1.1 Spinal Cord Transection Flashcards
a) What characteristic neurological changes occur immediately and in the first three months following
transection of the spinal cord at the fourth thoracic vertebra? (25%)
Sensory
Immediate Changes:
Sensory Complete sensory loss below the
level of injury (and, to a variable
extent, above the level of
transection due to secondary injury;
haemorrhage, oedema, ischaemia
At three months:
Ongoing anaesthesia.
Development of chronic neuropathic and
nociceptive pain
a) What characteristic neurological changes occur immediately and in the first three months following
transection of the spinal cord at the fourth thoracic vertebra? (25%)
Motor
Immediate
Motor
Spinal shock: flaccid paralysis.
Even reflexes are obliterated as
these depend on tonic
descending facilitation.
@ 3/12
Hyper-reflexia with spasticity. Initially,
upregulation of receptors facilitates reflexes,
then new interneurones develop.
a) What characteristic neurological changes occur immediately and in the first three months following
transection of the spinal cord at the fourth thoracic vertebra? (25%)
Autonomic
Autonomic
Neurogenic shock:
loss of sympathetic function
(in injuries at T4 or above,
but also at lower levels if
significant secondary
neurological damage occurs)
with unopposed parasympathetic activity.
Results in
hypotension, bradycardia and sometimes other arrhythmias.
Loss of other autonomic reflexes
(voiding, bowel emptying, coital).
Autonomic dysreflexia
(or sympathetic hyper-reflexia):
abnormal synapse development
in spinal cord distal to lesion results in
non-noxious stimuli causing reflex sympathetic
output below level of lesion,
resulting in lower body and splanchnic vasoconstriction.
The resulting rise in blood pressure activates
baroreceptors, thus causing vasodilatation
above the level of the lesion and bradycardia,
which is insufficient to reduce blood pressure
to normal.
Onset is variable, may take up to a year to develop.
Bowel emptying, voiding and coital reflexes
return, but may not be efficient and so many
patients require catheterisation.
b) What other clinical problems may develop following this type of injury? (40%)
Respiratory
GI
Haem
Infection
Respiratory:
1 Loss of innervation of intercostal muscles results in failure of expansion of
ribcage and, therefore, reduced tidal volumes.
2 Inefficient seesaw breathing: the diaphragm contracts, pushes abdominal
contents down and out due to loss of abdominal wall tone and the chest
wall is sucked in.
3 Breathing worse in the sitting position. Abdominal contents pull down
on the diaphragm, thus expanding expiratory intrathoracic volume, so
reducing volume for expansion in inspiration. A high proportion of minute
ventilation therefore spent on ventilating dead space, resulting in V/Q mismatch and atelectasis.
4 Difficulty clearing secretions: inefficient coughing due to loss of abdominal wall tone.
- GI
Loss control bladder and bowel function
Constipation
- toxic megacolon / overflow diarrhoea - Haem
Increased risk VTE and PE - Infection
Increased risk of LRTI / VAP /
LL infections - U+E - difficulty interpreting creatinine function secondary to loss of muscle mass
- pressure sores / necrosis
b) What other clinical problems may develop following this type of injury? (40%)
Cardiovascular:
Cardiovascular:
1 Neurogenic shock
(may last 24 hours to several weeks):
vasodilatation and bradycardia resulting in hypotension.
Sensitive to position with postural hypotension.
Sensitive to fluid depletion, especially with positive
pressure ventilation.
2 Later, autonomic dysreflexia predisposes to periods of uncontrolled hypertension, risking headache, flushing, nasal congestion, seizures,
retinal haemorrhages, stroke, coma, death.
3 Long-term, patients are at risk
of ischaemic heart disease due to physical inactivity and development of diabetes.
4 Difficulty with intravenous access due to fragile skin, reduced surface blood flow
b) What other clinical problems may develop following this type of injury? (40%)
Endocrine:
Gastrointestinal:
Endocrine:
> > Initial stress response may
result in hyperglycaemia which may
exacerbate secondary neurological injury.
> > Increased risk of developing
diabetes in the longer term.
Gastrointestinal:
> > Reduced gastrointestinal motility:
delayed gastric emptying
(aspiration risk),
paralytic ileus, constipation, pseudo-obstruction.
> > Increased risk of gall stones and their complications.
> > Prone to stress ulceration due
to unopposed vagal activity.
b) What other clinical problems may develop following this type of injury? (40%)
Haematological:
Immune, infection:
Haematological:
» Immobility and thrombogenicity of trauma predispose to thromboembolic disease.
Risk falls after three months
(possibly due to muscle spasm
facilitating the muscle pump of venous return, decreased venous distensibility and femoral artery atrophy).
Immune, infection:
» Risk of nosocomial colonisation
with multi-resistant organisms.
b) What other clinical problems may develop following this type of injury? (40%)
Cutaneomusculoskeletal:
Cutaneomusculoskeletal:
» Contractures resulting from spasticity
cause pain and further reduction in function.
> > Osteoporosis results from loss of limb use**
> > Risk of pressure sores
including in unusual places such as occiput.
b) What other clinical problems may develop following this type of injury? (40%)
Renal and genitourinary:
Renal and genitourinary:
> > Nephrogenic bladder.
Impaired sensory and motor function may lead to
incomplete voiding (predisposing to infection) and uncoordinated voiding
(predisposing to vesico-ureteral reflux and, thus, chronic kidney disease).
Intermittent or long-term catheterisation is usually required.
b) What other clinical problems may develop following this type of injury? (40%)
Metabolic
Psychological
Metabolic:
» Poor temperature regulation:
vasodilatation may predispose to
cooling, whilst lack of ability to sweat below level of injury may cause hyperthermia.
Psychological:
» At risk of depression, suicide, drug addiction.
List the advantages of a regional anaesthetic technique for a cystoscopy in this patient 20%
1 Avoids autonomic dysreflexia.
2 Avoids the need for intubation**
of a patient who may have previously
had a tracheostomy with its
attendant complications, e.g. tracheal stenosis.
3 Avoids deterioration in lung function
associated with general anaesthesia, thus reducing the risk of postoperative respiratory complications.
4 Avoids opioid use*
with associated respiratory depression.
5 Reduces the risk of aspiration*
associated with delayed gastric emptying.
6 Avoidance of unopposed parasympathetic*
response to airway instrumentation
(bradycardia, cardiac arrest).
d) Why and when may suxamethonium be contraindicated in a patient with spinal injury? (15
Upregulation of nicotinic acetylcholine receptors in extrajunctional sites results in massive potassium release with suxamethonium use.
This effect is seen between approximately 72 hours following injury and six months.
