Dementia: Neuropathology & Clinical Aspects Flashcards
(36 cards)
Dementia disorders (4)
- Alzheimer’s disease
- Dementia with Lewy bodies
- Frontotemporal dementia
- Vascular dementia
Neuropathology of Dementia
- Microscopically
- Intra neuronal inclusion bodies
- Extra neuronal changes (p…)
- Macroscopically
- Generalised brain …
- Region specific … depending on dementia disorder
- Enlarged …
-
Microscopically
- Intra neuronal inclusion bodies
- Extra neuronal changes (plaques)
-
Macroscopically
- Generalised brain atrophy
- Region specific atrophy depending on dementia disorder
- Enlarged ventricles
Neuropathology of Dementia (2)
- … of proteins
- Abnormal …
- Neuroinflammatory environment
- Damaged neurons, cell …
- Protein involved:
- Amyloid, t…, s…
- Misfolding of proteins
- Abnormal accumulation
-
Neuroinflammatory environment
- Damaged neurons, cell death
-
Protein involved:
- Amyloid, tau, synuclein
Tau abnormalities
- … disease
- … dementia
- Alzheimer’s disease
- Frontotemporal dementia
Tau:
- Normal …
- Highly …
- Mostly found in …
- Mainly present in …
- Function: modulate stability of axonal microtubules, transport
- 6 isoforms -> 352-441 amino acid length (don’t need to know exactly)
- Disease -> … forms
- Leading to paired helical filaments (PHF)
- Neurofibrillary tangles (NFTs)
- PHFs -> NFTs -> Neurodegeneration
- Phosphorylation of tau is regulated by activated kinases
- … of tau can result in self-assembly of tangles of paired helical filaments (PHF)
- Normal protein
- Highly soluble
- Mostly found in brain
- Mainly present in axons
- Function: modulate stability of axonal microtubules, transport
- 6 isoforms -> 352-441 amino acid length (don’t need to know exactly)
- Disease -> hyperphosphorylated forms
- Leading to paired helical filaments (PHF)
- Neurofibrillary tangles (NFTs)
- PHFs -> NFTs -> Neurodegeneration
- Phosphorylation of tau is regulated by activated kinases
- Hyperphosphorylation of tau can result in self-assembly of tangles of paired helical filaments (PHF)
Tau:
- Normal protein
- Highly soluble
- Mostly found in brain
- Mainly present in axons
- Function: modulate stability of axonal microtubules, transport
- 6 isoforms -> 352-441 amino acid length (don’t need to know exactly)
- Disease -> hyperphosphorylated forms
- Leading to … helical filaments (PHF)
- … tangles (NFTs)
- PHFs -> NFTs -> …
- Phosphorylation of tau is regulated by activated …
- Hyperphosphorylation of tau can result in self-assembly of tangles of paired helical filaments (PHF)
- Normal protein
- Highly soluble
- Mostly found in brain
- Mainly present in axons
- Function: modulate stability of axonal microtubules, transport
- 6 isoforms -> 352-441 amino acid length (don’t need to know exactly)
- Disease -> hyperphosphorylated forms
- Leading to paired helical filaments (PHF)
- Neurofibrillary tangles (NFTs)
- PHFs -> NFTs -> Neurodegeneration
- Phosphorylation of tau is regulated by activated kinases
- Hyperphosphorylation of tau can result in self-assembly of tangles of paired helical filaments (PHF)
How can hyperphosphorylation of tau cause neurodegeneration?
results in self-assembly of tangles of paired helical fillaments - leading to neurofibrillary tangles - leading to neurodegeneration
What are Neurofibrillary tangles (NFTs)?
Neurofibrillary tangles (NFTs) are aggregates of hyperphosphorylated tau protein that are most commonly known as a primary biomarker of Alzheimer’s disease.
Neurofibrillary tangles (NFTs) are aggregates of … tau protein that are most commonly known as a primary biomarker of … disease.
Neurofibrillary tangles (NFTs) are aggregates of hyperphosphorylated tau protein that are most commonly known as a primary biomarker of Alzheimer’s disease.
