SCI Pathology and Intro Flashcards
spinal cord injuries (SCI) can be classified as _____ or ______
traumatic and non-traumatic
or
complete and incomplete
what is traumatic SCI?
- MVA, GSW, jumps and falls, diving
- MOI
- flexion (most common lumbar injury)
- flexion-rotation (most common cervical)
- compression
- penetration
- hyperextension (exclusively cervical)
- pathophysiology of injury types
- transection
- compression
- infection
- degenerative disease
spinal areas of greatest frequency of injury from traumatic SCI
- C5
- C7
- T12
- L1
what are some causes of non-traumatic SCI
- disc prolapse
- vascular insult
- infections
why are thoracic traumatic SCI less common than cervical?
rib cage and higher stability in the T/S compared to C/S
(if injured, T12-L1 is most common site of injury)
common MOI → flexion motion w/vertical compression
describe a typical traumatic lumbar injury
- Neurological damage from trauma is usually incomplete due to large vertebral canal and relatively good vascular supply
- most injuries occur at L1
- Most common MOI → flexion injury
briefly describe the demographics of SCI
- Demographics
- average age at injury → 43
- Males 78% of cases
- highest risk → males 20-29 yrs and 70+ yrs
most common site of injury in SCI
- Cervical (C4 and C5) and thoracolumbar junctions (T11 and T12)
- most mobile part of the spine
- more than half are cervical injuries, a third are thoracic and rest are lumbar
most frequent SCI
incomplete tetraplegia
T/F: the frequency of complete vs incomplete paraplegia is about equal
TRUE
what is the difference between tetraplegia and paraplegia?
- Tetraplegia
- injury to C/S cord (C1-C8)
- involvement of all 4 extremities and trunk
- Paraplegia
- injury to T/S or L/S regions of SC (T1-L5)
- involves BLEs and trunk
describe a complete SCI
- absence of sensory and motor function below lesion level
- more severe presentation of SCI
- Can have zones of partial preservation (ZPP)
- dermatomes and myotomes caudal to the sensory and motor levels that remain partially innervated
describe an incomplete SCI
- involves partial preservation of sensory and motor function below the lesion level
- better prognosis than complete SCI due to preserved axon function
- incomplete SCI occur more frequently than complete
how is the degree SCI (complete vs incomplete level of neuro injury) determined?
ASIA exam
how are SCIs acutely managed?
- primary goal → stabilize spine
- surgery
- external support devices
- Methylprednisone
- small window of opportunity: 3-8 hrs post injury
- stabilize cell membranes
- decrease inflammation
- increase nerve cell impulse generation
- improves blood flow to damaged area
- small window of opportunity: 3-8 hrs post injury
how does methylprednisone impact complete vs incomplete SCI?
- complete
- increases chances for return of function of the last preserved spinal level post SCI
- incomplete
- enhances return of some function below spinal level
list several pathological secondary sequelae of SCI
- Ischemia
- Edema
- Demyelination and necrosis of axons progressing to scar tissue formation
List some complications to SCI
- Spinal shock
- Autonomic Dysfunction
- Pressure Ulcers
- Postrual Hypotension
- Pain
- Spasticity
- Contractures
- Hetertrophic Ossification (HO)
- Edema
- DVT
- Osteoporosis and renal calculi
- Respiratory Compromise
- Bladder and bowel dysfunction
- Sexual dysfunction
what is spinal shock?
a temporary phenomenon with injuries T6 and above
- the cord in its entirety ceases to function below the lesion
- spinal reflexes, voluntary motor control, sensory function, and autonomic control are absent below the level of the lesion
- initially rapid dramatic increase in BP
- followed by steep decline in BP, HR, hypothermia, venous stasis
how long does spinal shock last?
usually 24 hours to several days post injury
1st thing to return is typically sacral/anal reflexes
why does spinal shock occur?
all sympathetic output occurs below T6 so its thought that an injury to this region wipes out communication between the SNS and CNS
ultimately resulting in a loss of sympathetic tone which presents like a LMN injury (even though its an UMN)
what is autonomic dysreflexia?
over-activity of the autonomic nervous system (due to loss of CNS control)
what is the cause of autonomic dysreflexia?
irritating stimulus introduced to body below level of SCI
- most commonly → full bladder
- other causes:
- full bowel
- wounds/pressure sores
- burns
- ingrown toenails
- kinked clothing
- foreign object pressing against skin
list some symptoms of autonomic dysreflexia
- pounding HA
- goose bumps
- sweating above level of injury
- bradycardia
- skin blotching
interventions for autonomic dysreflexia
- if pt is lying down → sit them up immediately
- if already sitting remain sitting and perform pressure relief
- DO NOT LIE DOWN
- check catheter
- check clothing
- check skin
- ***initiate emergency response if not resolved within 10 minutes***
pt edu is CRUCIAL
list sequelae of autonomic dysreflexia
convulsions/seizures
LOC
death
why may there be impaired thermoregulation following an SCI?
