Spinal Cord Injury Flashcards
How is SCI (spinal cord injury) the same as TBI?
There is a primary and secondary component
What three spinal cord injuries may cause ischemia/infarction?
Compression
Hemorrhage
Traumatic vasospasm
How soon after primary injury does secondary injury occur in SCI?
Within minutes following initial trauma
___________ mechanisms induce cord edema and due to the rigid confines of the vertebral canal, increased pressures within that canal that reaches maximum pressure within ___-___ days - high risk of ischemia
Pathologic mechanisms
4-6 days
What are the 5 pathologic consequences of cord injury?
Induction of nitric oxide synthase
Release of excitotoxic amino acid
Cellular influx of calcium
Oxidative stress
Lipid peroxidation
What causes hypotension that exacerbates secondary SCI?
Hypotension causes hemorrhage or neurogenic shock
What does nitric oxide (NO) modulate?
vascular tone
insulin secretion
airway tone
peristalsis, angiogenesis
neural development
retrograde neurotransmitter
What is the proximate cause of septic shock?
Nitric oxide (NO) which is a free radical with an unpaired electron and may function in autoimmune disease
Disruption of afferent and efferent signals is caused by what type of cord transection? (complete loss of motor and sensory function below the spinal cord injury).
Complete cord transection
A partial cord transection does what to the spinal cord?
Damages only a portion of the spinal cord. Partial or random preservation of motor or sensory function below the spinal cord injury.
What syndromes are classic partial spinal cord disruption?
Central cord syndrome
Anterior cord syndrome
Brown-Sequard syndrome
Cauda-equina syndrome
What is this type of incomplete (partial) spinal cord injury:
Below injury level, motor weakness or paralysis on one side of the body (hemiparaplegia). Loss of sensation on the opposite side (hemianesthesia). Results from penetrating injuries that cause hemisection that affect half the cord.
Brown-Sequard Syndrome
What is this type of incomplete (partial) spinal cord injury:
Below injury level, motor paralysis and loss of pain and temperature sensation. Proprioception (position sense), touch and vibratory sensation preserved. Caused by damage to the anterior portion of the gray and white matter of the spinal cord.
Anterior cord syndrome
What is this type of incomplete (partial) spinal cord injury:
Below injury level, motor function preserved. Loss of sensory function: pressure, stretch, and proprioception (position sense). Caused by damage to the posterior portion of the gray and white matter.
Posterior cord syndrome
What is this type of incomplete (partial) spinal cord injury:
Results from cervical spinal injuries. Greater motor impairment in upper body compared to lower body. Variable sensory loss below the level of injury. Occurs from a lesion in the central portion of the spinal cord.
Central cord syndrome
What is this type of spinal cord injury is this?:
Follows damage to the lumbar nerve roots and conus medullaris. Bowel and bladder are flexia. Loss of motor sensory function
Conus medullaris syndrome
What is this type of spinal cord injury is this?:
Occurs from injury to the lumbosacral nerve roots below the conus medullaris. Areflexia of the bowel, bladder and lower reflexes.
Cauda equina syndrome
What are the main categories of impairment in the ASIA impairment scale?
A (complete)
B (incomplete)
C (incomplete)
D (incomplete)
E (normal)
What category of the ASIA impairment scale is this:
No motor or sensory function is preserved in the sacral segments S4-S5
A (complete)
What category of the ASIA impairment scale is this:
Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5
B (incomplete)
What category of the ASIA impairment scale is this:
Motor function is preserved below the neurological level, and more than a half of key muscles below the neurological level have a muscle grade of <3
C (incomplete)
What category of the ASIA impairment scale is this:
Motor function is preserved below the neurological level and at least a half of key muscles below the neurological level have a muscle grade of >/=3
D (incomplete)
What category of the ASIA impairment scale is this:
Motor and sensory functions are normal
E (Normal)
SCI occurs in ___-___% of all major trauma cases and at least ____% of these patients have the potential to have an unstable spine
Occurs 2-5%
14% unstable spine
___-___% of SCI are associate with a concurrent TBI
20-60%
Vascular injury, pneumothorax, and pulmonary embolism are associated with what type of trauma?
Thoracic trauma
What is the initial management of spinal cord injury?
ABCs
Cervical spine injury should be presumed in all trauma patients until xray proves otherwise
What is this type of shock pathway?
Immediate depolarization of the axonal membranes from the kinetic energy of the injury to the spinal cord ->
Repolarization of nerve fibers - >
Diminished effect of sympathetic pathways ->
loss of vasomotor tone + diminished sympathetic innervation of the heart ->
vasodilation of blood vessels (visceral and lower extremity) ->
pooling of blood leading to hypotension + bradycardia ->
Treatment: fluid resuscitation +/- vasopressors +/- atropine
Neurogenic shock
What type of shock pathway is this?
Immediate depolarization of the axonal membranes from the kinetic energy of the injury to the spinal cord ->
Repolarization of nerve fibers ->
Clinical marker - bulbocavernosus reflux ->
Temporary features of lower motor neuron lesions (flaccidity, paralysis, loss of reflexes) with resolution within 24 hours
prognosis more reliable based on neurologic exams 72 hours to 1 week following trauma
Spinal shock
SCPP (spinal cord perfusion pressure) = ? - ?
