Spinal Cord Injuries Flashcards
What is a spinal cord injury?
damage to any part of the spinal cord or nerves at the end of the spinal canal
what causes the primary injury in SCI?
trauma, compression, and ischaemia
damage to the intramedullary blood vessels can result in haemorrhage. Due to the limited space in the vertebral canal this haemorrhage can begin to compress the cord and surrounding blood vessels. Vasospasm can also occur and cause further compression and ischaemia to grey matter
what are the processes behind secondary injury in SCI?
- energy depletion can begin to occur due to ischaemia, as a result energy dependant processes begin to fail
- release of inflammatory mediators causes oedema and contributes to the limitation of blood flow
- axonal degeneration may commence
describe and/or review the clinical snapshot of spinal cord injury
What is spinal shock?
The transient loos of all reflexive and autonomic function below the level of cord injury
What is the difference between spinal shock and neurogenic shock?
spinal shock is when reflexes are temporarily lost below the level of injury
neurogenic shock is when bradycardia and vasodilation occur resulting in profound hypotension. This is because of the loss of sympathetic innervation below the injury and unnopposed parasympathetic stimualtion affects on the heart. Neurogenic shock only occurs when injury is at T6 or above
Describe the process behind hypotension in a SCI at T6 or above
Hypotension can be caused by loss of sympathetic innervation below the injury and therefore unopposed parasympathetic innervation.
- arterial and venous dilation below the level of injury cause reduced systemic vascular resistance and reduced venous return
- the heart rate is decreased as a result of unopposed sympathic activation causing a further reduction in cardiac output
What level would you expect to see an SCI if breathing is compromised?
Cervical spine injures (in particular C3-C5 - this is where the phrenic nerve originates which is responsible for the innervation of the diaphragm)
Lower level injuries may preserve innervation of the diaphragm but impact that of the intercostal and abdominal muscles, in turn affecting tidal volume and causing hypoventilation
what is piokilothermia?
the inability to maintain core temperature below the injury through shivering, sweating, vasodilation, or vasocontriction
when this occurs the body below the injury moves toward the environmental termperature
what are common genitourinary complications seen in spinal cord injury?
- priaprism (prolonged full or partial erection)
- urinary retention*
- paralytic ileus (motor activity of the bowel is impaired)*
*can be seen from abdominal distension
what is a complete spinal cord injury?
when all sensorimotor function below the level of injury is lost
what is an incomplete spinal cord injury?
when some sensorimotor function remains below the level of injury
what three criteria are commonly used to classify spinal cord injuries?
the verteral level, the degree, and the mechanism affected
explain the arangement of vertebral levels of the spine and roughly what the nerves from each level innervate
cervical 1-8
thoracic 1-12
lumbar 1-5
Sacral 1-5
What funcitons will injuries affecting C5 - C7 affect?
arm movement and strangth as nerves from these areas are responsible for the innervation of the elbow and wrist
what functions will an injury involving C3-C5 impact?
breathing, these nerves are responsible for the innervation of the diaphragm. Damanage to these will require advanced respiratory support
what functions will injuries to the thoracic spine likely impact?
injuries to the thoricic spine will likley impact ones ability to maintain posture and support breathing as intercostal innervation stems from this area
what functions are injuries including the lumbar spine likely to impact?
- hip, knee, and ankle movement
- lower limb strength
- bowel and bladder function
what does ‘degree’ mean in terms of classifying a spinal cord injury?
this is where you would describe the injury as complete ro incomplete based on the sensimotor function below the level of injury
This label can’t really be given until a few weeks after the injury when swelling etc. has reduced
what does ‘mechanism’ refer to in spinal cord injuries?
This is essentially the moevement involved in the injury. Some examples include; felxion, extension, rotation, and compression
describe the mechanisms ‘flexion’ and ‘flexion-extension’
flexion is the movement of moving the head toward the chest, extension is the movement of the chin directly away from the chest. This type of mechanism is common in acceleraiton-decelleration injuries (i.e. in a car)
describe the mechanism ‘rotation’
as the name suggests, hard to describe
common in diving accidents
describe the mechanism ‘compression’
this can result from a primary injury (e.g. someone landing straight on their head) or can be from secondary swelling. It can also be a result of things like ruptured intervertebral disks, tumours compressing the spinal cord, etc.
describe a ‘hyper-extension’ mechanism
extension of the head beyond usual limits. Can often occur as a result of faling and striking the chin
