Spinal Cord Lesions

Question 1

What is syringomyelia?

Answer 1

Cystic degeneration of the spinal cord

Question 2

How does syringomyelia arise?

Answer 2

Arises with trauma or in association with Arnold-Chiari malformation

Question 3

At what level of the spinal cord does syringomyelia usually occur?

Answer 3

C8 - T1

Question 4

Clinical presentation of syringomyelia

Answer 4

Sensory loss of pain and temperature with sparing of fine touch and position sense in the upper extremities

The cyst initially only involves the anterior white commissure of the spinothalamic tract while sparing the dorsal column

Question 5

Syrinx expansion results in involvement of spinal tracts other than the spinothalamic tract leading to:

Answer 5

• Muscle atrophy and weakness with decreased muscle tone and impaired reflexes
  
  • Due to damage to LMN of the anterior horn
• Horner syndrome
• Ptosis
• Miosis
• Anhidrosis
• Due to disruption of lateral horn of the hydrothalamospinal tract

Question 6

What it poliomyelitis?

Answer 6

Damage to the anterior motor horn due to poliovirus infection

Question 7

Clinical presentation of poliomyelitis

Answer 7

LMN signs:

• Flaccid paralysis with muscle atrophy
• Fasciculations
• Weakness with decreased muscle tone
• Impaired reflexes
• Negative Babinski sign

Question 8

What is Werdnig-Hoffman Dz?

Answer 8

Inherited degeneration of the anterior motor horn

Autosomal recessive

Question 9

Clinical presentation of Werdnig-Hoffman

Answer 9

Floppy-baby

Death occurs within a few years

Question 10

What is amyotrophic lateral sclerosis (ALS)?

Answer 10

Degenerative disorder of upper and lower motor neurons of the corticospinla tract

Question 11

Anterior motor horn degeneration leads to what motor damage?

Answer 11

LMN damage

Question 12

What are the LMN signs?

Answer 12

Flaccif paralysis with muscle atrophy

Fasciculations

Weakness with decreased muscle tone

Impaired reflexes

Negaive Babinski signs

Question 13

Degeneration of the lateral corticospinal tract leads to damage of what neurons?

Answer 13

UMN damage

Question 14

What are the UMN damage signs?

Answer 14

Spastic paralysis with hyperreflexia

Increased muscle tone

Positive Babinski sign

Question 15

What are the signs of ALS?

Answer 15

Atrophy and weakness of hands is an early sign

Question 16

How do you disntiguish ALS from syringomyelia?

Answer 16

ALS has a lack of sensory impairment

Question 17

What mutation is present in some familial cases of ALS?

Answer 17

Zn-Cu superoxide dismutase mutation (SOD1)

Leads to free radical injury in neurons

Question 18

What is Friedrich Ataxia?

Answer 18

Degenerative disorder of the cerebellum and spinal cord

Question 19

Clinical presentation of Friedrich Ataxia

Answer 19

Degeneration of the cerebellum leads to ataxia

Degeneration of multiple spinal cord tracts leads to loss of vibratory sense and proprioception, muscle weakness in the lower extremities and loss of deep tendon reflexes

Question 20

What gene disorder causes Friedrich Ataxia?

Answer 20

Expansion of an unstable trinucleotide repeat (GAA) in the frataxin gene

Autosomal recessive

Question 21

What is the role of the frataxin gine?

Answer 21

Essential for mitochondrial iron regulation

Loss of the frataxin gene results in iron buildup wiht free radical damage

Question 22

At what age does Friedrich Ataxia present?

Answer 22

Early childhood with patients wheelchair bound within a few years

Question 23

What condition is associated with Friedrich Ataxia?

Answer 23

hypertrophic cardiomyopathy

Question 24

What signals are carried on the spinothalamic tract?

Answer 24

Pain and temperature sensation

Question 25

Describe the spinothalamic tract pathway from 1st order to 3rd order neuron

Answer 25

1st order neuron: Peripheral nerves to posterior horn; Cell body is in dorsal root ganglion

2nd order neuron: Arises from the posterior horn, immediately crosses over in the anterior white commissure and acends via the spinothalamic tract to the thalamus

3rd order neuron: Thalamus to cortex

Question 26

What signals are carried on the dorsal column-medial lemniscus (DCML) tract?

Answer 26

Pressure

Touch

Vibration

Proprioception

Question 27

Describe the pathways of the DCML tract

Answer 27

1st order neuron: Peripheral nerves to medulla via the dorsal column; Cell body is in the dorsal root ganglion

2nd order neuron: Arises from the medulla, crosses over and ascends via the medial lemniscus to thalamus

3rd order neuron: thalamus to cortex

Question 28

What signals are carried on the lateral corticospinal tract?

Answer 28

Voluntayr movement

Question 29

Describe the lateral corticospinal tract pathway

Answer 29

1st order neuron: Pyramidal neurons in cortex descend, cross over in medullar pyramids and synapse on the naterior motor horn of the cord (UMN)

2nd order neuron: Arises from the anterior motor horn and synapses on muscle (LMN)

3rd order neuron: None

Question 30

What signals are carried on the hypothalamospinal tract?

Answer 30

Sympathetic input of the face

Question 31

Describe the pathway of the hypothalamospinal tract

Answer 31

1st order neuron: Arises from the hypothalamus and synapses on the lateral horn at T1

2nd order neuron: Arises from lateral horn at T1 and synapses on the superior cervical ganglion (sympathetic)

3rd order neuron: Superior cervical ganglion to eyelids, pupil, and skin on face