Spinal cord injury Flashcards
What are the two categories of spinal cord injuries?
traumatic (result of external physical impact)
non-traumatic (result of disease, infection, or tumour)
Initial injury
Spinal cord is wrapped in tough layers of dura.
Rarely torn or transected by direct trauma
Compression (bone displacement, interruption of blood supply to cord, tumor)
Penetrating trauma (gunshot wound or stab wounds)
Primary injury (Initial mechanical disruption of axons as a result of stretch or laceration)
Secondary injury (Ongoing, progressive damage that occurs after initial injury (swelling))
Resulting hypoxia reduces oxygen tension below level that meets metabolic needs of spinal cord (needs o2)
Lactate metabolites (anaerobic metabolism)
Increase vasoactive substances (from stress)
- Norepinephrine
- Serotonin
- Dopamine
By ≤24 hours, permanent damage may occur because of edema.
Edema secondary to inflammatory response is harmful because of lack of space for tissue expansion.
Results in compression of cord and extension of edema above and below injury which increases ischemic damage.
What is apoptosis
happens in initial injury
death of cells, after 24 hours development of edema above and below the level of injury results due to ischemic damage and can cause permanent cord damage
may continue for weeks or months after initial injury
identified by petechial hemorrhages are in central grey matter of cord shortly after injury
Extent of neurological damage caused by spinal cord injury results from
primary injury damage.
- Actual physical disruption of axons
secondary damage due to:
1 ischemia
2 hypoxia
3 microhemorrhage
4 edema
Spinal shock
Temporary neurological syndrome
Characterized by:
1 decreased reflexes
2 loss of sensation
3 flaccid paralysis below level of injury
may last days - mos
may masks pts ability to return to normal functioning
Neurogenic shock
Caused by SCI at T5 or above
Loss of vasomotor tone by injury
Characterized by hypotension, hypothermia and loss of sympathetic innervation (important clinical cues)
Characterized by
1. hypotension
2. hypothermia
3. loss of sympathetic innervation
causes…
1 peripheral vasodilation (edema)
2 venous pooling
3 decreased CO
How are spinal cord injuries classified?
Classified by Mechanism of Injury (MOI):
Skeletal level of injury
Neurological level of injury
Completeness or degree of injury
Major MOIs
flexion.
hyperextension.
flexion–rotation. (most unstable b/c ligamented structures of the spine are torn, severe neurologic deficits occur)
extension–rotation.
compression.
Skeletal level of injury
Injury is at the vertebral level, where there is most damage to vertebral bones and ligaments.
Neurological level of injury
Lowest segment of spinal cord with normal sensory and motor function on both sides of the body
Level of injury may be..
- cervical - paralysis of all 4 extremities (tetraplegia) occurs
- thoracic - paraplegia
- lumbar - paraplegia
Why not sacral - spinal cord ends b/w L1/L2
Degree of Injury
Degree of spinal cord involvement may be
Complete cord involvement
- Results in total loss of sensory and motor function below level of injury (equal on both sides)
Incomplete (partial) cord involvement
- Results in mixed loss of voluntary motor activity and sensation and leaves some tracts intact
- More complicated to assess as S+S are different between L and R sides
ASIA impairment Scale
American Spinal Injury Association (ASIA) impairment scale
Commonly used for classifying severity of impairment resulting from spinal cord injury
used for (recording changes in neurologic status, identifying appropriate functional goals for rehab)
Clinical manifestations for spinal cord injury
Generally a direct result of trauma that causes cord compression, ischemia, edema, and possible cord transection
Related to level and degree of injury
Clients with an incomplete lesion may demonstrate a mixture of symptoms.
The higher the injury, the more serious the sequelae.
- Proximity of cervical cord to medulla and brain stem
Movement and functional goals are related to specific location of spinal cord injury.
What are immediate post-injury problems of a spinal cord injury include
1 A – airway, patency
2 B – adequate ventilation, diaphregmatic movement, degree of chest expansion, respirate, o2 level
3 C – adequate circulating blood volume, is peripheral vasodilation occuring
4 D – prevent extension of cord damage by secondary injury, decrease disability
Respiratory system manifestations
Above level of C4
- Presents special problems because of total loss of respiratory muscle function = Mechanical ventilation is required to keep client alive.
Below level of C4
- Diaphragmatic breathing if phrenic nerve is functioning (resulting in hypoventilation)
- Spinal cord edema and hemorrhage can affect function of phrenic nerve and cause respiratory insufficiency.
Cervical and thoracic injuries cause paralysis of:
- abdominal muscles.
- intercostal muscles.
= client cannot cough effectively (leads to atelectasis or pneumonia)
Artificial airway provides direct access for pathogens (ie trach)
Important to reduce infections
Neurogenic pulmonary edema may occur.
Pulmonary edema (increase in pulmonary and alveolar fluid) may occur in response to fluid overload.
Cardiovascular system manifestations
Any cord injury above level T6 greatly reduces the influence of the sympathetic nervous system
bradycardia occurs.
Peripheral vasodilation results in hypotension.
Relative hypovolemia exists due to increased venous capacitance.
Cardiac monitoring is necessary, IV fluids, vasopressors to support BP
What does peripheral vasodilation cause?
1 decreased venous return
2 decreased cardiac output
Urinary system manifestations
Urinary retention is common.
Bladder is atonic and overdistended.
In-dwelling catheter inserted (acute)
- Increased risk of infection
Bladder may become hyper-irritable (post-acute phase)
- Loss of inhibition from brain
- Results in reflex emptying
Indwelling catheter should be removed, and intermittent catheterization should begin as early as possible (once med stable) – maintains bladder decreases risk of infection
Gastrointestinal system manifestations
If cord injury is above T5, primary GI problems are related to hypomotility.
Stress ulcers common
Intra-abdominal bleeding may occur.
Expanding girth may also be noted.
Less voluntary control over bowel results in a neurogenic bowel.
Injury level of T12 or below, or in spinal shock:
- Bowel is areflexic
- Decreased sphincter tone
As reflexes return,
- bowel becomes reflexic.
- sphincter tone is enhanced.
- reflex emptying occurs.
What does decreased GI motor activity contribute to?
1 deceased motor activity paralytic ileus
2 gastric distension
Intra-abdo bleeding indications
Difficult to diagnose
1 continued hypotension despite treatment
2 drop in hemoglobin and hematocrit
Integumentary system manifestations
Consequence of lack of movement is skin breakdown.
Pressure ulcers can occur quickly.
Can lead to major infection or sepsis.
Thermoregulation manifestations
Poikilothermism
Def’n: Adjustment of body temperature to room temperature
Occurs d/t SNS interruption preventing peripheral temperature sensations from reaching hypothalamus
Ability to sweat or shiver is decreased below the level of injury
