Spinal Cord Injury

Question 1

Spinal cord injury

Answer 1

• Damage to the spinal cord that results in loss of function

Question 2

Mechanisms of injury

Answer 2

Hyperflexion: usually hitting top of the head and disrupting posterior elements

Hyperextension: usually hitting chin on the way down (tears anterior ligament, ruptures disc, sliding vertebrae)

Axial load/vertical compression

Excessive rotation

Penetrating injury

Question 3

Complete SCI

Answer 3

The SC is completely severed and therefore is no neural signalling (function below is lost)

Question 4

Incomplete SCI

Answer 4

Spinal cord is compressed but not fully compromised, therefore some functions are sustained

Question 5

ASIA impairment scale (classification)

Answer 5

Complete (A): lack of function in sacral roots
Incomplete (B): sensory preservation, motor loss below including S4-5
Incomplete (C): motor preservation below injury, more than 1/2 muscle groups motor strength < 3
Incomplete (D): motor preservation below injury, at least 50% have motor strength > 3
Normal: all functions present

Question 6

Types of incomplete cord syndromes

Answer 6

• Central cord
• Brown-sequard
• Anterior cord
• Conus medullaris
• Cauda equina

Question 7

Central cord syndrome

Answer 7

• Most common ISCI
• Usually occurs in falls that involve chin hyperextension
• More common in individuals with prior spinal issues (stress, spondylosis)
• Weaker upper extremities, bladder dysfunction and varying sensory loss below injury

Question 8

Brown-Sequard syndrome

Answer 8

• Hemisection of the cord usually from penetrating injury
• Loss of motor on side of injury
• Loss of sensation on opposite side (pain, temp, touch)

Question 9

Anterior cord syndrome

Answer 9

• Usually caused by strong hyperflexion, causing spinal elements to herniate into anterior SC
• Motor dysfunction and sensory deficit below level of injury

Question 10

Conus medullaris syndrome

Answer 10

• Injury to lumbar and sacral cord (usually L1) that results in flaccid paralysis, muscle atrophy and urogenital deficits (not usually paralysis)

Question 11

Cauda equina syndrome

Answer 11

• Injury to lumbar nerve roots (usually fractures)
• Variable loss of motor and urogenital function, areflexia

Question 12

Complete cord injury

Answer 12

Quadriplegia: high level injury (C1-T1) that involves total loss of function below level of injury, including arms

Paraplegia: loss of function below the level of injury (T1 and lower)

Question 13

Pathophysiology

Answer 13

Primary injury: injury from the time of the initial mechanism (direct trauma)

Secondary: injury occurring over hours to days after due to inflammation, vascular changes and intracellular Ca changes
* Microscopic haemorrhaging and oedema cause impaired microcirculation, which is further decreased by NA and histamine released by damaged tissue
* Leads to ischaemia and cell death
* Extent of the damage is unknown for up to a week, but tissue repair occurs over 3-4 weeks (acellular collagen tissue)

Question 14

General symptoms

Answer 14

• Flaccid paralysis
• Loss of spinal reflexes
• Loss of sensation
• Loss of sweating
• Loss of sphincter tone and urogenital dysfunction

Question 15

Complications - vitals

Answer 15

• Cervical and high thoracic injury can affect autonomic control
• Bradycardia occurs often during suctioning, as this triggers vagal activity that is no longer opposed and controlled
• Hypotension and vasodilation (neurogenic shock)
• Loss of temp control

Question 16

Complications - breathing

Answer 16

Entirely dependent on level of injury
* C1-C4: diaphragm paralysis = ventilation
* C5-T6: intercostal paralysis but diaphragm unaffected = resp support
* T6-12: paralysis of abdominal muscles = decreased function

Question 17

Complications - bladder & bowel

Answer 17

• Called neurogenic bladder/bowel
• This function is also impacted by associated factors (opioids, antibiotics, immobility, fluid balance)

