Spinal Cord Injury

spinal cord

- major part of the CNS

- from the brainstem to lower back; ends at L2

- protected by vertebrae

-segmental spinal nerves --> sensory + motor function

spinal nerves

- spinal cord segments contain cell bodies & sensory + motor nerve fibers (______ _____)

- innervate specific region of neck, trunk, or limbs

(ie. c3-c5 segment contains phrenic nerve)

- part of PNS; enables connections between CNS (spinal cord segment) + PNS (____ ____ )

dermatome

- area of skin innervated by the sensory fibres of a spinal nerve (PNS)

- indicate the general pattern of somatic sensory innervation by spinal segments

myotome

- a muscle group innervated by the primary motor neurons of a spinal nerve (PNS)

Peripheral Nervous System

- Cranial nerves

- Spinal nerves

- Autonomic Nervous System

ANS

- involuntary functions of cv, smooth/involuntary muscle, glands

- PNS

- SNS

PNS

ANS:

- “Rest + digest” response

- Main NT → Acetylcholine

- cell bodies located in brainstem + S2-S4

- SCI does not alter function (unless brain injury + extension of cervical injury) = functioning PNS

SNS

ANS:

- “Fight or Flight” response

- Main NT → NE

- Cell bodies located from T1-L2

- dysfunction in cervical/thoracic injuries

SNS, PNS

- If ______ dysfunction (cervical/thoracic) = ++++ _______ stim w/o compensation

- manifested in sx + complications

PNS stim

- Pupil constriction

- Bradycardia + vasodilation

- Bronchoconstriction

- Increases GI motility + relaxation of GI sphincter → - stimulates elimination

- Increases gastric secretions → Saliva + HCL production

- Bladder contraction + relaxation of urinary sphincter → stimulates urination

SNS

- Pupil dilation

- Tachycardia + vasoconstriction

- Bronchodilation

- Decreases GI motility + contracts GI sphincter

- Decreases gastric secretions → Saliva + HCL production

- Bladder relaxation + contraction of urinary sphincter

spinal cord injuries (SCI)

- have a devastating effect on health and well-being​

- many injured pt remain independent

- 60-70 yrs age, male 2:1 female

- highest level of injury may require full care

- divided into traumatic and non-traumatic categories​

traumatic, non-traumatic

spinal cord injuries:

- _______ result of external physical impact

- _______ result of disease, infection, or tumour

Traumatic SCI

- younger; 20–30 yrs

- male 4:1 female

- cervical spine most common

- 50% r/t vehicle collisions​; 30-40% falls or work r/t

initial injury (SCI)

Mechanisms:

- Cord Compression

- Penetrating Trauma

cord compression

Initial injury by _______ _______ from:

- Bone displacement (ie. blunt trauma)

- Tumor

- Abscess

- Interruption of blood supply ​​

penetrating trauma

Initial SCI by: ________ _______

- gunshot wound

- stab wound

...

- cord wrapped in tough layers of dura; rarely torn or transected by direct trauma​

- penetrating trauma = tearing and transection

primary injury

SCI​

- initial mechanical injury w/ failure of spinal column (fracture or dislocation)

- imparts force to spinal cord, disrupts axons, blood vessels, and cell membranes

- initial disruption of axons as a result of stretch or laceration

secondary injury

- Ongoing, progressive damage; occurs after initial injury​

- involves vascular dysfunction, edema, ischemia, lyte shifts, inflammation, free radical accumulation + apoptotsis

secondary injury

- cell death (apoptosis) occurs + may continue for weeks-months after initial injury

- may result in permanent cord damage >24HR d/t autodestruction

petechial hemorrhage, cord ischemia

Secondary Injury: Autodestruction

- ________ _______ --> vascular disruption + hemorrhage in surrounding matter = ______ ______

- cord ischemia -> _______ (within 24 hrs) develops & extends above/below SCI = permanent cord damage

hypoxia, lactate metabolites, vasoactive substances

Secondary Injury: Autodestruction

- d/t edema + cord ischemia ________ results --> release of lactate metabolites + vasoactive substances

- _______ _____ byproduct of anaerobic metabolism --> acidosis + increases O2 demand

- ________ _______ (NE, serotonin, dopamin) --> vasopasms + further hypoxia = necrosis (limited ability to adapt to vasospasm)

....

