Spinal Cord Injury Flashcards
(119 cards)
Complete Spinal Cord Injury
Absence of sensory and motor function below lesion level
Incomplete Spinal Cord Injury
Involves partial preservation of sensory and motor functions below the lesion level
Better prognosis than complete SCI due to preserved axon function: occur more frequently than complete SCI
Methylprednisone
corticosteroid used for SCI to... Stabilizes cell membranes, Decreases inflammation, Increases nerve impulse generation, Improves blood flow to the damaged area; Must be administered in first 3-8 hours after injury
Common causes of SCI
Transection
Compression
Infection
Degenerative Disorders
Transection
Complete severance of the cord;
All sensory & motor information is interrupted at or below lesion level
Causes of Transection
Traumatic injury including: Auto accidents Knife wounds Gun shot wounds Diving accidents
Compression
Impingement of the cord;
Symptoms depend on the severity of the injury
Causes of Compression
Trauma
Tumor
Vertebral degenerative joint disease
Infection
May compromise the integrity of the cord;
Polio is an example
Degenerative Disorders
Can damage the SC tracts;
Example: Amyotrophic lateral sclerosis (ALS) results in bilateral degeneration of the ventral horn & pyramidal tracts;
Involves both LMN and UMN damage
SCI Non-Traumatic
10%- Most likely to occur with narrowing spinal canals;
Possible Causes: disc prolapse, vascular insult, neoplasm, RA, radiation, spinal stenosis, cardiac arrest, aortic aneurysm, infection
SCI Traumatic
Most involve a single level or limited number of contiguous vertebrae;
Result from forces that create violent motions of head or trunk:
MVA, jumps, falls, athletic injury, diving accidents or GSW’s
Traumatic Cervical Injury
C5 and C7 most often areas of injury;
Flexion, vertical loading, and extension accompanied by rotation or lateral flexion
Traumatic Thoracic Injuries
Less likely to be injured due to rib cage; T12-L1 junction is most common site of injury;
Flexion motion or vertical compression can cause wedge compression or burst fractures of the vertebral bodies damaging the spinal cord
Traumatic Lumbar Injuries
Usually incomplete due to large vertebral canal and good vascular supply; Most injuries occur at L1 or L2 levels, below these levels the cauda equina is less likely to sustain a complete injury
Neuropathology
Most damage is caused by secondary sequelae of initial trauma beginning progressive tissue destruction within the cord; travels up or down 1-3 segments
Mechanism of Secondary Tissue Destruction
Ischemia, Edema, Demyelination and destruction
Ischemia
decreased blood flow to traumatized area may be due to chemicals in the body that cause vasoconstriction or thomboses, metabolic disturbances or elevated pressure due to edema
Edema
abnormal concentrations of sodium and potassium in the extracellular tissue. causes an increase in osmotic pressure in the damaged area of the cord and creates excessive edema in this area.
Demyelination and destruction
calcium ions accumulate in the injured cells. This disrupts functioning and causes demyelination and destruction of the cell membrane and axonal cytoskeleton. The necrosis of axons then progresses to scar tissue formation
Spinal Shock
Temporary phenomenon that occurs after trauma to the spinal cord in which the cord ceases to function below the lesion
How long does it take spinal shock to resolve?
Within 24 hours of injury
What does sparing of sensation or voluntary motor function indicate?
lesion is incomplete
Paraplegia
only lower extremities are involved, resulting in weakness (paraparesis) or paralysis