Spinal Cord Injury I: Overview & Neuropathology

Question 1

1. SCI is more common in males or females?
2. Mode age for SCI
3. Mean age for SCI
4. Most common cause of SCI

Answer 1

1. males
2. youngin’s (19)
3. between young and old (30)
4. MVA

Question 2

What is the order of these structures leaving the spinal cord?
spinal nerves, roots, rootlets, primary rami

Answer 2

1. Rootlets
2. Roots
3. Spinal nerves
4. Primary rami

Question 3

True/False. The sensory roots enter the spinal cord on the anterior portion and motor roots exit the spinal cord on the posterior portion.

Answer 3

False. The sensory roots enter the spinal cord on the POSTERIOR (dorsal) portion and motor roots exit the spinal cord on the ANTERIOR (ventral) portion.

Question 4

What is the normal mechanism of primary damage to the spinal cord?

Answer 4

Bruised by impingement from bony or soft tissues (fractured &/or dislocated bone, ligamentum flavum) (Does NOT have to be severed for irreversible damage to occur)
Also, damage to arteries supplying the cord can do the same thing.

Question 5

1. How long can 2° damage to the spinal cord continue?

2. What are some mechanisms of 2° damage?

Answer 5

1. Several days up to a few weeks.
2. ichemia (10-30s can cause irreversable damage
   inflammation (WBC’s releasing free radicals damaging more cells)
   Ion derangement (disrupts nerve conduction, Ca influx causes cell death)
   Accumulation of Glutamate (Causes more Ca influx, causing cell death)
   Apoptosis (unknown reasons happens after CNS damage).

Question 6

What is spinal shock and how long does it last?

Answer 6

Temporary disruption of the cord below level of lesion following injury resulting in all reflexes, sensory function, voluntary motor and autonomic control lost. It lasts for 24 hrs to 2 weeks (or 2 mo).

Question 7

Recovery is most often seen in cord fibers or nerve roots? Why? What is the best predictor of neurological return?

Answer 7

Nerve roots b/c they are more resistant to trauma and have greater ability to recover and regenerate. The best predictor is evidence of sparing below the level of lesion (as seen best in 1 month-post-injury exam b/c of spinal shock).

Question 8

How does one designate the level of SCI lesion? (from notes, Also look on ASIA form).

Answer 8

Sensation - light touch and pin pricks at “key points” in each dermatome
Motor - “Key muscles” in each myotome demonstrating: At least 3/5 in MMT AND level above demonstrates 5/5.

Question 9

Describe Sensory and Motor function in the ASIA A-E scale.

Answer 9

A: Complete: no sensory or motor in S4-S5.
B: Incomplete: Sensory below lesion presevered inc. S4-S5.
C: Motor Function 1/2 of key muscles below lesion.
D: Motor Function ≥3/5 in >1/2 of key muscles below lesion.
E: Normal sensory & motor. You healed!

Question 10

What levels do you need to have to have the diaphragm work? Above what level do you need to breathe normal?

Answer 10

“C3 to C5 keeps the diaphragm alive!” boomshockalockalocka boom boom! Also, you need T12 and above (innervation to intercostals and other accessory muscles) to breathe normally.

Question 11

What is paradoxical breathing?

Answer 11

Altered pattern of breathing by which paralysis of intercostals cause chest wall to go INWARD while breathing in instead of expanding outward.

Question 12

What 2 things does a patient need to have voluntary control of bowel/bladder?

Answer 12

1. Intact sacral spinal cord
2. Ascending and descending tracts in communication with sacral cord.
   Therefore, most SCI patients lose voluntary control.

Question 13

What are the 5 results of SCI in the cardiovascular system? What problems do these results cause?

Answer 13

1. Loss of sympathetic input to heart but parasympathetic remains. (bradycardia and bradyarrhythmias)
2. vasodilation of peripheral vasculature below level of lesion (hypotension)
3. loss of sympathetic reflexive control of BP (orthostatic hypotension)
4. Disruption of cardiovascular reflexes below level of lesion (impaired responses to exercise = decreased endurance and exercise-induced hypotension)
5. Decreased venous return to heart (2° to decreased vascular tone and loss of muscle pump). (produces left ventricular hypertrophy and decreased endurance)

Question 14

1. What level of SCI (and below) is usually free from cardiovascular complications?
2. What complications usually resolve within a few weeks of injury and what complications usually remain?

Answer 14

1. T6 and below is usually good due to good enough sympathetics.
2. Resolve: bradycardias/arrhythmias and various hypotensions. Remain: decreased CV response to exercise and decreased venous return.

Question 15

SCI patients have a tendency to have what thermoregulation problems early on? later on?

Answer 15

Early on: Hypothermia due to loss of sympathetic resulting in peripheral dilation and loss of heat
Later on: Hyperthermia due to loss of ability to sweat below level of lesion.

Question 16

Fertility of men after spinal cord? women?

Answer 16

men: infertile. women: fertile.

Question 17

What is Brown-Sequard Syndrome? What is the usual cause? What problems does it result in?

Answer 17

Hemisection of cord (usually caused by head turned then forced forward).
Ispilaterally: loss of sensation in dermatome at damaged segment, decreased DTR and superficial reflexes, clonus, Babinski +, loss of kinesthesia, proprioception and vibratory sense.
Contralaterally: loss of pain & temp beginning several segments below.

Question 18

What is Anterior Cord Syndrome? What is the usual cause? What is the clinical presentation?

Answer 18

loss of the anterior and lateral cords caused by a flexion injury in the cervical spine usually. Presents as loss of motor, pain, and temperature below level of lesion with maintenance of kinesthesia, proprioception and vibration sense.

Question 19

What is Central Cord Syndrome? What is the usual cause? What is the clinical presentation?

Answer 19

Loss of the central portion of the spinal cord caused by hyperextension injury in cervical spine. Presents as more motor then sensory loss with UE’s more affected due to their cervical tracts more central.

Question 20

What is the clinical presentation of posterior cord syndrome? What disease/condition is it associated with?

Answer 20

Presents as loss of proprioception, kinesthesia, and vibratory sense, usually develop wide-based gait pattern. Associated with tabes dorsalis (destruction of spinal cord by syphilis.)

Question 21

Why are LMN’s in cauda equina syndrome not likely to regenerate fully (4 things)?

Answer 21

1. large distance between lesion and end organ
2. Axon regeneration may not occur along original distribution
3. Glial cell-collagen scarring may block regeneration.
4. End organ may no longer function when regeneration finally occurs.

Question 22

What is “sacral sparing” and what does it indicate? What are clinical signs of it?

Answer 22

centrally located sacral tracts are preserved indicative of an incomplete lesion. Signs include perianal sensation, rectal sphincter contraction, cutaneous sensation in “saddle” and active contraction of toe flexors.