Events Leading to Spinal Cord Ischemia and Hypoxia of Second Injury

extent of neuro damage

______ of _______ ________ from SCI is r/t:

- primary injury damage

- secondary injury damage

primary injury damage

Extent of neuro damage from SCI is r/t:

- Actual physical disruption of axons​

secondary damage

Extent of neuro damage from SCI is r/t:

- r/t cord ischemia, hypoxia, microhemorrhage, edema

- can cause extension of SCI + permanent damage (<24HR)

- prognosis determined at 72HR or longer d/t process of _____ ____ occurring overtime

minimize/manage secondary injury

- Rapid Assessment, Intervention, Immobilization

- first 8 hrs after injury

- limit further destruction

Classified

SCI _______ by:

- Mechanism of Injury​

- Skeletal level of injury​

- Neurologic level of injury​

- Completeness or degree of injury

mechanism of injury

- understanding ________ _ _________ is important +++

- why + how injury occured --> factors contributing to injury + mediate factors for further prevention

- also dictates sx + further investigations + goals of care + progression of injury + risk of complications + management

mechanisms of injury

Major __________ __ _______: ​

- flexion.​

- hyperextension.​

- flexion–rotation.​

- extension–rotation.​

- compression.

flexion injury

Major Mechanisms of SCI:

- _____ _______ of the cervical spine ruptures the posterior ligaments

Hyperextension injury

Major Mechanisms of SCI:

- _________ _________ of the cervical spine ruptures the anterior ligaments

flexion-rotation injury

Major Mechanisms of SCI:

- most unstable of all injuries

- ligamentous structures that stabilize spine are torn

- injury most often implicated in severe neuro deficits

extension rotation injury

- The spine is bent backward + rotated/twisted beyond normal ROM

- ligamentous structures that stabilize spine are torn

compression injury

Major Mechanisms of SCI:

- crush the vertebrae and force bony fragments into the spinal canal

level of injury

May be:

- cervical (C1-C8)

- thoracic (T1-T12)

- lumbar (L1-L2)

Skeletal level

Level of injury

- Injury at vertebral level

- where there is most damage to vertebral bones and ligaments

neurological level

SCI classifications: Level of injury

- the lowest segment of spinal cord with normal sensory and motor function bilaterally

cervical, tetraplegia, quadriplegia

- occurs if the _______ cord is involved

- ​Paralysis of all four extremities (_______ or ________)

C3-C5 injuries

- impact phrenic nerve

- can result in phrenic nerve damage = diaphargm paralysis

- major impact on breathing

- may need mechanical ventilation, relearn how to breath

C5-t1 injuries

- damage brachial plexus (shoulder, arm, and hand nerves)

- result in paralysis of upper limbs

medulla

consider proximity of cervical spinal cord to _________

- vital centres that control Ventilation, HR, ​Vasomotor function

thoracic/lumbar, paraplegia

- results if _______/______ cord is damaged.

- paralysis of lower limbs (below T1)

T1 to L4 injuries, T5

- Loss SNS innervation

- Loss Temp control (poikilothermia)

- Loss of Vasomotor tone

risk of neurogenic shock above _______

T12

- paralysis of intercostal + abdominal muscles

- affect bowel, bladder, and trunk control

...

- sx depend on the degree of paralysis

- potential for rehab depends on the level of injury

spinal cord involvement

Degree of _______ _____ ______ may be:

- complete or incomplete

complete

Degree of spinal cord involvement:

- Results in total loss of sensory and motor function below level of lesion (injury)​

- transection of spinal cord + absolute paralysis below injury

- 6 types

complete

SCI w/ ________ involvement:

- central cord syndrome

- anterior chord scent syndrome

- brown saccard syndrome

- posterior chord syndrome

- cada achina syndrome

- conus medullaris syndrome

incomplete (partial)

Degree of spinal cord involvement:

- Results in mixed loss of voluntary motor activity and sensation and leaves some tracts intact ​

- higher capacity to regain more function

American Spinal Injury Association (ASIA) impairment scale​

- used for classifying severity of impairment resulting from spinal cord injury​

- very comprehensive; assess motor, sensory function + determine neuro level + completeness of injury

- used to record changes in neuro status + identifying goals for rehab

SCI manifestations

- a direct result of trauma that causes cord compression, ischemia, edema, and possible cord transection​