SCPP = MAP - CSFP
What is traumatic SCI frequently associated with?
Systemic hypotension
Reduced spinal cord perfusion pressure
May contribute to secondary ischemic neurologic injury, avoid.
True or false:
Spinal cord perfusion pressure is autoregulated over a range of systemic BP in the same fashion as CBF
True
Systemic vasodilation from loss of sympathetic tone occurs in increasing severity with ascending levels of SCI above what level, leading to hypotension
L2
bradycardia complicates the picture with injuries above what level due to compromise of the sympathetic cardiac accelerator fibers?
T6
What is the first step in the treatment of hypotension in the patient with SCI?
Restoration of intravascular volume
What are the concerns of restoring intravascular volume for hypotensive treatment of SCI patients?
Edema
Cardiac failure
Electrolyte abnormalities
coagulopathy
prolonged duration of post-op ICU stay
What is the treatment for higher cord lesions which result in greater sympathectomy, vasodilation, and thus vascular capacitance
Volume
Pure alpha-agonist (phenylephrine)
What is the treatment for higher cord lesions (upper thoracic and cervical spine) with both hypotension and bradycardia?
Dopamine
Norepinephrine (will restore inotropy and chronotropy as well as vascular tone)
Persistent bradycardia may be seen in high cervical lesions from C_-C_. This is treated with what two things?
C1-C5
Treat with anticholinergics and cardiac pacemaker
What is the neurologic disorder that occurs in association with resolution of spinal shock and a return of spinal cord reflexes?
Autonomic hyperreflexia
Patients with CHRONIC spinal cord lesion above the level of T___ may develop autonomic hyperreflexia when stimulated _______ (above/below) the site of the lesion
Patients with CHRONIC spinal cord lesion above the level of T7 may develop autonomic hyperreflexia when stimulated below the site of the lesion.
Autonomic hyperreflexia is characterized by intense ___________ (vasoconstriction/vasodilation) below the lesion and cutaneous (vasoconstriction/vasodilation) above the lesion, hypertension, and bradycardia
Characterized by intense vasoconstriction below the lesion and cutaneous vasodilation above the lesion, hypertension and bradycardia.
Cutaneous or visceral stimulation (such as distention of the urinary bladder or rectum) below the level of the spinal cord transection initiates afferent impulses that are transmitted to the spinal cord at this level. which triggers what condition?
Autonomic hyperreflexia
______________(Bradycardia/tachycardia) occurs secondary to activation of baroreceptor reflexes
Bradycardia occurs secondary to activation of baroreceptor reflexes.
reflex sympathetic activity below the level of the injury in Autonomic hyperreflexia results in intense generalized ___________ (vasoconstriction/vasodilation) and _____________ (Hypotension/hypertension).
reflex sympathetic activity below the level of the injury results in intense generalized vasoconstriction and hypertension.
What percentage of spinal cord transection above the T___ dermatome will exhibit autonomic reflexia during general anesthesia?
Approximately 85% of patients with a spinal cord transection above the T6 dermatome will exhibit this reflex during general anesthesia.
It is difficult to elicit autonomic hyperreflexia in patient with spinal cord transection below the T___ dermatome
T 10
What stimuli from below T6 can cause autonomic dysreflexia?
Restrictive clothing
Pressure areas
full bladder or UTI
Fecal impaction
What are the 3 medication treatment options for autonomic hyperreflexia
Ganglionic blocking drugs (trimethaphan), act as nicotinic antagonist.
Alpha-adrenergic receptor agonists (phentolamine), control hypertensive emergency, reversible. Can lead to reflex tachycardia
Direct acting vasodilators (Nitroprusside/nitroglycerine)
What medication must not be given for autonomic hyperreflexia?
Beta-adrenergic receptor antagonists, leave alpha unopposed. This causes a paradoxical hypertensive response and possible CHF
Beta blockers
If systolic BP remains >150 or persistent symptoms continue for Autonomic Hyperreflexia, what is the pharmacological treatment?
2% nitro paste (except if they took phosphodiesterase inhibitor in last 24-36 hours)
OR Nitro 0.4mg/spray
OR Captopril 25mg sublingual
OR Nifedipine 10mg bite and swallow
What is the initial treatment for autonomic hyperreflexia?
Site patient upright, remove restrictive clothing
Monitor BP/HR every 2-5min
Check and remove noxious stimuli (bladder, bowel, skin, other)
What is the path of an Autonomic Hyperreflexia response?
Stimulus -> Afferent stimulus -> massive sympathetic response -> widespread vasoconstriction -> HTN -> Baroreceptor signal crisis to brain -> X, XI -> heart rate slowed -> descending inhibitory signals blocked at spinal cord injury
What symptoms do you see above the level of injury in autonomic hyperreflexia
(Vasodilation)
Flushed face
Increased BP
Headache
Distended neck veins
Decreased HR
Increased sweating
What symptoms do you see below the level of injury in Autonomic hyperreflexia?
(Vasoconstriction)
Pale
Cool
No Sweating
