Lecture 43: Injuries of the Spinal cord Flashcards
1
Q
Brown-Sequard syndrome?
A
Spinal hemisection causes paralysis and loss of discriminatory sensation on the side of injury and loss of pain and temprature on the opposing side. All from the level of injury down.
2
Q
Acute, complete spinal cord lesion? stage 1?
A
- A period of areflexia (Spinal shock) lasting 1-3 days: due to loss of excitatory inputs from descending tracts.
eg. after complete lesion at Th8
- Paraplegia (flaccid)
- total anaesthesia below T8
- areflexia below T8 -no tenfon reflexes; plantar response silent
- BV dilated in lower part of body (moderate BP drop- much larger in quadraplegics) = role of RVL (rostral ventrolateral medulla)
- sweating absent (odd as the skin will be red)
- bladder and bowel atonic
3
Q
Acute, complete spinal cord lesion? stage 2?
A
- Recovery (partial) and additional symptoms several weeks after injury
- increased muscle tone (but voluntary movements remain absent)
- hyperactive stretch reflexes
- reflex emptying of bladder and rectum
- inc in BP but unstable (autonomic dysreflexia; more pronounced in quadraplegics)
- flexor (withdrawal) reflexes on noxious stimulation recover
- extensor plantar (babinski) reflex -plantar stim > toe dorsiflex
- paresthesias (eg. burning in the abdomen)
4
Q
Acute, complete spinal cord lesion? stage 3?
A
Mechanism of ‘Recovery’?
- sprouting of axon terminals and formation of new synapses
- re-programming of remaining axon connections; synaptic plasticity
- denervation supersensitivity (inc. receptor expression) as some receptors become easier to trigger due to the lack of connections now reaching it.
5
Q
Regeneration of the spinal cord (in experimental animals)?
A
- nerve grafts
- neutralising antibodies to a growth-inhibiting myelin-associated glycoprotein (MAG) and NOGO-A secreted by oligodendrocytes
- trophic factors (eg. NT-3, GDNF)
- bridges with human foetal spinal cord (ethical concerns)
- cell transplant (embryonic stem cells and bone marrow stem cells)
