Neuronal damage Flashcards
List and describe the three types of neuronal damage
Neuronopathy- damage to body
Axonopathy- damage to fibres
Synaptopathy- damage to ending
What is worse, CNS or PNS damage?
CNS
Which part of the neurone is able to repair and which isn’t
bodies - cant NO TREATMENT
nerve endings - can LIMITED TREATMENT
List three ways damage to nerve fibre can occur:
- Damage to Schwann cell- myelinopathy
- Direct damage to axon- axonopathy- due to trauma
- Indirectly via endoneurium- neurovasculopathy
What happens when we damage a nerve?
Proximal- attempted regeneration
Distal- inevitable degeneration- fragmentation
order of neureums in a nerve
epineureum perineureum endoneurium
what is endoneurium
microenvironment continuous with subarachnoid space
what happens if the gap in the nn becomes greater than 10 mm during regrowth
neuroma
and atrophy
due to gap too wide and dense scar tissue
What is the grading of nerve injury?
1- temporary and reversible neuropraxia- conduction interruption to grade 5 Complete nerve transection neurotmesis
Describe the issue of time window
Muscle atrophy happens immediately after denervation, plateus after 4 months
Motor endplates initially increase, no longer functional beyond 12 months
Realistic window of 12-18 months for muscle reinnervation
surgical ways of repairing nn damage
- end to end closure if gap 2cm
- nerve grafting from small cutanous nn
- condutis - synthetic tubes nonneural tissue
Which factors affect outcomes after surgical nerve repair?
- AGE- younger pts hav better results- cortical plasiticity
- Mechanism of injury- sharp cut better than blunt
- Level of injury- more distal, better expected outcome
Why is CNS repair difficult?
Astroglia and oligodendroglia inhibit self repair and regeneration
what is Reactive astrogliosis
Mechanism to minimise and isolate initial damage
Acts as regeneration barrier
Results in irreversible glial scarring- and CSF filled cyst