Question 18

Neurogenic shock

Answer 18

• Haemodynamic triad of hypotension, bradycardia and peripheral vasodilation due to severe autonomic dysfunction
• Usually only seen in upper injury (above T6) where there is disrupted sympathetic outflow, unopposed vagal tone and decreased vascular resistance
• Basically the sympathetic system cannot vasoconstrict, leading to decreased venous return, hypotension and low cardiac output (+ cannot increase HR anymore which makes this all worse)
• Can be caused by SCI (only above T6), head trauma, CNS depressats, severe pain, hypoglycaemia

Question 19

Neurogenic shock symptoms

Answer 19

• Bradycardia
• Hypotension with decreased MAP
• Decreased SV and CVP
• Early: warm, pink fingers (cool in later stages)
• Low temp
• Change in mental status

Answer 20

• ABCs
• Fluid resus
• Vassopressors
• Pain mx (stop vasovagal syncope which is triggered by pain)
• Atropine (for bradycardia)
• Should also maintain MAP 85-90 and immobilise spine

Question 21

Spinal shock

Answer 21

• Describes the side effects of SCI that arise following injury, which may last days to weeks
• Classic symptoms: flaccid paralysis, absence of sensation and reflexes, loss of autonomic function (hypotension, poor circulation, lack of temp regulation)

Question 22

SCI Assessment

Answer 22

Airway: clearance, intubation, c-spine precautions
Breathing: monitor breathing patterns and gas exchange, SaO2
* Quad cough: get patient to cough while pushing down on their abdomen to help effectiveness
Circulation: determine neurogenic vs hypovolaemic (brady vs tachy), fluids
Resp:
CNS: GCS, motor function, sensory limitations
Renal/urinary: incontinence
Bloods: ABGs may show resp acidosis due to hypoventilation

Question 23

Management

Answer 23

O2, vitals, spinal precautions, quad cough, suctioning, DVT prophylaxis (no anticoags),
Pain: short acting meds and sedatives
Hypothermia: contraversial, intravascular cooling to 33C to slow metabolic rate, free radicals, inflammation
Cervical traction: devices to pull head up to realign cord (restore blood flow and reduce pressure)
Stabilisation: cervical collar
Surgical: can be early (within 72h) or late (after 7 days rest), and type of surgery depends on deficit, location, instablity etc

Question 24

Preventing complications

Answer 24

Respiratory:
* Immobility increased risk of atelectasis, pneumonia and PE, and high injury risks respiratory insufficiency
* Monitoring of rate, pattern of breathing and breath sounds is essential

GI: abdominal assessment and bowel sounds for cholecystitis, constipation, nutritional deficiencies, bleeding, stress ulcers
* use of NGT to decompress
* PPIs, stool softeners, fluids, mobilisation

Skin: regular turning, specialty beds, nutrition, skin care,

All kids with suspected injuries treated as though they have C spine injury = early immobilisation

Question 25

Autonomic dysreflexia

Answer 25

• After resolution of spinal shock, patients with T6 and above injuries can have uncontrolled, massive sympathetic response to noxious stimuli below level of lesion
• Stimuli: full bladder or distended bowel, skin irritation, UTI, penile stimulation, tight clothes
• Sudden increase in BP over 20mmHg + bradycardia
• Can lead to MI, SAH or stroke

Question 26

Autonomic dysreflexia treatment

Answer 26

• Sit upright to produce orthostatic HTN
• Monitor BP every 5 mins + GCS
• Remove/resolve stimuli
• Antihypertensives

Question 27

Methylprednisolone

Answer 27

• IV corticosteroid that reduces inflammation
• Improves neurological outcome after SCI
• Usually receives bolus dose 3-8h post injury then a 24-48h continuous infusion
• Half life:2.5-4h
• SE: weight gain, muscle and bone weakness, joint instability, headaches, itchiness, mood changes, slow healing

Question 28

Pregabalin

Answer 28

• PO anticonvulsant, used to treat neuropathic pain in SCI
• HL: 6.3h
• SE: dizziness, drowsy, constipation, N/D. headache, drymouth