Ataxia & Paresis

Question 1

Where does the spinal cord end in relation to the vertebral column and what fills the gap?

Answer 1

Spinal cord ends in most dogs around L6 and around L7 in cats
so there is no spinal cord present at the lumbosacral junction (instead it is occupied by the cauda equina)

Question 2

What are the four functional segments of the spinal cord?

Answer 2

[divided based on their corresponding vertebrae and LMN’s]
C1-C5
C6-T2
T3-L3
L4-S3

Question 3

How does the spinal cord control bladder function?

Answer 3

At T3-L3 is the hypogastric nerve which controls bladder relaxation and sphincter contraction
At L4-S3 is the pelvic nerve which controls bladder contraction and the Pudendal nerve which controls sphincter contraction

Question 4

How can a spinal cord lesion effect the eye?

Answer 4

sympathetic innervation of the eye runs through the entire cervical spinal cord

Question 5

What are the main clinical signs associated with spinal cord disease?

Answer 5

ataxia, paresis and plegia (combination of 2 or more usually)
spinal hyperaesthesia
bladder dysfunction

Question 6

What is the difference in the location of lesions in the spinal cord and the presentation of ataxia vs paresis/ paraplegia?

Answer 6

Ataxia suggests dorsolateral lesions (white matter of spinal cord)
Paresis/ Paraplegia suggests lesions in the grey matter in the proprioceptive or sensory tracts

Question 7

What does spinal hyperaesthesia suggest about a spinal cord lesion?

Answer 7

Not actually in the cord- spinal cord has no pain receptors- suggests damage to surrounding structures e.g. meninges, intervertebral discs

Question 8

Is Urinary incontinence an upper or lower motor neuron problem?

Answer 8

BOTH- when lesion is in the thoracolumbar spinal cord it causes UMN bladder, increased tone (bladder increases in size and can rupture)
When lesion is localised to S1-S3 of the spinal cord it causes LMN bladder and decreased tone (urine leaks out)

Question 9

What long term affects can UMN bladder cause?

Answer 9

Persistent atonic bladder- bladder stretches so much it struggles to retain to its original shape

Question 10

How do we manage bladder issues in patients with spinal cord disease?

Answer 10

Empty bladder regularly either manually or insert catheter

Question 11

What is Cauda Equina syndrome and what are the two we should know?

Answer 11

used to describe any disease that causes cauda equina dysfunction
NEED TO KNOW- Degenerative lumbosacral Stenosis (DLSS) or Distal Spondylosis

Question 12

What are the clinical signs associated with Cauda Equina syndrome? (5)

Answer 12

Paresis without Ataxia (e.g. not unsteady but reluctant to walk)
Pelvic limb lameness
Pain on hip extension
Decreased tail tone
Urinary incontinence
[no neurological deficits]

Question 13

What does a Schiff Sherrington posture indicate about the location of the lesion?

Answer 13

Indicates its at T3-L3 of the spinal cord

Question 14

Progressive neurological deficits with acute spinal disease occurs in a specific sequence- what is this sequence?

Answer 14

Proprioceptive deficits > Paresis and Ataxia > Plegia > Bladder dysfunction > Tail dysfunction > Pain sensation

Question 15

An intact patella reflex suggests that the lesion is NOT at which parts of the spinal cord?
What is the exception to this rule?

Answer 15

L4-L6
Patella reflex can be physiologically absent in older dogs or after stifle surgery

Question 16

An absent or exaggerated patella suggests what about the location of the spinal lesion?

Answer 16

LMN lesions- reflex will be decreased or absent
UMN lesions- normal or exaggerated.

Question 17

Where would we perform the cutaneous trunci reflex?

Answer 17

Between T2 and L4-L5 spinal cord- absent in neck and lumbosacral regions

Question 18

How does lumbosacral disease cause an absent withdrawal reflex?

HINT- think about what nerve exits the spinal cord here

Answer 18

Sciatic nerve exits spinal cord at L7-S1 where it splits into the peroneal nerve (innervates dorsal part of limb) and the tibial nerve (innervates plantar side of limb)- damage to these parts of the spine can damage the sciatic nerve

Question 19

What clinical signs will be observed in an animal with tibial nerve dysfunction? (3)

Answer 19

Decreased muscle tone
Dropped hock (plantigrade stance)
Overflexion of the Tarsus and loss of hock flexion

Question 20

What are the clinical signs of lower motor neuron lesions?

Answer 20

loss of stimulation- flaccid paralysis
decreased spinal reflexes

Question 21

What are the clinical signs of upper motor neuron lesions?

Answer 21

loss of disinhibiton- excessive stimulation/ excitation
increased muscle tone
increased spinal reflexes