- r/t level and degree of injury​

- incomplete lesion = mixture of symptoms​

higher

- ________ the injury = more serious the sequelae​​

​- rehab goals r/t specific location of SCI

SCI manifestations

- Systemic: Neurogenic Shock

- Neuro: Paralysis, Sensory/Motor dysfunction, Spinal Shock

- Resp: r/t resp muscle functon, WOB

- CV: r/t SNS innervation, DVT

- Urinary: r/t SNS

- GI: r/t SNS

- Integ: skin breakdown/pressure ulcers

- Metabolic: temp reg, pH changes, increased demand

Neurogenic shock

- SCI above T5

- loss of vasomotor tone --> hemodynamic syndrome (massive vasodilation w/o compensation)

- acute condition --> may become irreversible & lead to death

neurogenic shock sx

- hypotension

- hypothermia

- loss of SNS innervation

w/o compensation

loss of SNS innervation

- peripheral vasodilation

- venous pooling + edema

- pulmonary edema

- decreased cardiac output + hypotension

- acute condition --> may become irreversible & lead to death

neuro

SCI Manifestations:

- paralysis r/t level of injury

- motor + sensory function below level of injury

- spinal shock

spinal shock

- temporary loss or reduction of reflexes below injury level; may mask permanent deficits

- occurs immediately following SCI; 50% of pts; lasts days to months

- hard to identify until sx reverse; return of reflexes complicates rehab

- complication: autonomic dysreflexia

return of reflexes

- Client or family may see this as return of function

- may complicate rehab

- hyperactive, exaggerated responses

- penile erections

- spasms

spasm control

- antispasmodic (ie. baclofen)

- botulin toxin for severe cases

Autonomic Dysreflexia

- serious complication of SCI above T6

- develops when reflexes return in spinal shock

- precipitated by bladder/GI contraction, skin or pain stim

- uncompensated CV rxn by SNS --> can cause seizures, stroke, MI, death

Autonomic Dysreflexia sx

- HTN (>300mgHg)

- Bradycardia (pulse <60 bpm)​

- Pounding headache​

- Flushing, Diaphoresis, Dilated pupils, Nausea​

- Piloerection​​​

- Nasal stuffiness​​

resp

SCI Manifestations:

- closely correspond to level of injury; may require ventilation

- cervical injury (above/below C4)

- thoracic injuries

- complications

above C4

SCI Manifestations: Resp

- total loss of resp muscle function; paralysis

- Laboured Breathing, Exhaustion, ABGs Deteriorate

- mechanical ventilation required to keep pt alive (ETT, TRACH) (risk of infection)

cervical injury (below C4)

SCI Manifestations: Resp Complications

- spares diaphragmatic breathing if phrenic nerve functioning (C3-C5)

- but edema + hemorrhage r/t secondary injury can affect phrenic nerve = resp insufficiency

thoracic injuries

SCI Manifestations: Resp Complications

- paralysis of abdominal + intercostal muscles --> hypoventilation

- cannot cough --> atelectasis or pneumonia​

- Trach + NG enteral feeds (loss of gag reflex)

pulmonary edema

Resp Complications:

- increase in pulmonary interstitial + alveolar fluid

- may occur secondary to neurogenic shock or fluid overload in resus

T6, CV

SCI Manifestations:

- SCI above _____ --> reduces SNS innervation

- monitoring necessary

- bradycardia

- peripheral vasodilation + hypotension

- hypovolemia

bradycardia

- d/t PNS stimulation w/o SNS compensation

- +++ PNS stim = cardiac arrest (ie. suctioning or turning pt)

- Tx: atropine

atropine

- may need to be given to treat bradycardia (low HR) to increase HR + prevent hypoxemia

peripheral vasodilation, hypotension, hypovolemia

SCI Manifestations:

- _________ ________ causes decreased venous return --> decreased cardiac output + increased capacity in veins = _________ + ___________

- IV fluids + vasopressors**

DVT, PE

- _______ = common problem

- _______ = leading cause of death

- more difficult to detect --> does not exhibit usual signs such as pain+ tenderness

- assess: doppler, lower limbs, thigh girth, calf pain on dorsiflexion

GU

SCI Manifestations:

- urinary retention (acute phase) --> reflex emptying

- neurogenic bladder (areflexic, hyper-reflexic, dyssynergic)

urinary retention

SCI Manifestations:

- acute phase of SCI or spinal shock

- loss of bladder tone + reflexes for bladder emptying = _____ ______

- can cause overdistension of bladder = urine reflux into kidney --> eventual renal failure

indwelling cath

- inserted in acute phase of SCI

- remove as early as possible, once stabilized, to maintain bladder tone + decrease risk of infection

