Dementia & Degeneration Flashcards
Which diseases are characterised by central degeneration?
- Alzheimer’s - Multiple Sclerosis - Parkinson’s - Huntington’s
Which diseases are characterised by peripheral degeneration?
-Diabetic Neuropathy -Motorneuron disease -ALS -Guillain Barre Sydrome
Name 3 types of neurodegeneration
-Wallerian -Axonal -Myelin
Describe Wallerian degeneration
- Distal degeneration of axon and myelin, generally trauma induced. -Rupture - cuts transmission completely
Describe Axonal degeneration
-Dying back of the axon proximal to cell body -Some regeneration is possible -progressive
Describe myelin degeneration
-Loss of oligodendroglial (central)/Schwann (peripheral) cells affecting conduction velocity -Seen in MS (central) -Seen in Guillain Barre (peripheral)
Name 2 causes of Wallerian Degeneration
-Head trauma (shaken baby syndrome, diffuse axonal injury) -Nerve compression
Why is regeneration more likely in the periphery rather than central nervous system?
-Schwann cells in the periphery are better than oligodendroglial cells at releasing growth factors
What are the 3 classifications of Wallerian degeneration?
- Neuropraxia 2. Axonotmesis 3. Neurotmesis
What are amyloid plaques?
-Aggregations of misfolded/fragmented proteins -Caused by changes in phosphorylation or protein folding -Lead to increased Beta sheet formation
What are beta-amyloid plaques associated with?
Alzheimers disease
what are alpha-synuclein associated with
Parkinson’s disease
What are prion proteins associated with?
CJD
What are Tau proteins?
Maintain the structural composition of microtubules, allowing transport through the neuron.
What are neurofibrillary Tangles?
- Hyperphosphorylation of tau proteins leads to misfolding -misfolding causes breakdown of tubules, B-sheet and fibril formation -Fibrils aggregate to form tangles. -This occurs OUTSIDE the cell
What are inclusions?
-Intracellular protein aggregations including LEWY BODIES and PICK CELLS -Generally alpha-synuclein -Inclusions are INTRACELLULAR
How does diabetic neuropathy present and what is it caused by?
Presentation: Pain, ulcers, tingling, poor balance Caused by: microvascular disease, activated PKC, polyols (secondary to high glucose)
How does Motor Neuron Disease (MND) present?
- UMN and LMN features -Bulbar or pseudobulbar features -muscle weakness and atrophy -no sensory signs, bladder involvement or ocular involvement
What is MND caused by?
-Degeneration of the motor pathways, affecting outflow from the anterior horn cells
What is Guillain-Barre Syndrome?
- Autoimmune reaction triggered by preceding viral/bacterial infection -Rapid onset weakness and tingling that spreads through the body. Normally starts in the feet/legs and spreads upwards -Demyelinating disorder -Treated with IV immunoglobulins and plasmapheresis