Neuronal damage

Question 1

List and describe the three types of neuronal damage

Answer 1

Neuronopathy- damage to body
Axonopathy- damage to fibres
Synaptopathy- damage to ending

Question 2

What is worse, CNS or PNS damage?

Answer 2

CNS

Question 3

Which part of the neurone is able to repair and which isn’t

Answer 3

bodies - cant NO TREATMENT

nerve endings - can LIMITED TREATMENT

Question 4

List three ways damage to nerve fibre can occur:

Answer 4

• Damage to Schwann cell- myelinopathy
• Direct damage to axon- axonopathy- due to trauma
• Indirectly via endoneurium- neurovasculopathy

Question 5

What happens when we damage a nerve?

Answer 5

Proximal- attempted regeneration

Distal- inevitable degeneration- fragmentation

Question 6

order of neureums in a nerve

Answer 6

epineureum perineureum endoneurium

Question 7

what is endoneurium

Answer 7

microenvironment continuous with subarachnoid space

Question 8

what happens if the gap in the nn becomes greater than 10 mm during regrowth

Answer 8

neuroma

and atrophy
due to gap too wide and dense scar tissue

Question 9

What is the grading of nerve injury?

Answer 9

1- temporary and reversible
neuropraxia- conduction interruption
to grade 5
Complete nerve transection
neurotmesis

Question 10

Describe the issue of time window

Answer 10

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

Question 11

surgical ways of repairing nn damage

Answer 11

1. end to end closure if gap 2cm
2. nerve grafting from small cutanous nn
3. condutis - synthetic tubes nonneural tissue

Question 12

Which factors affect outcomes after surgical nerve repair?

Answer 12

1. AGE- younger pts hav better results- cortical plasiticity
2. Mechanism of injury- sharp cut better than blunt
3. Level of injury- more distal, better expected outcome

Question 13

Why is CNS repair difficult?

Answer 13

Astroglia and oligodendroglia inhibit self repair and regeneration

Question 14

what is Reactive astrogliosis

Answer 14

Mechanism to minimise and isolate initial damage
Acts as regeneration barrier
Results in irreversible glial scarring- and CSF filled cyst