Lecture 4: Spinal cord injury (minus first 12 slides) Flashcards
Pathogensis of SCI:
Blood flow changes
* Ischemia releated to reduced blood flow, damage to blood vessels and microhemorrages, hypoxia
Inflamamtion:
* Positive and negative effects
Demyelination
* Reduced rate of axonal firing, maturation of a scar around the lesion (positive and negative effects) - if a scar forms and becomes rigid, mobility can suffer around that area (can also be protective and sealing)
Grey Matter
* Loss, fluid-filled cyst (syrinx) forms or cord collapses
Dural scarring
* Causes permanent connection of cord to dura, no longer freely mobile
Neural function
* Impacted below injury level
* If its at C6 they’ll have C6 abilities
Neuropraxia
* Athletic injury, PNS nerve damage
Syringomyelia
* Can appear over time, cyst activation and gliosis of SC, syrinx forms, cyst cavity
* can cause pressure in areas we dont want
Fluid filled aera
* can cause area of pain and numbness and tingling
Think bruising of SC
* can lead to cell death
* Sensory/motor problems
* necrossis / hemorrhage
Syringomyelia
Neurologic disorder in which a fluid filled cyst (syrinx) forms within the SC
What does dural scaring do to the SC?
Makes it less mobile
Spinal cord is impacted will they be okay at the level of the lesion
Yes, if C6 is impacted you will be okay at the level of C6, its just everything below that thats the issue
Neuropraxia
Neuropraxia is a type of nerve injury characterized by a temporary loss of function in a nerve due to compression or stretching. This condition often results in symptoms like weakness, numbness, or tingling in the affected area. Neuropraxia typically involves no structural damage to the nerve itself, and recovery usually occurs within a few hours to weeks, depending on the severity and cause of the injury.
Trauma happens
* Arteries / veins are affected (blood supply)
* Cells are affected
* Impared breathing
* Vasodilation impared inotropy
All the leads to ischemia
Notice what happens to the vertebral artery when vertebrae are affected.
* so everything below this area will be affected
What makes the cord less mobile?
Dural scaring
SCI’s are classified according to if the are complete or incomplete.
SCI’s are classified by the neurologic level of injury
* Named by most caudal level with normal sensory and motor function bilatearlly
SCI injury that has lack of sensory and motor function in the lowest sacral segment
Complete injury
SCI that has preservation of sensory and/or motor function in the lowest sacral segment
Incomplete injury
How are SCI’s names?
Named by most caudal level with normal sensory and motor function bilatearlly
What are the two ways SCI’s are classified
1) Compleite or incomplete
2) Neurologic lvl of injury
Neurologic Level of Injury - NLI
* SCI named for neurologic level of injury - NLI
* American spinal injury association distributes and maintains the international standards of neurlogical classification of SCI
Identifies sensory and motor levels indiciative of the most rostrual spinal levels demonstrating unimpared function
* Rostral levels are unimpared (toward the head)
* Named by most caudal level bilatearlly that is unimpared
28 dermatomes are assessed bulatearlly using pinprick and light touch sensation, and 10 key muscles are assessed bulatearlly w/ MMT
* Results are summed to produce overall sensory and motor scores and are used in combination w/ evaluationof anal sensory and motor function as a basis for the deternubatuib if AIS ckassufucatuib
So you’re naming it based on the most caudal thats unimpaired bilatearlly, but testing the ones above to make sure they’re uninpaired
NLI extended
A clinical examination is conducted to rate sensation as follows
* 0 = absent
* 1 = impaired
* 2 = normal
Muscle function is rated from 0 (total paralysis) to 5 (normal-active movement, full ROM against significant resistance)
The presence of anal sensation and voluntary anal contraction area ssessed as Y/N
* So thats either yes or no because they either can or cannot do it
Bilatearl motor and sensory levels and the AIS are based on the results of these examinations
AIS (5 pound ordinal scale) classifies individuals from A (complete SCI) to E (normal sensory and motor function)
* NOTE: these are reserved for people that have had a SCI wouldnt rate eachother
Preservation of function in the sacral segments (S4-S5) is key for determining the AIS score
Knowledge check: No sensory function under level os SCI =
complete
Complete loss of sensory and motor function below the level of the lesion
Complete
Complete lesions are a result of spinal cord transection, severe compression or continusion, or extensive vascular dysfunction
Partial loss of sensory and mot function below the level of the injury
* The resulting motor or sensory function is called
Incomplete
Incomplete lesions often occur when there is a contusion produced by bone framents, soft tissue, or edema within the spinal canal
The resulting motor or sensory function is also called sparing
* Know that sparing is associated w/ incomplete lesions
ASIA SCALE
A = complete
B = Sensory incomplete (you have sensory but no motor below the NLI (neurologic level of injury)
C = Motor incomplete
* Less than half of key muscles below the level of NLI have a muscle grade >/3
D = Motor incomplete
* More than half of key muscles below the level of NLI have a muclge grade >/3
E = Normal - but they had to have prior deficits
So E is the best w/ A being the worst
ASIA (AIS) scale
ASIA Scale
The circled muscles are the 10 key muscles for testing motor function
ASIA SCALE
Asia Scale sensory testing
The dots on the person are where you’re going to be sensory testing
We have a C6 sensory and motor because that is the last spot on our scale where the person got a 5 bilatearlly
* and the last time they got normal sensory as well
* C6 is the last time they got a 2 for sensory bilatearlly and a 5 for motor bilatearlly
2 = max for sensory
This is an incomplete injury
Half of the key muscles are 3/5 or greater
D
Collection of signs and symptoms that do not indicate a specific cause, resulting from tumors or truma
Syndromes
Which syndrome
Anterior cord syndrome
Which syndrome
Central cord syndrome
Which syndrome?
