Spine

Question 1

Sensory peripheral nerves enter the spinal cord via what?

Answer 1

Dorsal nerve root

Question 2

Motor and autonomic neurons exit the spinal cord via what?

Answer 2

Ventral nerve root

Question 3

What is a ganglion?

Answer 3

Collection of cell bodies OUTSIDE of the CNS

Question 4

What is Grey matter?

Answer 4

Contains neuronal cell bodies
Processing center for afferent signals that arrive from periphery

Question 5

What is white matter?

Answer 5

Contains the axons of the ascending and descending tracts

(Divided into the dorsal, lateral, and central columns)

Question 6

What are the 4 sensory tracts?

Answer 6

Dorsal column: ci eat us and gracilis

Tract of Lissauer: pain and temperature

Lateral spinothalamic tract: pain and temp

Ventral spinothalamic tract: crude touch and pressure

Question 7

What are the two motor tracts?

Answer 7

Lateral corticospinal tract: limb motor

Ventral corticospinal Tract: posture motor

Question 8

What are some traits about the dorsal column?

Answer 8

Mechanoreceptive sensations (fine touch, vibration, pressure)

Capable of two-point discrimination

Contains LARGE MYELINATED fibers

Transmits faster than anterolateral system

Question 9

Which mechanoreceptor can discriminate between two points?

Answer 9

Meissner’s corpuscles

Question 10

Which mechanoreceptor is related to continuous touch?

Answer 10

Merkel’s discs

Question 11

Which mechanoreceptor relates to proprioception, prolonged touch and pressure?

Answer 11

Ruffini’s endings

Question 12

Which mechanoreceptor is related to vibration?

Answer 12

Pacinian corpuscles

Question 13

What is the order of transmission in the dorsal column?

Answer 13

Usually an a-beta neuron

First order: enters spinal cord via dorsal root > ascends in same side > synapses with second order neuron in the medulla (cuneate and gracile nuclei)

Second order: cross side in medulla > thalamus > synapses with 3rd order in the thalamus relay station

Third order: advance towards somatosensory cortex in post central gyrus

Question 14

What is the pathway via the spinothalamic tract?

Answer 14

Mostly A-delta or C-fibers

1st order neuron: cell body is in dorsal root ganglion > may ascend 1-3 levels before synapsing with second order

Second order: crosses sides in the spinal cord and ascends via two paths > anterior spinothalamic or lateral spinothalamic > synapse with 3rd in the RAS and thalamus

3rd order: pass through thalamus and advance to somatosensory cortex

Question 15

With the corticospinal tract, if an injury happens above the decussation (crossing) what will result?

Answer 15

Spastic paralysis on the CONTRALATERAL side

Question 16

With the corticospinal tract, if an injury happens below the decussation (crossing) what will result?

Answer 16

Flaccid paralysis on the IPSILATERAL side

Question 17

What is the corticospinal tract also called?

Answer 17

Pyramidal tract

Question 18

What is the path of transmission in the corticospinal tract?

Answer 18

Motor neurons begin in cerebral cortex and synapse with lower motor neurons in the ventral horn

Question 19

Injury to an upper motor neuron results in what?

Answer 19

Contralateral spastic paralysis and hyperreflexia

(Cerebral palsy and ALS)

Question 20

What does the babinski sign test?

Answer 20

Corticospinal integrity

Question 21

What does a negative babinski test say?

Answer 21

Corticospinal tract is INTACT ~ GOOD sign

Produces a downward motion of the toes (toes curl)

Question 22

What does a positive babinski test determine?

Answer 22

Damage to corticospinal tract ~ BAD sign

Upward extension of the big toe with fanning of the other toes

Question 23

Where does lower motor neurons begin?

Answer 23

Ventral horn and end at the neuromuscular junction

Question 24

What will result in a LOWER motor neuron injury?

Answer 24

Ipsilateral flaccid paralysis

(Impaired reflexes and flaccid paralysis)

**babinski sign is absent in a lower motor injury

Question 25

What does SSEPs monitor?

Answer 25

Dorsal column (posterior blood flow)

Question 26

What do MEPs monitor?

Answer 26

Monitor the integrity of the corticospinal tract (anterior perfusion)

Question 27

What is the triad to spinal cord injury? Aka neurogenic shock?

Answer 27

Hypotension Bradycardia Hypothermia (This lasts 1-3 weeks)

Question 28

What does impairment to the cardioaccelerator fibers cause?

Answer 28

Unopposed vagal tone ~ resulting in bradycardia and reduced inotropy

Question 29

What is hypothermia the results of in neurogenic shock?

Answer 29

Impairment of the sympathetic pathways ~ inability of cutaneous vasculature to vasoconstrict, cause a redistribution of blood flow towards the periphery and allowing more heat to escape

Question 30

What is the difference b/t neurogenic shock and hypovolemic shock?

Answer 30

Neurogenic: hypotension, bradycardia, warm, pink extremities Hypovolemic: hypotension, tachycardia, cool clammy extremities

Question 31

What is the vasopressors of choice in neurogenic shock?

Answer 31

LEVO and volume expansion

Question 32

What is the major cause of morbidity and mortality in patients with cervical and upper thoracic lesions?

Answer 32

Ineffective alveolar ventilation and the inability to clear secretions.

Question 33

What is autonomic hyperflexia?

Answer 33

Following a spinal cord injury (and spinal shock) the body begins to mend itself in a pathological and disorganized way. reflexes returns but are not inhibited in any way ~ results in an overactive state.

Question 34

What % of patients (with an injury above T6) will develop autonomic hyperreflexia?

Answer 34

85%

Question 35

What are some common events that cause autonomic hyperreflexia?

Answer 35

Stimulation of the hollow organs (bladder, bowel, uterus) Bladder catherization Surgery (cysto) Bowel mov. Childbirth

Question 36

What is the classic presentation of autonomic hyperreflexia?

Answer 36

Hypertension and bradycardia

Question 37

Where does vasoconstriction occur in autonomic hyperreflexia?

Answer 37

Below the level of injury

Question 38

Where does vasodilation occur in autonomic hyperreflexia?

Answer 38

Above the level of injury

Question 39

What are some other S&S of spinal cord injury?

Answer 39

Nasal stuffiness Hypertension (headache and blurred vision) Severe HTN: stroke, seizure, LV failure, pulmonary edema

Question 40

What is the best management for autonomic hyperreflexia?

Answer 40

Prevention!!! (Then either a GA or Spinal)

Question 41

How is hypertension best treated with? In AH following SCI

Answer 41

Removal of the stimulus Deepening of the anesthetic Rapid-vasodilator

Question 42

How is bradycardia best treated in AH following SCI?

Answer 42

Atropine or Glyco

Question 43

What is amyotrophic lateral sclerosis (ALS)?

Answer 43

Progressive degeneration of motor neurons in the corticospinal tract. Both upper and lower neurons are affected.

Question 44

S&S of ALS?

Answer 44

Upper neurons involvement: spasticity, hyperreflexia, loss of coordination Lower neuron involvement: musc weakness, fasciculations, atrophy

Question 45

Where does ALS typically begin?

Answer 45

Hands

Question 46

What is the only drug that reduces mortality in ALS?

Answer 46

Riluzole (NMDA antagonist)

Question 47

What is the most common cause of death in ALS?

Answer 47

Resp failure

Question 48

How should an anesthetic provider approach paralysis for a patient with ALS?

Answer 48

NO SUX Increased sensitivity to NMB