Dementia Flashcards
What is the most common initial presentation of a patient with dementia?
Memory loss over months or years
How does age influence dementia incidence?
It is gradual and progressive with prevalence increasing with age
What is the most common cause of dementia?
Alzheimers Disease
Name causes of dementia
Alzhiemers disease - 50/75%
Vascular dementia - 20%
Dementia with Lewy body - 15-20%
Frontotemporal dementia - 2%
Aetiology of AD?
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.
Pathophysiology of AD? What are the 2 key pathological changes seen in AD?
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:
- senile plaques - deposits of beta amyloid
- neurofibrillary tangles - aggregations of hyperphosphorylated tau proteins in the brain
Why is the presence of SP and NFT characteristic of AD but not pathognomic? What is characteristic of AD?
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.
In-vivo evidence of AD pathology?
Decreased b amyloid and increased T-tau or P-tau in CSF.
Increased tracer retention on amyloid PET.
Which other condition does AD overlap with?
Parkinsons
- 25% of patients with AD develop parkinsonism
- 50% of patients with Parkinson’s develop AD after 65.
Clinical features of dementia?
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)
What things would exclude a diagnosis of typical AD?
sudden onset
early occurrence of gait disturbance, seizures
early hallucinations
cognitive fluctuations
What other conditions can cause memory problems?
severe depression
severe cerebrovascular disease
toxic, inflammatory or metabolic disorders
How is a diagnosis of AD made? (initial consultation and then investigations we can use)
- 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)
What are the 3 D’s for differentials of AD?
- Depression (and other psychiatric disorders): psychosis can be a feature of dementia (depression can cause pseudodementia)
- Drugs: consider drugs with anti-cholinergic effects (eg. anti-histamines, anti-psychotics and anti-epileptics)
- Delirium: acute confusional state
Features distinguishing depression from dementia?
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
Management of AD?
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)
5 things to do to reduce AD risk?
- healthy body weight
- healthy diet
- regular exercise
- low alcohol intake
- no smoking