Dementia

Question 1

What is Dementia?

Answer 1

Clinical syndrome caused by a number of brain disorders which cause memory loss, decline in other aspects of cognition and difficulties with activities of daily living.

Question 2

Common causes of dementia?

Answer 2

• Alzheimer’s disease (most common cause)
• Vascular dementia (accounts for 25%)
• Dementia with lewy bodies
• Frontotemporal dementias
• Potentially treatable dementias

Question 3

What is Alzheimer’s disease?

Answer 3

Most common cause of dementia. occurs in 50-70% of cases.

Question 4

What is vascular dementia?

Answer 4

Brain damage due to cerebrovascular disease, either major stroke, multiple smaller unrecognised strokes (multi-infarct) or chronic changes in smaller vessels (subcortical dementia).

Question 5

What is dementia with lewy bodies?

Answer 5

Occurs for 15% of cases. It is the deposition of abnormal protein (alpha-synuclein) within neurons of the brainstem and neocortex.

Question 6

What is frontotemporal dementia?

Answer 6

Accounts for less than 5% of cases. It has a strong association with MND (particularly ALS - the most common).

Results in specific degeneration/atrophy of the frontal and temporal lobes of brain.

Question 7

Some causes of potentially treatable dementias (<5% of cases)?

Answer 7

• Metabolic e.g. uraemia
• Toxic e.g. alcohol
• Vitamin deficiency - B12 and thiamine
• Traumatic - severe or repeated brain injury
• Infections e.g. HIV
• Intracranial lesions e.g. subdural haematoma, tumours
• Endocrine e.g. hypothyroidism
• Psychiatric - depression causing “pseudodementia”.

Question 8

Rare causes of dementia and what is inheritance pattern?

Answer 8

Huntington’s disease
- Autosomal dominant trait
- Usually presenting between 30 to 50 years of age (but can vary).

Question 9

What are the pathological hallmarks of Alzheimer’s disease?

Answer 9

• Loss of cortical neurones
• Neurofibrillary tangles - abnormal accumulations of a protein called tau that collect inside neurons.
• Senile plaques - extracellular proteins deposits containing amyloid beta protein. Found in the brain during Alzheimer’s disease and normal ageing.

Question 10

Initial symptom of Alzheimer’s disease?

Answer 10

Usually forgetfulness

Question 11

What genetic mutation occurs for huntington’s disease?

Answer 11

CAG repeat encoding poly-glutamine – has a toxic effect on cells leading to neuronal loss.

Question 12

Caudate atrophy occurs with huntington’s disease. True/false?

Answer 12

True

Question 13

What is caudate atrophy?

Answer 13

Loss of cells from the basal ganglia causing flattening of the normal convex curve of the lateral ventricles.

Question 14

Clinical presentation of Alzheimer’s disease?

Answer 14

• Gradual onset, decline of particularly short-term memory.
• Autobiographical and political memory is well preserved.
• Poor concentration, poor sleep and low mood.
• Personality changes – disinhibited, lack of self-care.
• In end stages — hallucinations, poor dentitition, skin ulcers and loss of verbal communication.

Question 15

Clinical presentation of vascular dementia?

Answer 15

Dysphasia, dyscalculia, frontal lobe symptoms.

Possible vascular risk factors

May have step wise decline

Question 16

How many variants (syndromes) with frontotemporal dementia?

Answer 16

3 syndromes

Question 17

Clinical presentation of frontotemporal dementia - what are the different syndromes?

Answer 17

Behavioural variant - behavioural changes, impulsivity, loss of social skills, apathy, obsessions and changes in diet.

Primary progressive aphasia - effortful non - fluent speech, speech errors, lack of grammar and lack of words.

Semantic dementia - impaired understanding of meaning of word, fluent but empty speech and difficulty retrieving names.

Question 18

Clinical presentation for dementia with lewy bodies?

Answer 18

Dementia - common early involvement of reduced attention.

2 of:
- Visual hallucinations
- REM sleep behaviour disorder
- Extrapyramidal features (Parkinsonism) seen in 75%.

Question 19

Clinical presentation for dementia in Parkinson’s disease?

Answer 19

80% after 15 - 20 years of Parkinson’s disease.

Must have Parkinsonism for at least 1 year prior to onset of dementia.

Clinical presentation is similar to dementia with Lewy Bodies.

Question 20

Diagnostic criteria for dementia?

Answer 20

History consistent with global cognitive decline over months - year.

Decline in function level

No evidence of reversible cause

Question 21

Imaging for dementia?

Answer 21

CT is currently standard.

MRI if young patient, fast progression or other atypical features.

Question 22

Management of dementia?

Answer 22

Dementia cases are rarely reversible so management is supportive (treat the symptoms).

Vascular dementia: vascular risk factors +/- cholinesterase inhibitor.

Frontotemporal dementia: trial of trazadone/antipsychotics for behavioural features.
Safety management - controlled access to food/money/internet, other structured activities.

Dementia with lewy bodies:
- Small dose levodopa
- Trial cholinersterase inhibitors - rivastigmine.