Spinal Cord Injury: Pathophysiology Flashcards
What areas of the c-spine are most often involved in SCI, and what are some common MOIs?
- C4-C7
- Flexion + rotation (#1)
- Vertical loading
- Extension + rotation
- Lateral flexion
- Hyperextension
What areas of the T-spine are most often involved in SCI, and what are some common MOIs?
- T12-L1
- Flexion or vertical compression
Less likely to be traumatic
What areas of the L-spine are most often involved in SCI, and what are some common MOIs?
- L1
- Flexion
Typically incomplete
Tetraplegia
- Injury c-spine
- Involvement of all 4 extremities
Paraplegia
- Thoracic or lumbar regions
- Involved BLE and trunk
Complete SCI
- Absence of sensory and motor function below lesion level (ZPP possible)
Incomplete SCI
partial preservation of sensory and motor functions below level of lesion
Who has a better prognosis, complete or incomplete SCI?
Incomplete
Define zones of partial preservation
Dermatomes and myotomes caudal to the sensory and motor level that remains partially innervated.
Where are the most common sites and types of SCI overall?
- Cervical (C5-C7) and thoracolumbar junctures (T12-L1)
- Incomplete tetraplegia
Which occurs more frequently, complete or incomplete paraplegia?
Both about equal
What is the primary goal of acute medical management of SCI?
Stabilize the spine
How is the primary medical management of SCI achieved?
- Surgery (reduction or compression)
- External support devices
How does methylprednisone impact prognosis for incomplete SCI?
enhances return of some function below spinal level
How does methylprednisone impact prognosis for complete SCI?
increases changes of return of function of last preserved spinal level (1 level)
What is the function of methylprednisone for SCI?
- Stabilizes cell membranes
- Decreases inflammation
- Increased nerve impulse generation
- Improved blood flow to damaged area
When does methylprednisone need to be administered for SCI?
3-8 hours post-injury
What are some pathological secondary sequalae of SCI that the medical team must work
diligently to manage?
- Ischemia (direct and indirect)
- Edema
- Demyelination and necrosis of axons progressing to scar tissue
What is spinal shock?
temporary phenomenon with injuries T6 and above in which cord in its entirety ceases to function below lesion.
What characteristics are associated with spinal shock?
- Absent: spinal reflexes, voluntary motor control, sensory function, autonomic control below level of lesion
- Initially increased BP then drop in BP, HR, hypothermia, venous stasis
When does spinal shock resolve?
Within 24 hours to several days post injury
How doe we know spinal shock is starting to resolve?
Sacral/anal reflexes begin to return.
What is autonomic dysreflexia?
over-activity of the autonomic nervous system with damage to T6 or above.
What causes autonomic dysreflexia?
irritating stimulus introduced to body below level of spinal cord injury.
What is the most common cause of autonomic dysreflexia?
Full bladder
(Others: wound/pressure sores, burns, ingrown toenails, kinked clothing, foreign object pressing against skin)
What are the symptoms of autonomic dysreflexia?
- Pounding HA
- Goose bumps
- Sweating above level of injury
- Bradycardia
- Skin blotching
If you think your patient is demonstrating autonomic dysreflexia, what should you do?
- Sit them up! (DO NOT LIE DOWN)
- Perform pressure relief
- Check catheter
- Check clothing
- Check skin
- Initiate emergency response if not resolved within 10 min
What are the more dangerous sequelae of autonomic dysreflexia?
Seizures, LOC, death
Why do we see impaired thermoregulation with some SCI?
- loss of sympathetic output (damage to T6 or above)
Body lost the ability to control blood vessel responses that conserve or dissipate heat or shiver.
What are the signs and symptoms of hyperthermia?
- Skin feels hot and appears flushed
- Feeling weak
- Dizziness
- HA
- Visual disturbance
- Nausea
- Tachycardia
- Weak or irregular HR
What are the signs and symptoms of hypothermia?
- Shivering
- Exhaustion/drowsiness
- Confusion
- Slurred Speech
What types of patient education are critical with impaired thermoregulation?
Weather appropriate clothing
Is spasticity common with this patient population?
~65% of SCI patients will experience spasticity, more common with c-lesions
Why do we see pulmonary dysfunction with this patient population?
If injury is in T10 or above the diaphrahm/accessory muscles lost control
With what level can we expect normal ventilatory and respiratory function?
T10 and below
How does bladder dysfunction differ between SCI levels?
level of SCI determines type of dysfunction
Bladder dysfunction when lesion is above conus medullaris/sacral dysfunction.
- Spastic/hypereflexic bladder
- Voiding is involuntary and incomplete
Bladder dysfunction when lesion is at or below conus medullaris/sacral dysfunction.
- Bladder overfills and overdistends
- Overflow and stress incontinence may occur
Bladder dysfunction management
- Exeternal collection devices (catheter)
- Intermittent catheterizations
- medicaion
- Surgery: suprapubic catheter, bladder augmentation
How does bowel dysfunction differ between SCI levels?
- Above S2: spastic/reflex bowel (excremet is involuntary and incomplete)
- S2-S4: flaccid/areflexive bowel (bowel overfills and over-distends)
How do we manage bowel dysfunction?
Reflex bowel programs: digital stem programs and bowel suppositories
Why is bowel and bladder dysfunction so important with SCI care?
Can lead to autonomic dysreflexia
Bowel is 2nd most common cause!
What are the symptoms of bladder and bowel dysfunction?
- Fever
- Chillds
- Nausea
- HA
- Increased spasticity
- Autonomic dysreflexia
- Dark or bloody urine
What are some of the more common presentations of sexual dysfunction post SCI for
males?
Erectile capcity spared with UMN lesion, but fertility can be impacted.
What are some of the more common presentations of sexual dysfunction post SCI for
females?
Menstruation and fertility more likley to be spared (pregnancy is high risk)
What are common issues seen regarding blood pressure management post SCI?
- T6 and up: persistent bradycardia, excessive peripheral vascular dilation
- Orthostasis common with all level (increased risk T6 and up)
Why are BP issue common with SCI?
- Cardiovascular dysfunction
- lack of efficient muscle tone
- Loss of sympathetic vasoconstriction response in LE’s = venous pooling
How can we intervene with irregular BP? What is most effective?
- Abdominal binder
- TED stocking
- ACE wraps
- Monitor fluid intake
What types of pain do we see with SCI?
Neuropathic and orthopedic
What are common causes of SCI pain?
- irritation and damage to neural elements
- Mechanical trauma
- Surgical interventions
- Poor handling/positioning
What might a patient with neuropathic pain complain of?
- Pooly localized
- Numbness, tingling, burning, shooting, aching pain + visceral disomfort below level of injury
What can exaggerate neuropathic pain in SCI?
- Noxious stimuli
- UTI
- Spasticity
- Bowel impaction
- Cigarette smoking
SCI orthopedic pain is common in what regions?
SHOULDER, low back
Why do we see an increased risk for osteoporosis and renal calculi post SCI?
- Changes in calcium metabolism (Decreased BMD > Ca to blood > kidneys)
- Decreased weight bearing
