Dementia Flashcards
Define
• A chronic and progressive deterioration of cognitive function due to organic brain disease. It is irreversible and consciousness is not impaired.
What are the types of dementia?
o Alzheimer’s disease (50%) - degeneration of the cerebral cortex, with cortical atrophy and reduction in acetylcholine production
o Vascular Dementia (25%) - brain damage due to several incidents of cerebrovascular disease (e.g. strokes/TIAs)
o Lewy Body Dementia (15%) - deposition of abnormal proteins (Lewy bodies) within the brain stem and neocortex
o Frontotemporal Dementia - specific degeneration of the frontal and temporal lobes
What are some other causes of dementia?
Vitamin B12 deficiency, hypothyroidism, intracranial mass, chronic traumatic encephalopathy, infections (HIV, neurosyphilis), Huntington’s and Parkinson’s.
Epidemiology
- Prevalence increases with age
* Prevalence of 20% in patients aged > 80 yrs
What are the presenting symptoms of Alzeihmars?
o Short-term memory loss (early symptom)
o Slow disintegration of personality and intellect eventually affecting all cortical functions. There is decline in language (difficulty in naming and in understanding what is being said), visuospacial skills, apraxia (impaired ability to carry out skilled motor tasks) and agnosia (failure to recognize objects, e.g. clothing, people, places).
What are the presenting symptoms of vascular dementia?
• Vascular dementia - step-wise decline and stability
WHat are the presenting symptoms of Lewy body dementia?
fluctuating levels of consciousness, HALLUCINATIONS and sleep disorders, falls and Parkinsonian symptoms
What are the presenting symptoms of frontotemporal dementia?
behavioural changes and intellectual changes
What are the appropriate investigations?
• Diagnosis is based on the HISTORY
• Ensure no treatable cause is missed (e.g. hypothyroidism, vitamin B12/folate deficiency, space-occupying lesion, normal pressure hydrocephalus)
• A CT scan in younger patients. MRI shows atrophy
• The mini mental state examination (MMSE) used – 25/30 normal, 18-24/30 (mild to moderate impairment) and below 17 (severe impairment).
• Abbreviated mental test score:
o Age, time, address, year, place, recognition of two people, DOB, year of WW1, name of present monarch, count backwards 20-1, address recall correct? – each correct answer scores 1 mark.
What questions would you ask on the abbreviated mental test score?
o Age, time, address, year, place, recognition of two people, DOB, year of WW1, name of present monarch, count backwards 20-1, address recall correct? – each correct answer scores 1 mark.
What are some general clinical symptoms of dementia?
Memory loss – especially recently acquired information
Disorientation/ confusion – forgetting where they are
Language problems – stopping in the middle of a conversation
Personality changes – becoming confused, fearful, anxious
Poor judgement – such as when dealing with money
Explain the pathophysiology
Beta-amyloid theory - Accumulation of beta-amyloid plaques, toxic
Tau theory - hyperphosphorylated tau is insoluble, self-aggregates to form neurofibrillary tangles which are neurotoxic, microtubule instability in axons
Inflammation theory -
inappropriate activation of microglial cells (specialised CNS immune cells)
What drugs used to treat AD?
- Anticholinesterases
- Donepezil
Reversible cholinesterase inhibitor.
Long plasma half-life – once a day
- Rivastigmine
Pseudo-reversible AChE & BChE inhibitor
8 hour half-life
Reformulated as transdermal patch - Galantamine
Reversible cholinesterase inhibitor
7-8 hour half-life
7 nAChR agonist
- NMDA receptor blocker
- Memantine
Use-dependent non-competitive NMDA receptor blocker with low channel affinity
Only licensed for moderate-severe AD
Long plasma half-life