Brown sequard syndrome
Which syndrome?
Cauda equina syndrome
Make sure you at least know the 3 main tracts
Anterior cord syndrome
* What kind of injuries (flxn or extension)?
* Interfers w/ what 3 things?
* What is it typically caused by
* This ischemia damages which portion of the cord.
* Are problems at, below, or above the level of the lesion
* Is it bilatearl or unilatearl?
* Why is conscious proprioception and light touch information spared?
Flexion injuries
Interferes w/ pain and temperature sensation and motor control
Typically caused by a disruption of blood flow in the anterior spinal artery
Ischemia damages the anterior 2/3 of the spinal cord (because thats what the anterior spinal artery supplies)
* affects the ascending spinothalamic tract and descending upper motor neurons
* Will also damage somas of lower motor neurons
Anterior cord syndrome interfers with nociceptive (pain) temperature sensation and with motor control below the level of the lesion - bilateraly (because the artery supplies the entire front of the cord)
NOTE: Because tracts that convey conscious proprioception and light touh information are located in the posterior cord, these functions are spared (DCML)
Central Cord Syndrome
* what kind of injuries (flxn or extension)
* At what level do they typically result, as a cause of what
* In small lesionswhat do you lose and why
* In larger lesions what do you lose
* Is it more sevre in UE or LE?
Hyperextension injuries
Usually occurs at the cervical level as a result of trauma
if the lesion is small, loss of nociceptive (pain) and temperature information occurs at the level of the lesion because spinothalamic fibers crossing the midline are interrupted
Larger lesions additionally impair upper limb motor function due to the medial location of upper limb fibers in the latearl corticospinal tracts - at/below level of lesion in UE
* More severe in UE than LE, variable degree of impairement in trunk/LE’s due to integrity of SC
She said to know: small lesion = problems at level of lesion, large lesion = upper body all together is impared
* Its going to be more severe impairement in upper body, but you’re going to see some degree of problems in LE as well
Brown Sequard Syndrome
* Disruption of what part of cord?
* Segmental losses are ipsilatearl or contralataeral?
* Below the level of sensation what is lost ipsilatearlly
* Below level of lesion what is lost contralaterally
Disruption to hemisection of the cord
Results from a hemisection of the cord
Segmental (spinal segment) losses are ipsilateral and include loss of lower motor enurons and all sensations
Below th elevel of the lesion, voluntary motor contorl (corticospinal), conscious proprioceptions, and light touch (DCML) are lost ipsilatearlly; nociceptive (pain) and temperature (spinothalamic) sensation is lost contralaterally
Cauda Equina Syndrome - also called medullaris syndrome
* what muscles are affected
* Why does spasticity and hyperreflexia occur?
* Are they common?
Indicates damage to the lumbar and/or sacral spinal roots, causing sensory impairment and flaccid paresis or paralysis of lower limb msucles, bladder and bowl
Spasticity and hyperreflexia do not occur because cauda equina lesions are below the spinal cord proper and thus upper motor neurons are intact
Complete cauda equina lesions are rare
This syndrome causes low back and lower limb pain and difficulty walking, execessive lordosos, scoliosis, problems with bowel and/or bladder contorl and foot deformities
* What can it be associated w/?
