SCI Flashcards
SCI: etiology / mechanisms / patho
Etiology: Partial or complete disruption of spinal cord resulting in “paralysis”, sensory loss, altered autonomic and reflex activities
Mechanisms:
- traumatic: MVA (most common), jumps/falls, diving, gunshot
- mechanisms: flexion (most common lumbar), flexion-rotation (most common cervical), compression, hyperextension
- non-traumatic: disc prolapse, vascular insult, cancer, infection
Greatest frequency of injury: C5, C7, T12, L1
Pathophysiology:
- Primary: Interruption of blood flow
- Secondary (sequelae): ischemia, edema, demyelination and necrosis of axons, progressing to scar tissue formation
SCI: Classification
Level of Injury: UMN lesion
- lesion level indicates most distal uninvolved nerve root segment with normal fxn; mm must have grade of at least 3+/5 or fair+ fxn
- tetraplegia/quadriplegia: occurs between C1 and C8; involves all four extremities and trunk
- paraplegia: occurs between T1 and T12/L1; involves both LE and trunk (varying levels)
Degree of injury:
- complete: no sensory or motor fxn below level of injury
- incomplete: preservation of sensory or motor fxn below level of injury; spotty sensation; some m fxn
- ASIA Impairment Scale
ASIA A
Complete, no MOTOR or SENSORY function is preserved in the sacral segment S4-5
Complete bilateral loss of ALL sensory modalities
Bilateral loss of MOTOR function with SPASTIC paralysis below level of lesion
Loss of bladder and bowel functions with “SPASTIC” bladder and bowel
***When the bladder fills with urine, an unpredictable reflex automatically triggers it to empty; this usually occurs when the injury is above the T12 level. With a spastic bladder you do not know when, or if, the bladder will empty.
ASIA B
INCOMPLETE
SENSORY but not motor function is PRESERVED below the neurological level
Includes sacral segment S4-5
ASIA C
INCOMPLETE
MOTOR functional is PRESERVED below neurological level
most key mm below the neurological level have a m grade of LESS THAN 3/5
ASIA D
INCOMPLETE
MOTOR function is PRESERVED below neurological level
most KEY MUSCLES below the neurological level have a muscle grade of 3 OR MORE
ASIA E
Normal: MOTOR AND SENSORY
Function is normal
Clinical Syndromes:
Central cord syndrome
loss of more centrally located cervical tracts/arm function, with preservation of more peripherally located lumbar and sacral tracts/ leg fxn
Cavitation ofo central cord in cervical section
loss of spino-thalamic tracts with B loss of pain/temp
loss of ventral horn with B loss of motor function: primarily UE
preservation of proprioception and discriminatory sensation
typically caused by hyperextension injuries to the c-spine
Clinical Syndromes:
Brown-Sequard syndrome
hemisection of spinal cord typically caused by penetration wounds (gunshot, knife) with asymmetrical Sx
IL loss of DORSAL COLUMNS with loss of tactile discrimination, pressure, vibration and proprioception
IL loss of CORTICOSPINAL tracts with loss of motor fxn and spastic paralysis below level of lesion
CL loss of SPINAL THALAMIC tract with loss of pain and temp below level of lesion or lesion level, B loss of pain/temp
Clinical Syndromes:
Anterior cord syndrome
damage is mainly in anterior cord, resulting in loss of motor function, pain and temperature with PRESERVATION of light touch, proprioception and position sense (dorsal columns)
Loss of Lateral Cortico-spinal tracts with bilateral loss of motor function, spastic paralysis below level of lesion
Loss of Spino-thalamic tract with bilateral loss of pain and temperature
Preservation of dorsal columns: proprioception, kinesthesia, and vibratory sense
Typically caused by FLEXION injuries of the CS
Clinical Syndromes:
Posterior cord syndrome
Loss of posterior columns with PRESERVATION of MOTOR function, sense of pain and light touch
Bilateral loss of proprioception, vibration, pressure, and epicritic sensation (stereognosis, 2-point discrimination)
Preservation: motor function, pain and light touch
Extremely rare
Clinical Syndromes:
Cauda-Equina syndrome
—Injury below L1, variable nerve root damage (motor and sensory signs); incomplete lesions common
—Flaccid paralysis with no spinal reflex activity
—Flaccid paralysis (non-reflex) bowel and bladder
—AN LMN lesion with “AUTONOMOUS” or “NON-REFLEX” bladder
—A flaccid bladder means that the reflexes of the bladder muscles are “sluggish or absent”; it can become over-distended, or stretched. Stretching affects the muscle tone of the bladder. It also may not empty completely
—Potential for regeneration (often incomplete), slows and stops after about 1 yr
Sacral sparing
Sparing of tracts to sacral segments, with PRESERVATION of peri-anal sensation, rectal sphincter tone, or active TOE FLEXION
SCI: Exam
—Assess VS
—Respiratory Function: Respiratory insufficiency or failure occurs in lesion above C4 (phrenic nerve), assess action of the diaphragm, respiratory muscle, intercostals, chest expansion, breathing pattern, cough, vital capacity
—Skin integrity: check for areas of high pressure
—Muscle tone,spasms, and DTRs
—Sensation/ SC level of injury: check to see if sensory level corresponds to motor level of innervation (may be different in incomplete lesions)
—Muscle strength/ SC level of injury: lowest segmental level of innervation includes muscle strength present at a FAIR+ grade (3+/5)***Use caution when doing MMT in acute phase with spinal immobilization.
—Functional Status: Full functional assessment posible only when patient is CLEARED for activity and active REHAB.
Changes associated with SCI:
spinal shock
transient period of REFLEX depression and FLACCIDITY; may last several hours or 24 weeks
