B7.015 Selective Vulnerability from the Spinal Cord

Question 1

UMN damage symptoms

Answer 1

increased muscle tone
no atrophy
hyperreflexia
pathological reflexes present

Question 2

LMN damage symptoms

Answer 2

decreased muscle tone
atrophy
hyporeflexia
pathological reflexes absent

Question 3

reflex grading scale

Answer 3

0: no reflex
1: reflex only with reinforcement
2: reflex without reinforcement
3: reflex spreads to other muscles
4: clonus
+ if high amplitude
- if low amplitude

Question 4

normal plantar response

Answer 4

toes down (flexion)

Question 5

abnormal plantar response

Answer 5

Babinski sign
toes up and fanned
exaggerated withdrawal response

Question 6

use of Babinski sign in UMN damage

Answer 6

moderate sensitivity (60-70% have it with an UMN injury)
high specificity

Question 7

what type of midline structural lesion would cause bilateral arm and leg weakness

Answer 7

high cervical spinal cord lesion

Question 8

why should you consider midline lesions first

Answer 8

typically more dangerous and require more urgent therapy

Question 9

dorsal horn

Answer 9

sensory

Question 10

ventral horn

Answer 10

motor

Question 11

what is present in the central gray matter

Answer 11

sensory dorsal cells

motor ventral cells

Question 12

what is present in the peripheral white matter

Answer 12

intersegmental communications

“long tracts”

Question 13

why do cervical and lumbar sections of the spinal cord have large ventral horns?

Answer 13

innervate limbs which require more motor control than the abdominal area (thoracic cord)

Question 14

why is there a 3rd small out pouching between the dorsal and ventral horns in the thoracic cord

Answer 14

region where the sympathetic neurons exit the cord

Question 15

orientation of lateral corticospinal tract in the cord

Answer 15

on lateral side of the cord, between dorsal and ventral horns
leg nerves lateral
arm nerves medial

Question 16

2 neurons of the corticospinal tract

Answer 16

UMN

LMN

Question 17

3 neurons of the DCML system

Answer 17

1. dorsal root ganglion
2. nucleus gracilis or cuneatus (corticomedullary junction)
3. thalamus

Question 18

orientation of the DCML system in the cord

Answer 18

on dorsal side in between the 2 dorsal horns

wedge shaped area

Question 19

acute B1 deficiency

Answer 19

Wernicke Korsakoff

targets: mamillary bodies, medial dorsal nucleus of the thalamus, peri aqueductal structures

Question 20

chronic B1 deficiency

Answer 20

dry beriberi

targets: peripheral nerves

Question 21

B3 deficiency

Answer 21

pellagra

targets: cerebrum (dementia)

Question 22

B6 deficiency

Answer 22

pyridoxine deficiency
may be caused by isoniazid
targets: peripheral nerves

Question 23

B12 of Cu deficiency

Answer 23

subacute combined degeneration

targets: posterior columns, corticospinal tract

Question 24

vitamin E deficiency

Answer 24

vitamin E deficiency
due to fat malabsorption
targets: neuropathy, retinopathy, spinocerebellar tracts

Question 25

indications of Cu or B12 deficiency

Answer 25

``` macrocytic anemia bariatric surgery (impairs absorption) zinc supplementations (competes with Cu for absorption) ```

Question 26

treatment of Cu deficiency

Answer 26

stop zinc supplements copper replacement -IV infusion -oral

Question 27

why do we see consistent patterns of structural selective vulnerability

Answer 27

shared anatomy - proximity - blood supply

Question 28

why do we see consistent patterns of toxic metabolic selective vulnerability

Answer 28

shared physiology - toxin sensitivity - metabolic insult insensitivity

Question 29

3 neurons of ALS system

Answer 29

1. dorsal root ganglion 2. dorsal horn 3. thalamus

Question 30

orientation of ALS system in the spinal cord

Answer 30

anterior section slightly lateral to the anterior horns

Question 31

deficits with hemi-section loss of the thoracic spinal cord

Answer 31

contralateral pain and temp loss ipsilateral proprioceptive loss ipsilateral weakness

Question 32

C5 weakness

Answer 32

deltoid infraspinatus biceps

Question 33

C5 reflex

Answer 33

biceps | pectoralis

Question 34

C6 weakness

Answer 34

wrist extensors | biceps

Question 35

C6 reflex

Answer 35

biceps | brachioradialis

Question 36

C7 weakness

Answer 36

triceps

Question 37

C7 reflex

Answer 37

triceps

Question 38

L4 weakness

Answer 38

iliopsoas | quads

Question 39

L4 reflex

Answer 39

patellar tendon (knee jerk)

Question 40

L5 weakness

Answer 40

foot dorsiflexion big toe extension foot eversion, inversion

Question 41

L5 reflex

Answer 41

none

Question 42

S1 weakness

Answer 42

foot plantar flexion

Question 43

S1 reflex

Answer 43

Achilles tendon (ankle jerk)

Question 44

cervical mantle

Answer 44

area where C5-T1 dermatomes get pulled out into arms and the neck to check jumps from C4 to T2

Question 45

levels of pain and temp loss in relation to a lesion

Answer 45

several levels below (travel up a few levels before decussation)

Question 46

areas affected by posterior spinal artery infarction

Answer 46

bilateral proprioceptive loss

Question 47

areas affected by anterior spinal artery infarction

Answer 47

bilateral pain and temperature loss and weakness

Question 48

deficits seen in cervical central cord syndrome

Answer 48

pain and temp loss in upper extremities only (suspended loss) NO proprioceptive loss LMN loss in upper extremities UMN loss in lower extremities

Question 49

deficits seen in external compressive lesion of cervical spinal cord

Answer 49

usually corticospinal tract damage - selectively vulnerable for an unknown reason - bilateral spasticity and mild weakness without sensory change

Question 50

causes of subacute combined degeneration

Answer 50

B12 def Cu def Friedrich's ataxia (also have spinocerebellar involvement)

Question 51

deficits seen in subacute combined degeneration

Answer 51

corticospinal and DCML only bilateral, symmetric proprioceptive loss and weakness (pain and temp is fine)

Question 52

deficits seen in primary lateral sclerosis

Answer 52

corticospinal tract only UMN weakness alone -bilateral symmetric weakness

Question 53

deficits seen in amyotrophic lateral sclerosis

Answer 53

corticospinal and anterior horn cell involvement | UMN and LMN weakness

Question 54

conditions that cause anterior horn cell deficits

Answer 54

spinal muscular atrophy | poliomyelitis

Question 55

deficits seen with anterior horn cell damage

Answer 55

LMN weakness alone | bilateral, symmetric

Question 56

conditions that cause posterior column deficits

Answer 56

``` Tabes dorsalis (tertiary syphilis) B6 intoxication paraneoplastic (sensory neuropathy) ```

Question 57

deficits seen with posterior column damage

Answer 57

bilateral, symmetric proprioceptive loss

Question 58

conditions that can cause multifocal deficits

Answer 58

transverse myelitis | multiple sclerosis