- move onto intermittent cath

reflex emptying (involuntary)

SCI Manifestations:

- after acute phase; remove cath

- bladder may become hyper-irritable

- d/t loss of inhibition from brain

neurogenic bladder

- when reflexes return in spinal shock; depending on completeness of SCI

- any type of bladder dysfunction r/t abnormal or absent bladder innervation ​

- May be areflexic, hyper-reflexic, dyssynergic

- Diagnose + manage dysfunction, promote bladder emptying

areflexive/flaccid bladder

Neurogenic Bladder:

- no reflex detrusor contractions

- bladder cannot empty --> distension + reflux into kidney

hyperreflexive/spastic bladder

Neurogenic Bladder:

- hyperactive reflex detrusor contractions

- bladder muscle (detrusor) contracts involuntarily during filling --> sudden urge to urinate, frequency, urgency, and urge incontinence

dyssynergic bladder

Neurogenic Bladder:

- lack coordination between detrusor contraction and urethral relaxation

- bladder muscle (detrusor) contracts + urethral sphincter muscle constricts instead of relaxing

- blocks urine outflow = high bladder pressure + potential kidney damage via reflux

GI

SCI Manifestations:

- injury above T5

- stress ulcers

- intra-abdominal bleeding

- neurogenic bowel

t5, paralytic ileus, gastric distension

SCI Manifestations:

- above ______ --> r/t decreased GI motility (SNS)

- contributes to ________ _______ + ______ _______

- TX: NG (distension) + metoclopramide

Metoclopramide

- may be used to treat delayed gastric emptying; increases gastric motility

- dopamine-receptor antagonist

stress ulcers

SCI Manifestations:

- d/t increased gastric secretion (SNS stim)

- peak 6-14 days

- high dose corticosteroids = increase risk

- Prevent: H2R blockers or PPIs

intra-abdominal bleeding

SCI Manifestations:

- difficult to diagnose (may not have pain; absence of sensory/motor function) ​

- *continued hypotension despite treatment

- *drop in Hgb + Hct

neurogenic bowel, t12, spinal shock

SCI Manifestations:

- d/t decreased voluntary control over bowel

- AReflexive/Reflexive bowel

- occurs in injury above _____ or _____ ______

areflexic/flaccid bowel

SCI Manifestations: Neurogenic bowel

- below T12 or in spinal shock

- decreased sphincter tone ---> inability to empty the bowel effectively without manual help

- log roll + MRP does DRE --> assess rectal tone after SCI to determine level of injury

reflexic/spastic bowel

SCI Manifestations: Neurogenic bowel​

- d/t return of reflexes in spinal shock

- sphincter tone is enhanced.​

- reflex emptying occurs; involuntary bowel movements when rectum is full​

pressure ulcer/skin breakdown

SCI Manifestations: Integ

- result of lack of movement + loss of sensory function

- occur quickly as pts cannot sense to move or move independently

- can cause major infection or sepsis

- pt require alternating pressure mattresses

metabolic

SCI Manifestations:

- poikilothermia

- risk of acidosis/alkalosis

- monitor lytes (hypokalemia)

- wt loss & +++ nutritional needs

poikilothermia

SCI Manifestations: metabolic

- body temp adjusts to room temp; does not thermoregulate

- based on level of injury --> sweat or shiver function decreased below injury level

- SNS interruption --> prevents peripheral temp senses from reaching hypothalamus​

metabolic alkalosis, lytes

SCI Manifestations:

- NG suctioning may lead to _______ ________ (d/t removal of K+ in secretions)

- monitor ________ until NG d/c + normal diet resumed

acidosis

SCI Manifestations:

- Reduced tissue perfusion may lead to _________ d/t accumulation of H+ ions and lactic metabolites (byproduct of anaerobic metabolism)

wt loss, nutrient, protein

SCI Manifestations:

- _______ _______ common; pt muscle atrophy quickly

- ________ needs greater than expected

- high ________ diet --> prevent skin breakdown + reduce muscle atrophy

DVT, PE

SCI Manifestations:

- common problem

- assess: doppler, lower limbs, thigh girth, calf pain on dorsiflexion

- _______ ________ = leading cause of death

SCI diagnostics

- CT

- MRI

- vertebral angiography

- Comprehensive Neuro Exam

CT

SCI diagnostics:

- may be used to assess stability of injury, location, and degree of bone injury

MRI

SCI diagnostics:

- gold standard for imaging neurological tissues