Tethered cord syndrome
Associated w/ spina bifida
KNOW: A good way to dilinate tethered cord from cauda equina is that tethered cord is onset as a child, that cord is thetehred to vertebral column area = low back pain, difficulty walking etc
* During development the vertebral column grows longer than the SC
* Infrequiently the SC becomes attached to surrounding structures during early development when its still growing down
* This tethering of the SC becomes stretched which damages the cord and the cauda equina
Lower motor signs (weakness, flaccidity) occur if the anterior cauda equina (because its the spinal nerves which are lower motor neurons?) is stretched. Upper motor neuron signs (abnormal reflex, paresis and changes in skeletal muscles) occur if the SC is excessively stretched
Posterior cord syndrome
* Common or rare?
* There is loss of what that leads to what?
* Which tract is affected?
Rare
Preservation of motr function, pain. There is loss of light touch and proprioception below the level of the lesion leading to severe gait deviations?
DCML affected (this is light touch, proprioception, and vibration)
Look at the right side of this picture
Knowledge check: Which syndrome has bilateral loss of pain, temp and motor control loss below the level of the lesion
Anterior cord syndrome (remember often caused by flexion injuries)
Immediately after traumatic injury to SC, cord functions below the lesion are depressed or lost
Spinal shock
Due to the interruption of descending tracts that supply tonic faciliation to the spinal cord neurons
During spinal shock these are impaired - note this happens right after the injury to the cord - everythign becomes flacid and no more
* Somatic reflex, including stretch reflexes, withdrawl reflexes and crossed extension reflexes
* Autonomic reflexes, including smooth muscle tone and reflexive emptying of the bladder and bowel
* Autonomic regulation of BP, resulting in hypotension
* Control of sweating and piloerection is lost
During Spinal shock what happens to arterial BP?
* This indicates that the output of the sympathetic NS is _
Arterial BP drops significaintly
Sympathetic NS comlpetely interrupted
During Spinal shock what are skeletal muscle reflexes like?
How many months may it take to regain normal relexive activity after spinal shock?
Non functional
Takes several months to return to normal
In spinal shock if the transection is incomplete and some of the descending pathways remain intact what happens to some reflexes?
They may become hyperactive
KNOW: For spinal shock sacral autonomic reflexes that regulate bladder and bowel function may be suppressed for several weeks
NOTE: In an upper motor neuron injury like SCI hypertonicity is normally present. However, in spinal shock (which is right after the injury) is the opposite. Its flacid. Later on they may get some of hypertonicity
NOTE: if its an incomplete spinal cord injury that causes that shock they will initially be completely flacid then that hypertonicity will return below that level of the lesion. However, if its a complete dissecution of the SC than there will not be any tone that returns below the lvl of the lesion
Changes that we see post SCI
Lesion above _ result in paralysis of the diaphram and generally necessitate artifical ventilation because of loss of phrenic nerve innervation
C4
Just take C3,C4,C5 and go to the middle
Pulmonary complications with lesions at C5 through T12 arise as a result of loss of innervation to these two muscles
Abdominal
Intercostal muscles
Because these both help w/ expiration/inspiration
Progressive paralytic scoliosis in a chronic SC patient. Happens due to lack of muscle tone and contorl following a SCI. Through being sedintary / sitting the SC goes into some curves they shouldnt go into
* This can impaire respiration if its severe (notice the 110 cobb angle)
Knowledge check: Lesion above which neurlogic level of injury will paralize the diaphragm?
C4
obvisouly a C3 would do this as well and anything above it
Issue that is characterized by an overactive autonomic NS response due to stimuli below the level of injury
* Happens particullary with injrues at or above the _ level
* What percent of patients exerpience this when they have a lesion at or above the level above?
Autonomic dysreflexia
At or above T6
90% pts
What happens to the sympathetic NS in autonomic dysreflexia?
Increases the risk of _
What happens to BP
What do you see above the neurologic level of injury? What happens below it?
What will patient report when this happens?
What happens to vision?
Are they coherent?
Uncrolled sympthatic response
* Increased risk of stroke
* Elevated BP
* Flushing and sweating above neurologic level of injury, pallor below
* Report a severe HA
* Blurring of loss of vision
* Incoherent (could be) - there will at least be a change or an episode of something happening
A person has an episode of autonomic dysreflexia. What is it most likely releated to?