Neurofibrillary tangles (NFTs)
- Described by alois Alzheimer
- Seen in neurons after staining
- Hamatoxylin
- Eosin
- Bielschowsky
- Bodian
- Congo red
- Most commonly found in temporal lobe structures
- …
- …
- Consist of … 10 nanometer diameter filaments twisted around each other in a helical manner (… helical filaments HF)
- Described by alois Alzheimer
- Seen in neurons after staining
- Hamatoxylin
- Eosin
- Bielschowsky
- Bodian
- Congo red
- Most commonly found in temporal lobe structures
- Hippocampus
- Amygdala
- Consist of paired 10 nanometer diameter filaments twisted around each other in a helical manner (paired helical filaments HF)
Amyloid
- Amyloid precursor protein (APP) is a transmembrane glycoprotein
- Broken down and eliminated in … brain
- APP is split by enzymes B-secretase then y-secretase (Gamma)
- B-amyloid is a peptide of 39-43 amino acids
- Most common forms are AB40 and AB42
- … is more common of the two, but … is the more fibrillogenic and is associated with disease states
- Fragments accumulate to form P…
- Build up of B-amyloid … cause neuronal damage
- Amyloid pathology - occurs outside neurons
- Amyloid precursor protein (APP) is a transmembrane glycoprotein
- Broken down and eliminated in normal brain
- APP is split by enzymes B-secretase then y-secretase (Gamma)
- B-amyloid is a peptide of 39-43 amino acids
- Most common forms are AB40 and AB42
- AB40 is more common of the two, but AB42 is the more fibrillogenic and is associated with disease states
- Fragments accumulate to form plaques
- Build up of B-amyloid plaques cause neuronal damage
- Amyloid pathology - occurs outside neurons
Amyloid
- Amyloid precursor protein (APP) is a transmembrane glycoprotein
- Broken down and eliminated in normal brain
- APP is split by enzymes B-secretase then y-secretase (Gamma)
- B-amyloid is a peptide of 39-43 amino acids
- Most common forms are AB40 and AB42
- AB40 is more common of the two, but AB42 is the more fibrillogenic and is associated with disease states
- Fragments accumulate to form plaques
- Build up of B-amyloid plaques cause neuronal damage
- Amyloid pathology - occurs outside neurons
- Amyloid precursor protein (APP) is a transmembrane glycoprotein
- Broken down and eliminated in normal brain
- APP is split by enzymes B-secretase then y-secretase (Gamma)
- B-amyloid is a peptide of 39-43 amino acids
- Most common forms are AB40 and AB42
- AB40 is more common of the two, but AB42 is the more fibrillogenic and is associated with disease states
- Fragments accumulate to form plaques
- Build up of B-amyloid plaques cause neuronal damage
- Amyloid pathology - occurs outside neurons
Amyloid - … is more common of the two, but … is the more fibrillogenic and is associated with disease states
Amyloid - AB40 is more common of the two, but AB42 is the more fibrillogenic and is associated with disease states
Frontotemporal dementia:
- … pathology
- Pick’s disease
- Pick bodies -rounded, microscopic structures found within neurons, aggregates of tau
- Hirano bodies
- Neurons swell, taking on a “ballooned” appearance. Hence called balloon cells
- Plaques and tangles are not found in Pick’s disease
- FTD is present in … and … temporal lobes
- Tau pathology
- Pick’s disease
- Pick bodies -rounded, microscopic structures found within neurons, aggregates of tau
- Hirano bodies
- Neurons swell, taking on a “ballooned” appearance. Hence called balloon cells
- Plaques and tangles are not found in Pick’s disease
- FTD is present in frontal and anterior temporal lobes
Synuclein abnormalities
- … disease
- Dementia with … bodies
- … aggregates of alpha-synuclein protein
- Parkinson’s disease
- Dementia with Lewy bodies
- Fibrillary aggregates of alpha-synuclein protein
Frontotemporal dementia = present in … and … temporal lobes
Frontotemporal dementia = present in frontal and anterior temporal lobes
Dementia with Lewy bodies
- S..
