Spinal Cord Injury Flashcards
Spinal cord injury
- Damage to the spinal cord that results in loss of function
Mechanisms of injury
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
Complete SCI
The SC is completely severed and therefore is no neural signalling (function below is lost)
Incomplete SCI
Spinal cord is compressed but not fully compromised, therefore some functions are sustained
ASIA impairment scale (classification)
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
Types of incomplete cord syndromes
- Central cord
- Brown-sequard
- Anterior cord
- Conus medullaris
- Cauda equina
Central cord syndrome
- 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
Brown-Sequard syndrome
- Hemisection of the cord usually from penetrating injury
- Loss of motor on side of injury
- Loss of sensation on opposite side (pain, temp, touch)
Anterior cord syndrome
- Usually caused by strong hyperflexion, causing spinal elements to herniate into anterior SC
- Motor dysfunction and sensory deficit below level of injury
Conus medullaris syndrome
- Injury to lumbar and sacral cord (usually L1) that results in flaccid paralysis, muscle atrophy and urogenital deficits (not usually paralysis)
Cauda equina syndrome
- Injury to lumbar nerve roots (usually fractures)
- Variable loss of motor and urogenital function, areflexia
Complete cord injury
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)
Pathophysiology
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)
General symptoms
- Flaccid paralysis
- Loss of spinal reflexes
- Loss of sensation
- Loss of sweating
- Loss of sphincter tone and urogenital dysfunction
Complications - vitals
- 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
Complications - breathing
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
Complications - bladder & bowel
- Called neurogenic bladder/bowel
- This function is also impacted by associated factors (opioids, antibiotics, immobility, fluid balance)
Neurogenic shock
- 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
Neurogenic shock symptoms
- Bradycardia
- Hypotension with decreased MAP
- Decreased SV and CVP
- Early: warm, pink fingers (cool in later stages)
- Low temp
- Change in mental status
- 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
Spinal shock
- 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)
SCI Assessment
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
Management
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
Preventing complications
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