Always releated to some noxious stimulus below the neurlogic level of injury
However, 85% is urological
* think catheter backing up
* NOTE: We actaully lose the sense of the need to void w/ this kind of SCI, so thats why it backs up
This puts them at an increased risk of stroke so ints dangerous (because BP gets so high)
How much does autonomic dysreflexia increase BP?
Increased systolic BP by 40 mmHg or above baseline (>150 mmHg)
Can autonomic dysrelfexia while current spinal shock is happening?
Will happen after spinal shock has disapated
can begin any time within the first year
KNOW: In autonomic dysreflexia some noxious stimuli (think urinary) triggerys sympathetic reflex to the intermediolatearl grey columns
Lack of compensatory descending medullary parasympathetic response (vagal nerve)
generalized vasoconstriction
* Parasympathetic response occurs above the NLI (bradycardia and vasodilation)
* Sympathetic response continues below NLI
So they’re essentially getting both a sympathetic and parasympathetic response going on at the same time
4 steps of what to do w/ a pt with autonomic dysreflexia?
1) Sit the pt up
2) Remove restrictive clothing
3) Find the trigger (think urinary catehter back up - however, even tight clothing can cause it)
4) If it doesnt clear than cause 911
What is the center for urination in the spine?
* What level is it?
Conus medullaris
* Upper vertebrae (L1/L2)
Primary reflex of bowl, bladder, and sexual stuff originates from what area of the spine?
Originiates in the sacral segment
What happens to the bladder in spinal shock?
Becomes flacid, with absence of musle tone and bladder reflexes (makes sense, you’ve got nothing spinal shock)
Lesions above the conus medullaris (spinal center for urination) will cause reflexive neurogenic bladder demonstrated by _ (what happens?)
* What does this lead to in regaurds to voiding
Leads to spasticity of the bladder (makes sense, conus medularis is part of the spine so an injury here can lead to that spasticity)
Leads to voiding difficulities (cant really fill correct)
Detrusor muscle hypertrophy and urethral reflux
NOTE: UTI’s are common
What does the conus medullaris turn into?
Caudea equina
* While the conus medullaris is considered upper motor neuron, the caudea equina are spinal nerves are considered lower motor neurons
NOTE: Spastic bladder is different than a flacid one. A spastic bladder makes you hold in urine and unable to void (due to that UMN lesion = spasticity). However, if its in those LMN they’ll release the bladder and can’t hold it in because its flacid)
NOTE: sexual response is directly releated to the level and completeness of injury
Sexual function relies on pathways similar to those of the bladder and bowel
When talking about sexual function men with higher level lesion can often do what?
Achieve erection (this that spasticity) but they cannot ejaculate
What happens to erection and ejaculation w/ caudea equina lesion?
Not usually possibile
* This is considered LMN so they dont get that spastistic boner (only flacidity)
How long are menses typically interupted following a SCI? What happens to fertility and pregnancy?
3-6 months
Not interupted
Knowledge check: What is the first step in managing autonomic dysreflexia?
Sitting the pt up
* were trying to change BP response
KNOW: Prognosis for SCI depends on the level of injury, muscle strength, and ASIA at the initial injury. remember ASIA scale can change over time, but the inital is what were looking at here
Who recovers better from SCI young or old?
Young
During what timeframe does most motor recovery occur following a SCI?
6 months
The muscles graded 1 to 3 in the zone of partial preservation have potential for recovery of motor function; however, less than 50% of the most cephalad muscle grade 0/5 at initial testing regained strength at 1 year
NOTE: more than one half of the SCI population will have return of some neurlogic function
When do neurlogic recovery happen the most following a stroke 3 months quiz
What kind of fx have the most favoriable prognosis for return to function in SCI?
* What about the worst?
Compression = best
Crush (think burst) = worst
Preservation of axonal integrity and regrowth of neural tissue are anticipated to have a significant effect on the recovery and mobility after SCI
* So if these happen you’ll get better
Individuals who score _ or better on the ASIA scale ahve higher life expectancies compared with idnividuals with ASIA scores of _ - quiz question here
If you score D or better than you have a higher life expectancy than those of A, B, C.
Just know things like “A complete A has a worse life expectancy than an incomplete D”. Or a cervical injury is going to have a worse prognosis than lumbar (might need a ventilator)
Who lives longer those w/ paraplegic injuries or those w/ low cervical and higher cervical level injuries in SC?
Paraplegic (meaning lumbar/thoracic levels)
What kind of SCI pts have the lowest life expectancy?
