Dementia Flashcards
What are the most common causes/types of dementia?
Alzheimer's Vascular dementia Medicine/substance induced Reversible - appx15% due to vitamin b12 def, metabolic disorders,hypothyroidism. Tumours/trauma
Clear increase with age
What is dementia?
Dementia is the most common neurological disease.
Progressive, usually irreversible congnitive disease.
Initial worsening of memory
Degeneration of brain, including personality.
Hallucinations
Anxiety and depression
What is Alzheimer’s disease?
Most common form of progressive dementia, mostly in individuals over the age of 65.
Causing destruction of neurones, and normally causes death within 7 to 10 years.
Not normal ageing.
What are the risk factors in Alzheimer’s ?
Advanced age Some genetic component Some other diseases such as Down's syndrome Head trauma Blood supply to brain disruption Slightly higher risk in women Environmental inputs
What areas of the brain are most affected by Alzheimer’s?
Cerebral cortex - conscious thought and language
Basal forebrain - memory and learning
Hippocampus - essential for memory storage.
What can a PET show in Alzheimer’s?
Shows areas that are inactive, ie areas affected.
How can dementia/Alzheimer’s be diagnosed?
Cognitive testing
Mini mental state exams
Lab test for metabolic disorder
History
Exclude depression, not confuse lack of engagement with lack of memory.
MRI can be used in suspected vascular dementia.
A proper diagnosis can only be completed post Mortem as it required examination of the brain.
What causes the neuronal loss in Alzheimer’s?
Loss of cholinergic neurons
Amyloid plaques - abnormal deposits of protein outside cells
Neurofibrillary tangles - unusual structures within the cells.
What are the possible theory’s about what causes the cell death in Alzheimer’s?
Increased free radicals Aggregated b amyloid Inappropriate cell signalling Incorrect intracellular ions Head trauma
What is the amyloid hypothesis?
Generation of amyloid is central to disorder
Risk factors influence deposition of amyloid
Amyloid is somehow the cause of the tangles.
To do with cleavage of protein, certain sizes cause amyloid build up
Causative or indicative?
What is the importance of acetylcholine in dementia?
Direct correlations between cognitive impairment and cholinergic loss.
Lesions of cholinergic activity in hippocampus leads to learning and memory deficits.
Therefore drugs that increase cholinergic transmission can help to reduce effects of Alzheimer’s.
Again no prevention of nerves dying, but helps to overcome deficits.
Which acetylcholinesterase inhibitors (anticholinesterases) can be used in Alzheimer’s?
Donepezil
Rivastigmine
Galantamine
All are reversible acetylcholinesterase inhibitors that are partially selective for the CNS
Galant amine is also a nicotinic agonist.
What side effects are expected with Alzheimer’s drugs which increase acetylcholine?
Increased GI tract movement ie diarrhoea Bradycardia Bronchoconstriction Increased secretions Hypotension Hallucinations Dizziness
Also remember that as this is primarily a disease of the elderly, so other medications/comorbidities is likely, and can cause interaction.
Be very careful of reduced renal or liver function
What is the treatment plan for mild or moderate Alzheimer’s?
Mini mental state examination, specialist decide it is worth using.
Support in place
Unpleasant to use, so only continue if improvement or no decrease. If decrease in cognitive function, do not continue as the anticholinesterases are not producing any benefits.
Normally only a short term improvement 2-6 months.
Compliance is also a problem, intentional and unintentional non compliance
What other types of drugs than anticholinesterase can be used to treat moderate dementia or those who are intolerant to anticholinesterase?
Drugs which target the NMDA receptors. Antagonist, reduces excitotoxicity caused by glutamate at the NMDA receptor.
Memantine
