Lecture 9: Pathophysiology And Pharmacology Of Dementia Flashcards
(39 cards)
What is Dementia?
- A disorder associated with impairment of memory, speech, comprehension, motor skills, judgement and orientation
- Changes in cognitive function.
- It is a syndrome (group of symptoms)
What is the pathology of dementia characterised by?
- Cell death in areas of the brain
What age group are mainly affected by Dementia?
- Over 65yrs
What are the 3 most common types of dementia?
- Alzheimers
- Lewy Body
- Vascular
What is alzheimers?
- An irreversible progressive disease slowly destroying memory and thinking skills
What are the senile plaques found in the cerebral cortex of Alzheimers patients made of?
- Extracellular: accumulation of insoluble fragments of beta amyloid
- Intracellular: accumulation of hyperphosphorylated Tau strands
What is the structural changes to brain in Alzheimers?
- Ventricular enlargement
- Shrinking of hippocampus, medial temporal lob
- Enlarge of inferior horns of vesicle
- Thinning of gyrus and deepening of sulcus
- Substantia nigra remains well pigmented
What are the differences between Delirium and Dementia?
- Delirium: Sudden, acute confusion, fast, reversible
- Dementia: Slow (mnths/yrs), progressive, steady decline, chronic memory decline
What are risk factors of Dementia?
- Early life: Less education
- Mid life: Hearing loss, depression, brain injury, Physical injury, Diabetes, smoking, HTN
- Later: Social Isolation
What are the main groups of symptoms of Dementia/Alzheimers
- Cognitive
- Behavioural & Psychological
- Physical/Neurological
What are some cognitive symptoms?
- Amnesia
- Disorientation
- Apraxia: Hard to co-ord muscles for speech, actions
- Aphasia: Language disorder, hard to understand
What are some behavioural symptoms of Dementia/Alzheimers?
- Low mood
- Hallucinations
- Apathy
- Anxiety
- Delusions
What are some physical symptoms of Dementia/Alzheimers?
- Falls
- Seizures
- Dysphagia: Difficult to swallow
- Loss of weight/sarcopenia: loss of muscle mass
- Incontinence
What are some meds that help with the cognitive symptoms?
- Cholinesterase Inhibitors
- Memantine
What are some meds that help with behavioural symptoms?
- Antidepressants
- Antipsychotics
- Hypnotics
What is a med that can help with physical/Neurological symptoms?
- Anticonvulsants
What are the 4 different proteins that can misfold, aggregate/ accumulate?
- Tau
- Amyloid B
- A-synuclein
- Huntingtin protein
What are B amyloid plaques?
- Misfold Ab clump to form plaques and accumulate outside neurons (around blood vessels)
What is Tau and what are neurofibillary tangles?
- Tau normally stabilises microtubules in neurons
- When hyperphosphorylated it forms neurofibrillary tangles (helical filaments) and microtubules collapse which disrupt neuron function
What is the precursor to amyloid plaques?
- Amyloid precursor protein (APP)
How does APP cause plaque formation?
- APP sticks through neuron membrane
- Enzymes cut APP into fragments of protein including beta amyloid
- This leads to extracellular deposition of A B peptides forming plaques
- Plaques in hippocampus and cerebral cortex inhibit neuronal activity
Where does the cholinergic neurons originate from?
- Basal forebrain (nucleus basalisis) to cortex
- Pendunculopontine nucleus to thalamus
What roles does ACH play in brain functions?
- Memory
- Cognition: Executive function, planning, reasoning
- Learning
What happens to ACh in Alzheimiers disease?
-Atrophy of nucleus basalis of meynert causes reduced activity of the choline acetyltransferase enzyme (from choline and acetyl COA) resulting in reduced ACH synthesis which causes impaired memory in AD patients
