Dementia

Question 1

What is the epidemiology of dementia?

Answer 1

Rare under 55yrs then increasingly common from then on
850,000 in UK in 2015, predicted >1 million by 2025
Alzheimer’s is the most common form

Question 2

What is the aetiology and pathophysiology of Alzheimer’s disease?

Answer 2

May appear from 40yrs; even earlier in Down’s syndrome (inevitable)

Environmental and genetic factors

i) 1st degree relative
ii) Down’s
iii) Homozygosity for apolipoprotein e (Apoe) allele
iv) Vascular risk factors – raised BP, diabetes, hyperlipidaemia
v) Low physical/cognitive activity
vi) Depression and loneliness
vii) Smoking

Accumulation of ß-amyloid peptide (a degradation of amyloid protein) → progressive neuronal damage, neurofibrillary tangles, plaque formation, loss of ACh

i) Partly due to altered macrophage gene expression → reduced effective clearance
ii) Selective neuronal loss - hippocampus, amygdala, temporal neocortex
iii) Also show evidence of vascular dementia

Question 3

What is the aetiology and pathophysiology of vascular dementia?

Answer 3

25% of all dementias
Represents the cumulative effect of many small strokes → sudden onset and stepwise deterioration is characteristic
Look for evidence of vascular pathology i.e. raised BP, past stroke, focal CNS signs

(Will not likely present with hallucinations)

Question 4

What is the aetiology and pathophysiology of Lewy body dementia?

Answer 4

Characterised by histological presence of Lewy bodies in brainstem and neocortex (abnormal aggregates of protein)

Question 5

What is the aetiology and pathophysiology of Fronto-temporal (Pick’s) dementia?

Answer 5

Frontal + temporal atrophy without Alzheimer’s histology

Genes on ch9 are important (as in MND)

Question 6

What are some other aetiologies of dementia?

Answer 6

Alcohol/drug abuse 
Repeated head trauma 
Pellagra
Whipples disease 
Huntingtons 
CJD 
Parkinson’s 
HIV

Question 7

What’s the general presentation of all dementia’s?

Answer 7

Memory loss – over months/years (if hours = stroke, weeks = depression?)
Other cognitive function decline
Agitation, aggression, apathy

Question 8

What is the presentation of Alzheimer’s disease?

Answer 8

Enduing progressive global cognitive impairment (other dementias are more focal) – reduction in visuospatial skills, memory, verbal abilities, executive function Anosognosia – lack of insight into the problems caused by the disease i.e. missed appointments, misunderstood conversations etc
Irritability, mood disturbance – euphoria, depression
Behavioural change – wandering, aggression
Psychosis – hallucination, delusion
Agnosia – cant recognise things, even self
Become sedentary in end stage

Question 9

What is the presentation of Lewy body dementia?

Answer 9

Fluctuating cognitive impairment
Detailed visual hallucinations i.e. small animals or children
Parkinsonism

Question 10

What is the presentation of Fronto-temporal dementia?

Answer 10

Also known as Pick’s disease

More common in those under 65yrs

Executive impairment
Behavioural/personality change
Early preservation of episodic memory and spatial orientation
Disinhibition - may seem like a bipolar manic presentation
Stereotyped behaviour
Emotional unconcern
Hyper-orality
Inability to produce speech and loss of literacy (primary progressive aphasia type)

Question 11

How do you investigate dementia?

Answer 11

Good history from patient and family/friends etc -
timeline of symptoms established, failure to function?
Cognitive testing - AMTS or TYM, Mental state examination
Bloods, CT/MRI, ECG, genetics etc - to check for any potential remediable aetiologies

Question 12

How do you manage dementia?

Answer 12

Incurable – progressive and terminal

Coordinated care with an MDT and family - Capacity? Future decisions? Plan ahead
Routines
Care for carers
Admiral nurses

Challenging behaviour or severe distress

i) Lorazepam
ii) Antipsychotics (though not for Lewy body or if Hx of Parkinson’s)

Antidepressants:
But not for mild/moderate depression
SSRIs are associated with hyponatraemia in the elderly = risky
Stop TCAs - can worsen cognitive impairment

Acetylcholinesterase inhibitors

i) Donepezil (not in those with bradycardia), Rivastigmine, Galantamine
ii) May improve some symptoms – help laying down of new memories rather than retention of old and delay need for institutional care

2nd line:
Memantine - an NDMA antagonist
For moderate Alzheimer’s in those who acetylcholinesterase inhibitors are contraindicated
Or as an adjunct to the above
Or in severe Alzheimer’s as a monotherapy