Those who depend on ventilators
NOTE: Long term urinary tract infections continues to be a large cause of death in SCI pts, but cnontrol of sepsis has improved
Another common cause of death is respiratory diseasem specifically atelectasis and penumonia
What is the leading cause of death among SCI w/ high cervical injury?
Remember, C4 is what innervates the diaphragm. So its Pneumonia because they can’t properly clear the lungs
Knowledge check: Which pt has the best prognosis for recovery - probs something like this one quiz
* It was the one with the compression fx instead of the crush
* Younger pt better than older
* D on asia scale opposed to A
What spinal level is quadriplegia?
C1-C8
C1-C5 SCI injuries (note most of these injuries are complete instead of incomplete)
Dressing: dependent in all dressing activities
Bathing: dependent in all bathing activities
Independent with assistive devices for verbal communication (c1-3)
* meaning they can’t communicate w/o assistive devices
Assistive devices necessary for keyboarding, writing, page turning, and use of telephone
Independent verbal communication w/ what kind of cervical fx
C4-C5 = independent verbal communcation
* However, if you’re C1-C3 you’ll need assistive device for verbal communication
A quadriplegia pt is able to undress in wheelchar and be independent w/ assitive devices is what level?
C8
Makes sense because they get finger contorl at this point
What does C8 do?
Finger flexion
What level is paraplegia?
T1 and below
NOTE: level of lesion insdicates the caudal most intact spinal segment that is the nurlogic level, not the vertebral level
If someone is a C6 will they have wrist extensors?
C6 = wrist extension myotome
* They will have it because SCi injuries named for the last level of bilateral ability
* But they wouldnt have C7 (finger flexors)
Pharmacotherapy muscle relaxants
1) Diazempam (Valium)
2) Tizanidine (Zanaflex)
3) Chlorzoxaone (Parafon Forte), Cycolbenzaprine (flexeril), carisoprodol (soma), methocarbamol (robaxin), and orphenadrine (norflex)
4) Baclofen (Lioresal)
5) Dantrolene (Dantrium) (but has some side effects)
NOTE: in SCI pts muscle relaxants are often used to manage tone (however, they also have other uses)
* can be used as a general relaxant
Which muscle relaxant acts centrally in supraspinal centers and spinal neurons
* Used to treat?
* Side effects (2)
Diazepam (Valium)
Used to treat muscle spasm (doesnt necessarily mean its actually treating spasticity) - could have chronic spasms (MS) and not have spasticity
Side effects
* Drowsiness can be serious - can prevent people from driving / being independent
* Abuse can lead to withdrawl symptoms
NOTE: Drug interactions with cimetidine (tagamet, anticulare and anti stomach acid), viracept and norvir (antiviral agents), and some AIDS medications that can inhibit enzymes that metabolze diazepam. The result could be increased blood levels of diazepam.
What muscle relaxor acts on the cord as an adrenergic agonist
* what is it used to reat
* Side effect (1)
Tizanidine (Zanaflex)
used to treat spasiticity (not spasm)
Side effect is hypotension
What muscle relaxor acts at the level of the brain stem or SC?
* sued to treat
* side effects (4)
Chlorzocaone (Parafon Forte), cyclobenzaprine (Flexeril), Carisoprodol (Soma), methocarbamol (Robaxin), and orphenadrine (Norflex)
Used for temporary relief of local, acute muscle spasm
Side effects
* Similar to antidepressents such as sinequam and elavil
* All of these can interact with monoamine oxidase inhibitors such as nardil and parnate to potenally cause a hypertensive crisis
* Flexeril can also cause tachycardia, blurry vision, and dry mouth
Basically side effects seem like a sympathetic response
Which muscle relaxant inhibits release of neurotransmitters in the brain and spinal cord, especially substance P. This can reduce inflammation and pain
* How is it taken
* Used to treat
* Side effects (2)
Baclofen (Lioresal)
Taken orally and also intrathecal
Used to treat spasticiity or reduce painful flexor or extensor spasm
* So used to treat both
Side effects
* Drowsiness
* Increased seizures if patient has epilepsy
which muscle relaxant acts locally on muscle fibers to block release of calcium
Dantrium
Used for chronic spasticity
Side effects:
* Dizziness
* Drowsiness
* Diarrhea
* Photosensitivity
* Adverse effects can include toxic hapatitis (potentially fatal), seizures, tachycardia, and muscle weakness. Should not be used w/ cardiac and respiratory dysfunction because od decreased m strength
Knowledge check: Which muscle relaxants side effect is hypotension?
Tizanidine (Zanaflex)