loss of sympathetic output
the body’s ability to control blood vessel response that conserves/disspates heat is lost
- at risk for hypothermia due to peripheral vasodilation
- at risk for hyperthermia due to lack of sweat gland control
T/F: the lower the injury, the greater the distrubances in temperature control
FALSE
higher level injuries result in greater disturbances
S/S of hyperthermia
- skin feels hot and appears flushed
- feeling weak
- dizziness
- HA
- visual distrubances
- nausea
- tachycardia
- weak or irregular HR
S/S of hypothermia
- shivering
- exhaustion/drowsiness
- confusion
- slurred speech
spasticity is more common with ___________
cervical lesions
Neurological level of SCI and muscles of respiration
- C1-C2
- SCM, upper trap, cervical extensors
- C3-C4
- partial diaphragm, scalenes, LS
- C4-C8
- diaphragm, pec major/minor, SA, rhomboids, lat dorsi
- T1-T5
- some intercostals, erector spinae
- T6-10
- intercostals and abdominals
- T11 and below
- respiratory muscles intact
bladder dysfunction with SCI
alteration of reflexes and voluntary control of micturition
the level of SCI determines the type of dysfunction. Describe them
- Above conus medullaris/sacral segments → spastic/hypereflexic bladder
- voiding is involuntary and incomplete
- lesion to CM/sacral segments → flaccid/areflexic bladder
- bladder overfills and over-distends
- overflow and stress incontinence may occur
how is bladder dysfunction from SCI managed?
- external collection devices (catheters)
- Intermittent cathererizations
- medications
- surgery
- suprapubic catheter
- bladder augmentation
describe how the level of SCI impacts bowel function
- above S2 → spastic/reflex bowel
- excretment is involuntary and incomplete
- S2-S4 → flaccid/areflexive bowel
- bowel overfills and over-distends
_____ is the second most common cause of autonomic dysreflexia
bowel dysfunction
how is bowel dysfunction from SCI managed?
- reflex bowel program → trigger bulbocavernosus reflex
- digital stim program
- bowel suppositories
- pts can train their bowel to excrete at specific times of day, every single day
- usually in the morning or at night
sexual dysfunction resulting from SCI
- Males
- directly related to level and completeness of injury
- erectile capacity spared with UMN lesions but fertility can be impacted
- Females
- menstruation and fertility more likely to be spared
- can still get pregnant but will need to be in hospital for 3rd trimester
BP instability resulting from SCI
- cardiovascular dysfunction is common
- T6 and up → bradycardia, excessive peripheral vascular dilation
- Orthostasis common at all levels
- increased commonality with injuries at T6 and above
- due to lack of an efficient muscle tone AND loss of sympathetic vasoconstriction resposne in LE’s cause venous pooling in LEs
types of pain following SCI and triggers for them
Neuropathic and orthopedic
common causes → irritation and damage to neural elements, mechanical trauma, surgical interventions, poor handling and positioning
neuropathic pain following SCI
- poorly localized c/o numbness, tingling, burning, shooting, and aching pain and visceral discomfort below level of injury
- can be exaggerated by:
- noxious stimuli
- UTI
- spasticity
- bowel impaction
- cigarette smoking
orthopedic pain following SCI
common site of pain → shoulder overuse injuries and LBP
how does osteoporosis and renal calcui become a problem post SCI?
- due to changes in Ca metabolism
- decreased weight bearing may lead to demineralization of bones and decreased BMD
- can lead to vertebral compression frxs and other frxs
- calcium from bones is absorbed into blood → deposited in kidneys → kidney stone formation
how is osteoporosis and renal calcui managed post SCI?
- Preventative
- early mobilization
- therapeutic standing
- admin of Ca supplements
- good dietary management
ASIA exam steps
- determine motor level
- determine sensory level
- determine neurological level
- determine ASIA level
ASIA Exam → Motor Level
- refers to the most caudal segment with normal motor function on each side of body
- examine myotomes in UE and LE
- examine voluntary anal contraction
ASIA Exam → Sensory Level
- Refers to most caudal segment of the SC with normal sensory function on each side of body
- evaled via key sensory point within each of the 28 dermatomes on R and L
- light tough
- dull/sharp
- deel anal sensation
- evaled via key sensory point within each of the 28 dermatomes on R and L
ASIA Exam → Neurological Level
- Refers to the most caudal segment of the spinal cord with normal sensory and antigravity muscle function on both sides
- provided that there is normal/intact sensory and motor function rostrally
- helpful in predicting which parts of the body may be affected by paralysis and LOF
how is Neurologic Level in the ASIA Exam determined?
evaluating integrity of motor function, sensory function and sacral reflexes
the ASIA Exam classifies SCI as ________
A → E (with E being normal)
ASIA Exam
Classification A
Complete
- no sensory or motor function is preserved in sacral segments S4-5
- ZPP may be present
ASIA Exam
Classification B
Sensory Incomplete
- sensory but not motor function preserved below neuro level and includes the sacral segments S4-5
- light touch or pin prick at S4-5 or deep anal pressure
- AND no motor function is preserved more than 3 levels below the motor level on either side of body
ASIA Exam
Classification C
Motor Incomplete
- Motor function is preserved at the most caudal sacral segments for voluntary anal contraction
- OR the pt meets the criteria for sensory incomplete status and has some sparing of motor function more than 3 levels below the ipsilateral motor levels on either side of body
- this includes key/non-key muscle functions
- For AISA C → less than half of key muscle functions below the single NLI have a grade of >/=3
ASIA Exam
Classification D
Motor Incomplete
- Motor incomplete status with at least half of key muscle functions below the single NLI having a muscle grade of >/= 3
SCI Prognosis
- 85% of ppl with SCI who survive the first 24 hrs are still alive 10 years later
- 10-20% mortality
- mortality rates sig higher in 1st year post injury
- 2-5x more likely to die prematurely than ppl w/o SCI
- Life expectancy is 90% of normal and varies based on level of injury
- higher the injury and older the age → more negative effects on life expectance
- leading causes of death:
- pneumonia
- septicemia
