Dementia

Question 1

What is the most common initial presentation of a patient with dementia?

Answer 1

Memory loss over months or years

Question 2

How does age influence dementia incidence?

Answer 2

It is gradual and progressive with prevalence increasing with age

Question 3

What is the most common cause of dementia?

Answer 3

Alzheimers Disease

Question 4

Name causes of dementia

Answer 4

Alzhiemers disease - 50/75%
Vascular dementia - 20%
Dementia with Lewy body - 15-20%
Frontotemporal dementia - 2%

Question 5

Aetiology of AD?

Answer 5

Age - major risk factor
Genetics - small proportion are familial, linked to genetic mutations in amyloid precursor protein on chromosome 21.
CVD: smoking and DM are risk factors whereas exercise decreases risk
Depression
Educational attainment
Low social engagement and support
Others: head trauma, learning difficulties.

Question 6

Pathophysiology of AD? What are the 2 key pathological changes seen in AD?

Answer 6

Abnormal accumulation of AB amyloid and protein tau.
The brain has billions of neurons and the normal functioning of these neurons depends on surrounding supporting strucutres such as microtubules and protein tau which stabilises the microtubules.

2 key pathological changes:

1. senile plaques - deposits of beta amyloid
2. neurofibrillary tangles - aggregations of hyperphosphorylated tau proteins in the brain

Question 7

Why is the presence of SP and NFT characteristic of AD but not pathognomic? What is characteristic of AD?

Answer 7

SP and NFT can be seen in other neurodegenerative conditions, not just AD. Topographic location within the brain (hippocampus and medial temporal lobes) is characteristic of AD.

Question 8

In-vivo evidence of AD pathology?

Answer 8

Decreased b amyloid and increased T-tau or P-tau in CSF.

Increased tracer retention on amyloid PET.

Question 9

Which other condition does AD overlap with?

Answer 9

Parkinsons

• 25% of patients with AD develop parkinsonism
• 50% of patients with Parkinson’s develop AD after 65.

Question 10

Clinical features of dementia?

Answer 10

Cognitive impairment (memory loss, repetition errors, difficulty comprehending and making words)

Behavioural and psychological symptoms (agitation, emotional lability, depression, anxiety, sleep disturbance, social withdrawal)

Activities of daily living
(loss of independence, problems managing finances, problems with basic personal care)

Non-memory
(spatial orientation, problems dressing, language dysfunction, language impairment and recognising words)

Question 11

What things would exclude a diagnosis of typical AD?

Answer 11

sudden onset
early occurrence of gait disturbance, seizures
early hallucinations
cognitive fluctuations

Question 12

What other conditions can cause memory problems?

Answer 12

severe depression
severe cerebrovascular disease
toxic, inflammatory or metabolic disorders

Question 13

How is a diagnosis of AD made? (initial consultation and then investigations we can use)

Answer 13

• history from the patient
  cognitive testing (AMTS for eg)
• mental state exam to identify depression, anxiety, hallucinations
• examination for physical cause (risk factors for VD or Parkinsonism)
• medication review
• memory clinics

Investigations

• bloods (reversible causes: high TSH, low B12, low folate, low thiamine (eg. alcohol), low calcium)
• Neuroimaging (MRI to look for volume loss, focal loss of temporal lobe is very indicative of AD) - exclude causes such as brain tumours, subdural haematoma etc.
• amyloid imaging: CSF - amyloid decreases plus increased total tau and phosphorylated tau
• brain function (FDG PET) - glucose utilisation in brain (biparietal loss of glucose metabolism is indicative of AD)

Question 14

What are the 3 D’s for differentials of AD?

Answer 14

1. Depression (and other psychiatric disorders): psychosis can be a feature of dementia (depression can cause pseudodementia)
2. Drugs: consider drugs with anti-cholinergic effects (eg. anti-histamines, anti-psychotics and anti-epileptics)
3. Delirium: acute confusional state

Question 15

Features distinguishing depression from dementia?

Answer 15

Depression

• Onset and decline often rapid (trigger or life event)
• Subjective complaints of memory loss (obvious early on)
• Patients distress or unhappy and variability shown in cognitive performance with a lot of ‘i dont know’ answers to questions

Dementia

• Vague, insidious onset
• Unaware or attempt to hide problems and confusion in the evening
• Mood may be labile
• Cognitive performance is consistent and attempts all questions

Question 16

Management of AD?

Answer 16

MDT
Advanced care planning
Co-existing conditions such as depression and anxiety should be managed
Driving: DVLA
- remain socially active
- remain cognitively active
- control vascular risk factors
- safe guarding
- medications

Pharmacological

• Acetylcholine esterase inhibitors (more ACh kept in synaptic cleft)
• Anti-glutamate (keeps neurones healthy)

Question 17

5 things to do to reduce AD risk?

Answer 17

• healthy body weight
• healthy diet
• regular exercise
• low alcohol intake
• no smoking