- Small, Presynaptic neuronal proteins comprised of alpha, beta, gamma-synucleins of which only alpha-synuclein aggregates
- Found in neurons and … cells
- Function is lipid vesicle binding, inhibition of phospholipase D2 and protein kinase C, dopamine uptake and as a chaperone have been ascribed to alpha-synuclein
- Proteins of 140 amino acids, that is expressed predominantly in neurons
- Predominantly expressed in neocortex, hippocampus, substantia nigra and cerebellum
- Can … to form intracytoplasmic inclusions in neurons (Lewy bodies)
-
Synuclein
- Small, Presynaptic neuronal proteins comprised of alpha, beta, gamma-synucleins of which only alpha-synuclein aggregates
- Found in neurons and glial cells
- Function is lipid vesicle binding, inhibition of phospholipase D2 and protein kinase C, dopamine uptake and as a chaperone have been ascribed to alpha-synuclein
- Proteins of 140 amino acids, that is expressed predominantly in neurons
- Predominantly expressed in neocortex, hippocampus, substantia nigra and cerebellum
- Can aggregate to form intracytoplasmic inclusions in neurons (Lewy bodies)
Dementia with Lewy bodies
- Lewy body dementia (LBD) is a disease associated with abnormal deposits of a protein called alpha-… in the brain
- Lewy body dementia (LBD) is a disease associated with abnormal deposits of a protein called alpha-synuclein in the brain
Lewy bodies
- Spherical, intranuclear, cytoplasmic eosinophilic inclusions
- Abnormally truncated and phosphorylated neurophilament proteins
- Contain: alpha-…, ubiquitin, associated enzymes
- Spherical, intranuclear, cytoplasmic eosinophilic inclusions
- Abnormally truncated and phosphorylated neurophilament proteins
- Contain: alpha-synuclein, ubiquitin, associated enzymes
Vascular dementia
- Can result from … or … brain damage
- The three most common mechanisms causing disease:
- Single, strategically placed …
- Multiple cortical …
- Subcortical small-vessel disease
- Clinical deficits are determined by the size, location, and type of … damage
- Because of the variety of pathogenic mechanisms involved in vascular dementia, clinical manifestations can be heterogeneous
- Can result from ischaemic or haemorrhagic brain damage
- The three most common mechanisms causing disease:
- Single, strategically placed infarcts
- Multiple cortical infarcts
- Subcortical small-vessel disease
- Clinical deficits are determined by the size, location, and type of cerebral damage
- Because of the variety of pathogenic mechanisms involved in vascular dementia, clinical manifestations can be heterogeneous
Vascular dementia
- Can result from ischaemic or haemorrhagic brain damage
- The three most common mechanisms causing disease:
- Single, strategically placed infarcts
- … cortical infarcts
- Subcortical …-vessel disease
- Clinical deficits are determined by the …, …, and … of cerebral damage
- Because of the variety of pathogenic mechanisms involved in vascular dementia, clinical manifestations can be …
- Can result from ischaemic or haemorrhagic brain damage
- The three most common mechanisms causing disease:
- Single, strategically placed infarcts
- Multiple cortical infarcts
- Subcortical small-vessel disease
- Clinical deficits are determined by the size, location, and type of cerebral damage
- Because of the variety of pathogenic mechanisms involved in vascular dementia, clinical manifestations can be heterogeneous
The clinical dementia syndrome
- Common features among the various dementia disorders
- Symptomatology
- Diagnosis
- Treatment
- But important differences on each of the above
- Common features among the various dementia disorders
- Symptomatology
- Diagnosis
- Treatment
- But important differences on each of the above
Diagnostic guidelines and principles - dementia - National and international diagnostic guidelines
- NICE guidelines:
- … clinics
- … clinics - old age psychiatrists, geriatricians, neurologists
- … approach
- Involve …/…
- NICE guidelines:
- Memory clinics
- Specialist clinics - old age psychiatrists, geriatricians, neurologists
- Multidisciplinary approach
- Involve carer/spouse
Diagnostic steps - DEMENTIA
- …
- Examination
- …/ECG
- Neuropsychological
- …/activities of daily living
- Neuro….
- History
- Examination
- Bloods/ECG
- Neuropsychological
- Behaviour/activities of daily living
- Neuroimaging