Spinal cord injury- the consequences Flashcards
What is the ASIA scale ?
american spinal injury association
A to E= A= no sensory and no motor pathways
E= normal
many papers use this scale to qualify patients level of injury
means of looking at the level of the injury
What percentage of SCI are in males?
80%
What is the average age of SCI ?
- 2 years (since 2005)
- it used to be much younger, 20s
What percentage of patients experience complete neurologic recovery by hospital discharge?
less than 1%
What are the major causes of SCI?
majority are due to falls and then its road accidents
What happens immediately after SCI ?
spinal shock
- areflexia (absent reflexes) or hypo-reflexia and flaccid paralysis- completely unable to move
- hypotension
What happens about a week after SCI?
return of segmental reflexes and hyper-reflexia
- some recovery of reflex but sometimes hyperreflexia
- autonomic dysreflexia
What happens months after SCI?
spastic paralysis-large spasms and clonus
What is a cautionary tale after SCI?
bradyarrhythmias following SCI
- they are a cause of circulatory collapse that should be considered following a trauma
- you’d expect a reflex response to be activated to increase BP and also HR
What are other issues that should be considered with SCI ?
- pressure sores= huge concern
- osteoporosis and fractures
- deep vein thrombosis
- loss of body temperature control
- cardiovascular disease
- respiratory complication- removal of secretions - injuries of greater than or equal to C4 may cause problems
What are the stages of pressure sores ?
4 stages- by stage 4 the sore is all the way through to the bone and this can lead to sepsis and then death
Why do SCI patients suffer pain?
it occurs due to reorganisation of the cortex
- patients can suffer neuropathic pain
- measured the activity within the brains of control patients, sic patients with no pain and sci patients with pain and it demonstrated activation of the S1 region but the precise locations of activation varied greatly
What happens within the sc in SCI?
-limited neurogenesis
-inhospitable environment for growth
-poor intrinsic signals
– losing all supra spinal control and afferent inputs to brain (reflex control)
proliferation of astrocytes which is initially meant to be protective for the SC but actually it prevents further sprouting and therefore it is difficult for regeneration to occur
los myelin
What are the major aspects affected in SCI?
neurochemical problems anatomical problems excitotoxcity inflammation physiological problem
this all leads to loss of neurones and oligodendrocytes
What is the link between excitotoxicity and oligodendrocyte death?
oligodendrocytes are critical for myelination in the CNS and therefore their death leads to loss of myelination
Why is there controversy surrounding immune cells?
DEPLETE MACROPHAGES= improve function
- at 28 days there was an increase in hind limb scores but there was no statistical significance
MACROPHAGES CAN PROMOTE RECOVERY
- there was a much higher percentage of recovered rate in the treated group and they had smaller cysts
Why does the extent of autonomic dysfunction vary ?
it is dependent on the level of injury
- autonomic changes after SCI include loss of descending control= lower SBP and DBP
- bladder and bowel control is lost- irregular level of contraction
What is the degree of autonomic dysreflexia correlated with ?
degree of SCI and the loss of serotonergic fibres
- can cause abnormal autonomic effects such as large increases in BP which can be fatal
-
What happens in animal models when the weight of the weight drop to induce the SCI increase?
as the weight of SCI increases the amount of serotonin fibres reduces
e.g. at 20g there is still relatively high levels of serotonin but at 50g there is loss of all serotonin fibres in the raphae pallidus
What is the link between serotonin and autonomic dysreflexia?
although the loss of serotonergic neurones correlates with the autonomic dysreflexia , their loss isn’t necessarily the cause of autonomic dysreflexia
What happens after a 50g clip SCI?
CGRP-IR afferent fibres are increased- sprouting occurs
- reactive growth and potential new synapse formation occurs after SCI
there are also exaggerated responses of SPNs to stimuli after SCI-e.g. response to noxious stimuli causes a larger response
What happens to thermoregulation after SCI?
it is impaired.
data from 1 patient showed that over a 6 month period he suffered recurrent episodes of hypothermia
connections between the brain and SC are lost therefore they cant control temperature as well
What are the highest priorities for paraplegic patients?
to improve
- sexual function
- bladder/bowel/autonomic dyreflexia
- trunk stability
What are the highest priorities for quadraplegic patients?
to improve
- arm/hand function
- sexual function
- trunk stability
What is research generally always looking into?
always aiming to improve motor function which actually isn't one of the highest priorities for SCI patients research 1) motor function 2) then autonomic 3)then sensory
What have the majority of publications in SCI been in?
lower urinary tract then cardiovascular/respiratory function and then sexual function
What are the different forms of SCI?
transections: not that common
hemisections: useful for comparing sides
contusions: applying specific weight drop to break vertebra- specific clips
What stimuli can induce autonomic dysreflexia?
it can occur in response to both noxious and innocuous stimulation
- autonomic dysreflexia in response to noxious stimulation increases over time after SCI compared to that evoked by innocuous stimulation
