L16: Ataxia and paresis: principles of spinal and lumbosacral disease

Label this

What are some anatomical considerations of the spine

• Spinal cord and vertebral column do not have the same length

• Vertebral column is longer than spinal cord

• There is no spinal cord present at the lumbosacral junction

• the lumbosacral vertebral canal is occupied by the caudal equina

When does the spinal cord end in dogs and cats

Dogs: ~L6

Cats: ~L7

How many segments are in the spinal cord

four functional segments based on whether it contains functional LMN

What are the 4 functional segments of the spinal cord

• C1-C5

• C6-T2

• T3-L3

• L3-S3

Does sensory and motor ascend, descend or both

Ascending is sensory

Descending is motor information

What tends to characterise spinal cord disorders

combination of sensory and motor dysfunction

What occurs in the dorsal and lateral funiculi and what happens if its damaged

sensory and proprioceptive tracts

ataxia

What occurs in the ventral and lateral funiculi and what happens if its damaged

Motor or UMN tracts

UMN paresis

what occurs in the LMN cell bodies

Ventral horn grey matter

LMN paresis

What dysfunction also occurs with spinal cord dysfunction

Bladder

Hypogastric nerve

• Bladder relaxation

• integral sphincter contraction

Pelvic nerve

• Bladder contraction

Pudendal nerve

• External sphincter contraction

What type of innervation of the eye runs through how much of the spinal cord

• Sympathetic innervation of the eye runs through entire cervical spinal cord

What are the typical clinical signs for spinal cord disease

• Ataxia, paresis, plegia

• Spinal hyperaesthesia

• Bladder dysfunction

• Gait abnormality typically characterized by COMBINATION of ataxia and paresis:

  • Proprioceptive or spinal ataxia

Define ataxia

• A- (G) without

• -taxis (G) order

• Synonym = Incoordination

• Sensory phenomenon

• Spinal or proprioceptive ataxia in spinal disease

Define paresis

• Decreased voluntary movement

• Motor phenomenon

• ambulatory and non-ambulatory paresis

• can be UMN or LMN in nature

Define plegia

Absence (complete loss) of voluntary movement

mono, hemi, para, tetra

TRUE OR FALSE

the spinal cord has no pain receptors

True

What structures around the spinal cord have an abundance of pain receptors

• Meninges

• intervertebral disc

• periosteum

TRUE OR FALSE

Intrinsic spinal disorders are really painful (degenerative myoelopathy)

will not be painful

What sign can help in finding the most likely differential diagnosis

• Spinal hyperaesthesia

Define urinary/fecal continence

Ability to fill and empty bladder/intestines voluntarily d

define urinary/faecal incontinence

loss of ability to fill and empty bladder/intensifies voluntarily

Can be UMN or LMN

What happens to urinary incontinence when the lesion is located in the thoracolumbar spinal cord segments

• UMN bladder

• increased tone detrusor muscle

• increased tone urethral musculature

What happens to urinary incontinence when the lesion is located in the S1-S3 spinal cord segments

• LMN bladder

• decreased tone detrusor muscle

• decreased tone urethral musculature

What does an upper motor neuron bladder feel like on palpation/presentation

• Large an full bladder, feels firm and turgid

• resistance to manual expression

• inconsistent leakage from overly full bladder

  • overflow incontinence

  • risk of bladder wall damage

  • Persistent atonic bladder wall

    • caused by over stretching

What does an lower motor neuron bladder feel like on palpation/presentation

• Decreased bladder tone, flaccid bladder

• easily expressed

• can leak urine spontaneously

  • skin irritation (urine scald)

  • Persistent UTI

What are the associated issues with urine retention

• UMN and LMN bladder result in both urine retention

• Increases UTI risk

• Occur commonly in non- ambulatory spinal patients

what does emptying the bladder for non ambulatory spinal patients prevent

• Development of UTI

• damage bladder wall by overstretching

• overstretching can result in persistent bladder atony

• urine leaking resulting in urine scald

What are some methods for bladder emptying

• Manual bladder expression

• repeated aseptic catheterisation

• indwelling foley catheter with closed collection system

What is cauda equina compression associated with

• Associated with clinical signs than dogs with spinal disorders

• different pathophysiology and principles of regeneration

What are the common signs of cauda equina syndrome

• Often vague, unspecific clinical signs

• Paresis WITHOUT ataxia

• Pelvic limb lameness

• Spinal hyperaesthesia can be present

• Often pain on extension hips

• Can be painful on dorsal extension tail

• Decreased tail tone

• Urinary/faecal incontinence

• Often no neurological deficits

What posture is seen on neuro exam of spinal and lumbosacral exam

• Crouched kyphosis

• low head carriage

• schiff-sherrington

What is the schiff sherrington posture

• Acute T3-L3 spinal cord injuries

• Borders cells (L1-L7 spinal cord segments)

  • Project to cervical intumescence

  • Provide inhibition to extensor muscles thoracic limbs. “Disinhibtion”

  • Paraplegia with increased extensor tone thoracic limbs

• Differentiation from cervical lesion:

  • Thoracic limbs neurologically normal

• Indication of localisation, NOT prognosis

What is gait like in a neuro exam of spinal and lumbosacral exam

• Often combination of ataxia and paresis in animals with spinal cord disease

• Paresis or lameness in animals with lumbosacral disease

• What is proprioception like in a neuro exam of spinal and lumbosacral area

• reliable indicator for presence of neurological disease

• Proprioceptive deficits can be seen in animals with spinal, brainstem and forebrain diseases

what is the sequence of progressive neurological deficits with acute spinal disease

