Degeneration And Dementia Flashcards
Give examples of conditions caused by central degeneration of the nervous system
Alzheimer’s
Multiple Sclerosis
Parkinson’s
Huntingdon’s
Give examples of conditions caused by peripheral degeneration of the nervous system
Diabetic Neuropathy
Motor Neurone Disease
Guillain Barre syndrome
What are the 3 main types of neurodegeneration?
Wallerian
Axonal
Myelin
What is Wallerian neurodegeneration?
Distal degeneration of axon and myelin
Generally trauma induced
What are the 3 classifications of Wallerian neurodegeneration (according to Seddon’s classification)?
Neuropraxia (often stretching with no actual damage to fibres of sheathing)
Axonotmesis (damage to axon but not sheathing)
Neurotmesis (partial or complete severance of axon and sheathing)
What is axonal neurodegeneration?
Loss of axon proximal to cell body
Some regeneration can occur
What is myelin neurodegeneration?
Loss of Schwann cells/ ogliodendrogial cells affecting conduction velocity
What are amyloid plaques?
Aggregations of misfolded/ fragmented proteins
What causes amyloid plaque build up?
Changes in phosphorylation and protein folding leading to increased beta-sheet formation
What type of amyloid plaques are found in Alzheimer’s Disease?
Beta-amyloid
What type of amyloid plaques are found in Parkinson’s Disease?
Alpha-synuclein
What is the normal function of tau?
Structural composition of microtubules for transport in the neuron
What causes neurofibrillary tangles?
- Hyperphosphorylation leads to misfolding
- Misfolding leads to breakdown of tubules and beta-sheet/ fibrils formation
- Fibrils aggregate to form tangles
What are inclusions?
Aggregation of intracellular proteins (including Lewy bodies and Pick cells)
What is diabetic neuropathy?
Axonal degeneration
Can be peripheral, autonomic or central
Presentation is often symmetrical ‘glove and stocking’
Presents with pain, ulcers, tingling or poor balance
What causes diabetic neuropathy?
Mixture or microvascular disease and glycolated end products, activated Protein Kinase C and polyols (secondary to high glucose)
What causes the symptoms of motor neuron disease?
Degeneration of the motor pathways, affecting outflow from the anterior horn cells
Aetiology is unknown
What are the symptoms of MND?
UMN and LMN features
Muscle weakness
Atrophy
Bulbar/ pseudobulbar features
What is Guillain-Barre syndrome?
An autoimmune reaction triggered by preceding viral or bacterial infection.
Demyelinating disorder.
What are the symptoms of Guillain-Barre syndrome?
Rapid onset weakness/ tingling spreading from legs to rest of body Paralysis (in some cases) Autonomic dysfunction Difficulty with bladder/ bowel control Severe pain
How is Guillain-Barre Syndrome treated?
IV immunoglobins
Plasmapheresis (filtering of blood)
What is multiple sclerosis?
A primary inflammatory, autoimmune disease causing CNS demyelination
How can MS be seen on MRI?
‘Plaques’ of products of inflammation accumulate in demyelinated areas are seen as flares in white matter regions of CNS
What is the histology of Parkinson’s Disease?
Loss of dopamine neurons in the Substantia Nigra
Presence of Lewy bodies
Raised alpha-synuclein/ parkin levels
Loss of pigmented cells in Substantia Nigra
Where are Lewy Bodies seen in Dementia with Lewy Bodies?
Neocortex
Basal ganglia
Diencephalon