Principles of Spinal Disease

Question 1

The most common spinal problems we see are related to….

Answer 1

• The intervertebral disc

Question 2

Difference between ataxia and paresis

Answer 2

Ataxia: related to something sensory

paresis: something motor

Question 3

Ataxia

Answer 3

loss of coordination

• sensory dysfunction
• proprioceptive ataxia in spinal disease
• Animal walks like it is a bit drunk and doesn’t know where to place its feet

Question 4

Paresis

Answer 4

weakness

• motor dysfunction
• decreased muscle tone, inability to initiate movement, shorter stride
• different to plegia as they still have some movement! - decreased voluntary movement, motor phenomenon, can be UMN or LMN in nature
• can further divide this into non-ambulatory and ambulatory paresis

Question 5

Some Disorders where you can expect there to be spinal pain present (3)

why?

Answer 5

1. intervertebral disc disease
2. something affecting the nerve roots
3. meningitis

• structures surrounding the spinal cord have loads of pain receptors
• where as the spinal cord itself does not and so lesions isolated to the spinal cord alone are generally non-painful (ex: fibrocartilagenous embolism)

Question 6

Where does the spinal cord terminate in most dogs?

Answer 6

L6

• the lumbosacral junction is about S7-L1

Question 7

the four functional spinal cord segments

Answer 7

1. C1 - C5
2. C6-T2
3. T3-L3
4. L4- S3

how we localize the lesions for spinal disease

• really helps with differential Dx’s for spinal cord problems as many will actually have a preference for certain segments

Question 8

Intrinsic Myelopathies

Answer 8

• lesion within the spinal cord itself
• tumor, contusion in the spinal cord for example

Question 9

Extrinsic Myelopathy

Answer 9

• primary condition outside the spinal cord that is causing spinal cord disease
• intervertebral disc disease that is pushing against the spinal cord for example

Question 10

Plegia

Answer 10

• Abscence (complete loss) of voluntary movement
• completely paralysed
• can be further divided:

1. mono- : one limb affected
2. para-: both pelvic limbs affected
3. hemi-: ipsilateral thoracic and pelvic limb affected
4. tetra-: all four limbs affected

Question 11

Incontinence

Answer 11

• Inability to urinate voluntarily
  1. inability to fill properly
  2. inability to empty bladder properly (more common)
• can be UMN or LMN

Question 12

One exception where you can predict the prognosis of spinal disease…

Answer 12

Acute Spinal Disease

Question 13

5/8 parts of the neuro exam that are important in investigating spinal disease

Answer 13

• OBSERVING THEM IS REALLY IMPORTANT
• you need to dedicate enough time for this

Question 14

What could be indicated by a dog with paraparesis, but not ataxic

(in terms of gait)

Answer 14

• lumbosacral disease
• might see short stilted pelvic limb gait with a flaccid tail

Question 15

If an animal has proprioceptive deficits…

Answer 15

• you can be almost certain that it has a form of neurological disease
• but this can be due to a variety of components –> brain disease, spinal cord disease

Question 16

When an animal with acute spinal disease becomes progressively paralysed, it goes in a very specific order

• What is that order?*
• What disappears last in the sequence?*
• Which Disappears first?*

Answer 16

-so if you see an animal with abnormal gait that you suspect to have acute spinal cord disease –> they SHOULD have proprioceptive deficits as well as it precedes it

Question 17

Wha tis one of the most difficult diseases to differentiate from spinal disease??

Answer 17

• bilateral partial cruciate disease
• may present with some ataxia and plegia that indicate spinal disease, but if the proprioception is still there (while being supported) then likely not acute spinal cord disease with progressive signs

Question 18

what major nerve may be affected if the patellar reflex is decreased or absent?

Answer 18

Femoral n.

Question 19

what are the 3 types of spinal reflexes?

Answer 19

• patella reflex
• withdrawal reflex
• cutaneous trunci

only help you further localize lesions!

-these are reflexes that travel up to the spinal cord and back down

Question 20

What really can an absent patellar reflex tell you?

Answer 20

• Only thing you know from an absent patellar reflex is that IF the animal has spinal disease, it will be localized in that area (L4-S3)
• Forms the basis for the localization of spinal cord problems into spinal cord segments
• If the reflex is absent in the thoracic limb, we localize it to the C6-T2 segment

Question 21

what would the “engine” or “disconnected” gait in a patient be suggestive of?

Answer 21

Suggestive of caudal cervical problem localized to the C6-T2 spinal cord segments

• Thoracic limbs –> short and stilted
• Pelvic limbs –> wide based ataxia

Question 22

where is the spinal cord lesion most likely when an animal has incontinence where the bladder leaks?

cannot hold urine

Answer 22

L4-S3 segment

-likely to also have a flaccid tail with this lesion

Question 23

There are only 3 peracute conditions that can really occur with acute spinal disease:

Answer 23

1. Fractured luxation
2. Fibrocartilagenous embolism
3. Acute non compressive nucleus pulposus extrusion

Question 24

Lateralized means…

Answer 24

• one side is OBVIOUSLY worse than the other. To where the client knows as well

Question 25

One leg still has quite good movement, while the other is just dragging

-this is a lateralized lesion

• this is an essential difference to note for your differentials!
• one condition can really cause this……what is it?

Answer 25

• Acute noncompressive nucleus proposus extrusion

Question 26

High velocity low volume disc and _____ are the same condition

Answer 26

• Acute non compressive nucleus proposus extrusion

Question 27

Most common spinal diseases in dogs

(6)

Answer 27

Question 28

Most common spinal diseases seen in cats

(6)

Answer 28

Question 29

Most common neurological problem seen in equine practice..

Answer 29

myelopathies

• muscle disease also being very important

Question 30

Where do the axons conveying proprioception information run in the SC?

Answer 30

• These axons that convey proprioceptive information travel primarily in the dorsal funiculus of the white matter and the dorso lateral aspects of the white matter of the spinal cord
• dorsal/dorsal lateral aspects of the white matter of the SC

Question 31

What is the main clinical sign associated with defective proprioception?

Answer 31

• ataxia

Question 32

How is it that a horse can exhibit weakness with a neck lesion?

Answer 32

• It affects the UMN’s and therefore it’s control of muscle contraction is lost
• If you don’t control contraction properly then it means the timing of muscle contraction is lost slightly
• The timing of contraction is lost or the amount of muscle contraction is lost –> so they look weak!

Question 33

what effects can you see in animals with a neck lesion?

(horses, dogs, cats alike)

Answer 33

1. defective proprioception –> ataxia
2. defective motor function –> weakness

Question 34

Differential Dx for Equine Spinal Ataxia

(Proprioceptive dysfunction associated with spinal cord disease)

Answer 34

Question 35

If you see an arabian foal that is somewhat ataxic and stiff in the neck…

Answer 35

• quite likely to be Occipitoatlanto-axial malformation (OAAM)
• a congenital malformation in foals (particularly Arabians)

Question 36

ankylosis

Answer 36

• abnormal stiffening and immobility of a joint due to fusion of the bones
• sometimes with trauma, we can see ankylosis and fracture over time

Question 37

get a male, TB horse, young (2-3 years of age), presenting with signs of ataxia and paresis… high likelihood that

Answer 37

that this horse is going to be a “wobbler” - Spinal Cord Compression

• clinical and neuro exam are essential!