1. Proprioceptive deficits (occur before gait)

2. Paresis and ataxia

3. plegia

4. bladder dysfunction

5. tail dysfunction

6. pain sensation/nocioception

What is spinal reflexes like in a neuro exam of spinal and lumbosacral exam

• Withdrawal reflex and patella reflexes

• Cutaneus trunci reflex

• Differentiation UMN and LMN signs

• Spinal cord and neuromuscular (neuropathy)

• Patella reflex can be “physiologically” absent in:

  • Older dogs (symmetrical)

  • After stifle surgery

• Withdrawal reflex and nociception are not the same

What does an absent of decreased spinal reflex suggest

Lesion is localised in the reflex arc

• does not give prognostic information

• differentiation UMN and LMN signs

what is the cutaneous trunci reflex

• ‘Panniculus reflex’

• Pinching the skin over the dorsum and observing a muscle twitch

• Between T2 and L4-L5

  • (absent in neck and lumbosacral region)

• Lesion is located approximately two

• vertebrae proximal of ‘cut-off ‘:

  • Unreliable to predict specific localisation

  • Confirmation of thoracolumbar spinal injury

IF neurological deficits are observed in animals with lumbosacral disease, this is often characterised by what nerve dysfunction

• Sciatic nerve

How does lumbosacral disease cause nerve dysfunction and where

• Exits the L7-S1 intervertebral foramen as the sciatic nerve

• Splits more distally into

  • Peroneal nerve, which innervates dorsal part distal limb

  • Tibial nerve, which innervates plantar side distal limb

• Tibial nerve dysfunction most obvious in dogs with lumbosacral disease

What is seen in tibial nerve dysfunction

• Dropped hock

  • Plantigrade stance in cats

• Decreased tarsal innervation can result in ‘characteristic’ gait with overflexion of the tarsus

• Decreased muscle tone distal from tarsus

• Loss of hock flexion during withdrawal

What is palpation like in a neuro exam of spinal and lumbosacral exam

• Keep this part for the end

  • Sometimes against intuition

• start with gentle palpation

What is nocioception like in a neuro exam of spinal and lumbosacral exam

• Provide painful stimulus

• pinching nailbed with

  • Fingers: superficial pain perception

  • Artery forceps: deep pain perception

• Look for conscious reaction

  • Vocalisation

  • trying to flee

  • trying to bite

• only necessary to test in

  • plegic animals

  • differentiation stupor from coma

  • Suspicion of sensory neuropathy

    • extremely are

• if necessary, don’t test it

What is the clinical presentation with clinical signs and abnormalities

Clinical signs

• No gait abnormalities, but spina hyperaesthesia

• Combination of ataxia and paresis

• paresis → plegia

• bladder dysfunction

• urine retention or leakage

Abnormalities

• Proprioceptive deficits

• intact or abnormal spinal reflexes

• spinal hyperaesthesia present or absent

• pain sensation can be decreased in plegic animals

What syndrome can be seen in animals with cervical spinal disease

Horner’s

What are the clinical signs of hooch

• Ipsilateral miosis

• enipthalmos

• third eyelid protrusion

• ptosis upper eyelid

• normal vision

What is the concept of UMN and LMN lesions

UMN= situated CNS and controls LMN

LMN- final pathway between CNS and target organ

What clinical signs do you see on a LMN lesions

• Loss of stimulation or excitation

• decreased muscle tone

  • Flaccid paralysis

• Decreased spinal reflexes

What clinical signs do you see on a UMN lesion

• Loss of inhibition= disinhibition

• Excessive stimulation or excitation

• increased muscle tone- spastic paresis

• increased spinal reflexes

what is the theory behind how LMN and UMN lesions differ

• Spinal cord lesion causes LMN signs at site of injury and UMN signs caudal from site of injury

• in clinical practice: LMN signs only visible if lesion localised at the cervicothoracic or lumbosacral intumescence

• basis for localising spinal cord lesions to specific spinal cord segments

What questions do you ask to localise a lesion

What are the ways in diagnosing/ getting differentials

• DAMNIT V

• 5 finger rule

How does the 5 finger rule work

Start with localisation:

Onset:

• Difference between acute and per-acute!!

• Chronic

Progression:

• Not many disorders improve spontaneously

• Don’t get fouled by first 12-24 hours

Symmetry:

• Not many disorders are truly asymmetrical

Pain:

• Presence of pain excludes several conditions

• Not all painful conditions are necessarily associated with pain

Signalment:

• Species → cats vs dogs

• Breed: not every Dachshund has IVDD though

• Age

What are the common differentials for dogs

Type I intervertebral disc disease – 29.8% § Intervertebral disc extrusion (IVDE)

Type II intervertebral disc disease – 19% § Intervertebral disc protrusion (IVDP)

Ischaemic myelopathy – 9.6% • Neoplasia - 8.8%

Syringomyelia – 5.8%

Immune mediated myelitis – 5.8%

Acute non-compressive nucleus pulposus extrusion § high-velocity low-volume disc extrusion – 4.8%

Degenerative lumbosacral stenosis – 2.8% § Most common cause of lumbosacral disease

Cervical spondylomyelopathy – 2.0%

Steroid responsive meningitis arteritis – 1.8%

Spinal arachnoid diverticulum – 1.8%

What are the common differentials for cats

Neoplasia other than lymphoma - 19.9%

Intervertebral disc disease – 19% § Type I and Type II

Vertebral fracture and luxation – 15.4%

Ischaemic myelopathy – 10%

Feline infectious peritonitis virus - 8.1% § Young cats!

Spinal lymphoma – 7.2% § Young cats!

Thoracic vertebral canal stenosis – 5.0% § (no information in textbooks)

Acute non-compressive nucleus pulposus extrusion – 5.0%

Traumatic spinal cord contusion – 3.6%

Spinal arachnoid diverticulum - 3.2%