9. Dementia

Question 1

What is dementia?

Answer 1

• Progressive decline in higher cortical function…
• leading to a global impairment of MEMORY, INTELLECT and PERSONALITY…
• which affects the individual’s ability to cope with activities of daily living.

Question 2

How is dementia different from delirium?

Answer 2

Dementia = no impairment of consciousness

Delirium = impaired consciousness

Question 3

Name the 4 main types of dementia and describe their typical onset/progression.

Answer 3

1. Alzheimer’s disease (60%): gradual, progressive onset and decline
2. Vascular dementia (20%): abrupt or gradual onset, with step-wise decline (related to vascular episodes)
3. Lewy body dementia (4%): insidious onset with progressive but fluctuating decline (periods of remission)
4. Fronto-temporal dementia (2%): insidious onset, rapid progression

Question 4

Describe the typical features of Alzheimer’s disease.

Answer 4

1. memory loss, esp. names and recent events
2. language deficits
3. impaired visuospatial skills
4. later affective/behavioural symptoms, e.g. aggression

Question 5

Describe the typical features of Lewy Body dementia.

Answer 5

1. fluctuant cognitive impairment
2. visual hallucinations
3. Parkinsonism: shuffling gait, increased tone, tremors, falls

Question 6

Describe the typical features of frontotemporal dementia.

Answer 6

1. altered social behaviour and personality, e.g. depression, agitation
2. impaired judgement and insight, e.g. disinhibition
3. apathy, poor executive function
4. speech output falls eventually to state of mutism

Question 7

Describe the typical features of vascular dementia.

Answer 7

Depends on area of brain affected by ischaemia and if acute/chronic ischaemia but can include:

• confusion and disorientation
• dysphasia
• vision loss

Question 8

Explain the pathophysiology of Alzheimer’s.

Answer 8

Accelerated cortical neurone loss causing generalised cortical atrophy (narrowed gyri and wide sulci) due to formation of:

1. amyloid-beta plaques: incomplete breakdown of amyloid precursor protein… AB monomers aggregate to form extra-neuronal plaques… deposit at dendrites, affecting neuronal signalling and promoting inflammatory resp., and deposit in local blood vessels
2. neurofibrillary tangles: Tau protein (normally binds and stabilises microtubules) hyperphosphorylation… form intracellular twisted filaments

Question 9

Describe the pathophysiology of vascular dementia

Answer 9

Neuronal ischaemia/damage due to:

1. arteriosclerosis of cerebral arteries
2. multiple small ischaemic/haemorrhagic strokes, inc. lacunar infarcts
3. cerebral small vessel disease, e.g. diabetes mellitus

Question 10

Describe the pathophysiology of Lewy body dementia.

Answer 10

Intracellular accumulation of Lewy bodies (abnormal protein inclusions) throughout cortex and substantia nigra.

Question 11

Describe the pathophysiology of frontotemporal dementia.

Answer 11

Diverse group of conditions with similar presentations but different pathologies:

1. frontotemporal lobar degeneration
2. Pick’s disease (build-up of Tau proteins forming Pick bodies)
3. familial tauopathies

Question 12

Name a rare cause of dementia.

Answer 12

Creutzfeldt-Jacob disease

Question 13

Name 5 possible reversible causes of dementia.

Answer 13

1. depression
2. trauma
3. vitamin deficiency (eg VitB12)
4. alcohol
5. thyroid disorders

Question 14

What is delirium/ How can dementia be differentiated from this?

Answer 14

Delirium = sudden onset/acute state of confusion precipitated by e.g. infection, severe pain, constipation…

Use CAM score (confusion assessment method) - likely delirium if 2+ of:

• acute change or fluctuating mental status
• altered consicousness (hypo/hyperactive)
• inattention (ask to count back from 20)
• disorganised thinking