with each small infarct or hypoxic event there is a stepwise drop in functioning and ability)
- There may be other signs of cerebrovascular disease, and hypertension, it is typically more common in males and smokers
Lewy Body Dementia
- Prominent visual hallucinations
- A very fluctuating course, changes can be day to day and even hour to hour
- Phases which are almost delirium like (key differential in all dementia)
Lewy bodies are intracellular inclusions made of alpha synuclein.
Bear in mind that antipsychotics in Lewy body dementia worsen everything! And can cause drastic worsening of symptoms and depressed consciousness.