Spinal Cord Injury

Question 1

spinal nerves responsible for the upper limbs?

Answer 1

• C5-deltoid
• C6- wrist extensors
• C7- elbow extensors
• C8- long finger flexor
• T1- small hand muscles

Question 2

spinal nerves responsible for the lower limbs?

Answer 2

• L2- Hip flexors
• L3, L4- knee extensors
• L4,L5-S1: knee flexion
• L5- ankle dorsiflexion
• S1- ankle plantar flexion

Question 3

deep tendon cutaneous reflexes?

Answer 3

• triceps C7,C8
• Biceps C5,C6
• Brachioradialis C6, C7
• patellar (knee jerk) L3,L4
• achilles (ankle jerk) S1, S2

Question 4

What are the two types of injuries to the spinal cord?

Answer 4

• Non-hemorrhagic with only high signal on MRI due to edema
• Hemorrhagic with areas of low intensity within the area of edema

Question 5

what is a primary mechanism of SCI? examples?

Answer 5

immediate effect of trauma to force and direction

• initial crush, shear, impingement, penetration, transection or hemisection, compression, contusion

Question 6

what is a secondary mechanism of SCI?

Answer 6

Neuro deterioration over minutes to hours; due to ischemia or hypoxia

• vascular insufficiency (hypotension, neurogenic shock)
• inflammation/edema (compresison injury, pinches off bloodflow–>ischemia)
• disturbance in ion homeostasis
• cytotoxicity (excessive glutamate release and neuronal excitotoxicity)
• free radical toxicity
• apoptosis
• necrosis

Question 7

SCI pathophysiology?

Answer 7

• most of the damge to the spinal cord is due to the secondary injury that takes place in the minutes and hours following injury and leads to demyelination
• immediate injury causes small microhemorrhages that enlarge (particularly in gray matter)
• may be reversible within 4-6 hours- infarction of white matter
• within 8 hours- global infarction of gray matter at the level of injury- irreversible

Question 8

• 1st priority
• acute respiratory failure is leading cause of death in high cervical injuries
• decision to intubate
• high concentration of O2 may prevent bradycardia or asystole with neurogenic shock
• if bradycardic, atropine or pace
• hypoxia- adverse effect on neuro outcome

Answer 8

airway

Question 9

• lesions above C5 level will cause partial to complete diaphragmatic paralysis
• any lesion above T12 may cause airway compromise
• lesions at c5 and below will allow full diaphragmatic movement, but intercostal muscles and abdominal muscles are affected

Answer 9

breathing

Question 10

• pts. become pikliothermic (body temp changes with temp of environment
• loss of ability to regulate core temp through vasodilation and vasoconstriction
• pt. can become dangerously hyperthermic or hypothermic

Answer 10

exposure

Question 11

• given within 8 hours of injury- some recoverable function
• may inhibit some specific levels of the inflammatory cascade- e.g, decreased edema, prevent K+ depletion

Answer 11

solumedrol

steroid protocol should initiated within 8 hours

Question 12

• transient loss of all neuroloigical function (motor, sensory and autonmic) below the injury level
• flaccid paralysis followed by spastic paresis
• loss of reflexes below SCI, but later recover
• concssion of the spinal cord
• occurs immediately-lasts several days/weeks
• physiologic response; d/t potassium loss from damaged cells
• bowel & bladder involved; priapism

Answer 12

spinal shock

Question 13

• high cervical and thoracic cord (above T6) injury can result in this
• disruption of sympathetic outflow from T1-L2
• typically seen 4-6 hrs after injury with cord lesions above T6
• can last 48hrs- several days
• pathophys: loss of sympathetic outflow with unopposed vagal activity- loss of vasomotor tone (peripheral pooling of blood and decreased preload)
  -hypotension
  -bradycardia (loss of sympathetic tone): tx: atropine
  -hypothermia d/t loss of thermoregulation

tx: fluid resuscitation and vasopressors; cautious to avoid overload

Answer 13

Neurogenic shock

Question 14

• life-threatening: usually with lesions above T6, and occurs as a later complication, but can happen acutely
• SBP rises above 250mmHg, tachycardia, urticaria, flushing, diaphoresis, reflex bradycardia, throbbing HA
• can lead to seizures or stroke
• find the treat the problem
• nociceptive input below injury level usually d/t visceral distension (bladder distention, UTI, fecal impaction, skin lesions)

Answer 14

Autonomic hyperreflexia (medical emergency)

Question 15

ASIA impairment scale

Answer 15

• A= complete: no motor or sensory function is preserved in the sacral segments S4-S5
• B= Incomplete: sensory, but not motor, fxn is preserved below the neurological level and includes sacral segmens S4-S5 (sacral sparing)
• C= incomplete: motor fxn is preserved below the neurlogical level and more than half of key muscles below the neurological level have a muscle grade less than 3
• D= incomplete: motor fxn is preserved below the neurolgoical level and at least half of key muscles below the neurological level have muscle grade 3 or more
• E: normal: motor and sensory function are normal

Question 16

• damage to cord that is not absolute
• can be extremely variable in each individual
• takes 6-8 weeks to see the extent of injury (after shock, swelling, and fluid masses subside)
• some motor and sensory function remain-mixed loss

Answer 16

Incomplete SCI

Question 17

• Complete and irreversible loss of motor/sensory function below level of injury
• paralysis
• persistance beyone 24 hrs- no distal function recovery
• injuries above C5 level cause tetraplegia
• injuries at T1 and below cause paraplegia
• high cervical cord injury (C1, C2, C3) require respiratory mechanical support

Answer 17

complete SCI

Question 18

• direct trauma to anterior spinal cord (hyperflexion, flexion, rotation injury) or anterior spinal artery infarct creating ischemia
• retropulsed disc or bone
• compression fracture
• impairment with pain and temperature below level of lesion (spinothalamic tracts); variable loss of motor function (corticospinal tracts)- can be para- or tetraplegic
• only 10-20% recover motor function

Answer 18

anterior cord syndrome

Question 19

• usually involves cervical region; hyperextension with osteophytic spurs
• weakness w/hand dexterity
• neuropathic pain in hands (UE)
• loss of function in arms- legs usually preserved (deficit: arms > legs)
• myelopathic symptoms
• often occurs in elderly pts with cervical spondylosis and spinal stenosis; surgical decompression
• occurs in young due to sporting events (w/ or w/o fracture or dislocation

Answer 19

central cord syndrome

Question 20

• hyperextension injuries (fractures of posterior elements) or posterior spinal artery infarct
• involvement of dorsal column pathways
• difficulty in coordinated movement of limbs (ataxic gait) proprioception & vibration, but overall strenth and sense of pain preserved

Answer 20

posterior cord syndrome

Question 21

• MOI- penetrating injury
• hemisection of cord (e.g, knife wound, GSW)
• ipsilateral hemiplegia
• ipsilateral loss of fine touch, proprioception vibration (dorsal columns)
• contralateral absent pain (pinprick) and temperature (lateral spinothalamic tract)
• 90% regian bowel and bladder function and ambulatory capacity

Answer 21

Brown-Sequard syndrome

Question 22

Compression of Conus Medullaris/Equina

• due to bony compression or disc protrusions in lumbar or sacral region
• back pain
• bowel/bladder sphincter disturbance
• saddle anesthesia (anus, perineum, buttocks)
• significant LE motor weakness (bilateral)
• LE sensory loss (bilateral)
• absence of achilles reflex
• cauda equina is a nerve root deficit (LMN)
• surgical decompression with 48hrs
• CE prognosis > CM progronsis

Answer 22

Incomplete SCI