Small animal neurological conditions

Question 1

What can lesions in LMN cause?

Answer 1

loss of reflex, loss of voluntary control, atonia, flaccid paralysis, rapid muscle atrophy

Question 2

What can lesions in UMN cause?

Answer 2

oss of “calming effect”; loss of voluntary control; reflex intact and may be hyperactive, hypertonia, spastic paralysis.

Question 3

What are the main causes of spinal cord dysfunction?

Answer 3

Compression

Contusion

Laceration

Ischaemia

Inflammation

Question 4

From grade 1-5, what are the clinical signs for each grading?

Answer 4

1 - spinal pain

2 - Paresis (ambulatory)

3 - Non-ambulatory paresis

4 - Paralysis

5 - Paralysis with absence of pain perception

Question 5

How could you treat spinal cord lesions?

Answer 5

Surgical decompression

Appropriate treatment for infection / inflammation

Physical rehabilitation

Question 6

Define tetraparesis

Answer 6

reduced voluntary motor function in all 4 limbs

Question 7

Define tetraplegia

Answer 7

total absence of voluntary motor function in all 4 limbs.

Question 8

What clinical signs will you see in cervical spondylomyelopathy?

Answer 8

Progressive ataxia

Tetraparesis

Neck pain

Question 9

What can cause cervical spondylomyelopathy?

Answer 9

Progressive spinal cor compression

Can be result of congenital stenosis and degenerative changes in the vertebral column

Question 10

How would you treat cervical spondylomyelopathy?

Answer 10

Surgery for patients with neurological deficits (to decompress/stabilise) the cervical spine.

Medical includes treatment of pain, restriction of unmonitored activity and controlled exercise/physical therapy.

Question 11

Describe intervertebral discs

Answer 11

Intervertebral discs are fibrocartilagenous cushions between the vertebra

Outer rim (annulus fibrosus) and inner ‘jelly like’ centre (nucleus pulposus).

Allow movement, support and act as shock absorbers

Question 12

Describe acute cervical disc disease (Hansen type I)

Answer 12

Hansen Type I; chondroid degeneration of nucleus pulposus; either bulges into spinal canal – progressive disease

or

Dorsal extrusion through annulus fibrosus - acute spinal trauma

Question 13

What breeds is acute cervical disc disease common in (Hansen type I)?

Answer 13

Shih tzu

Dachsunds

Pekingese

Beagles

Question 14

What are the clinical signs of acute cervical disc disease (Hansen type I)?

Answer 14

severe neck pain; head held down, rigid neck, back arched (transfer weight to pelvic limbs)

Question 15

What neurological signs may be seen in acute cervical disc disease (Hansen type I)?

Answer 15

tetra/hemi paresis/plegia, ataxia, proprioceptive and postural deficits.

Question 16

Describe the pathogenesis of acute cervical disc disease (Hansen type I)

Answer 16

nucleus pulposus (gelatinous) premature aging in chondrodysplastic breeds

Hansen Type I disease

C2-C3 most commonly affected in small breeds

C6-C7 in large breeds

Question 17

How would you diagnose acute cervical disc disease (Hansen type I)?

Answer 17

Clinical signs

Diagnostic imaging

Question 18

Describe medical management of acute cervical disc disease (Hansen type I)

Answer 18

Pain relief and strict cage rest (4 weeks). Aim of cage rest is to allow annulus fibrosus to heal.

If neck pain ↓ gradual reintroduction to exercise

If pain persists or returns or neurological deficits are present requires surgery.

Question 19

Describe surgical treatment of acute cervical disc disease (Hansen type I)

Answer 19

Ventral slot (to remove extruded material) with fenestration of adjacent discs (opening into annulus)

Post surgery; pain relief & confinement for 4 weeks (2 weeks cage rest; 2 weeks progressive return to exercise)

Physiotherapy

Question 20

Describe acute cervical disc disease (Hansen type II)

Answer 20

Fibrinoid degeneration of nucleus pulposus and protrusion of annulus fibrosus (hypertrophy) into spinal canal

More common

Question 21

What animals are more prone to acute cervical disc disease? (Hansen type II)

Answer 21

More common in older, non-chondrodystrophic dogs

Question 22

What are the clinical signs of acute cervical disc disease? (Hansen type II)

Answer 22

chronic, slowly progressive signs. Spinal pain may or may not be evident

Neurological deficits often less severe than with type 1 disease.

Question 23

Describe treatment for acute cervical disc disease (Hansen type II)

Answer 23

conservative in milder cases, surgery indicated when neurological deficits are more severe.

Question 24

Describe acute cervical disc disease (Hansen type III)

Answer 24

Explosion of the nucleus pulposus from a sudden tear in the annulus typically associated with heavy exercise or trauma.

Aka High velocity low volume extrusion

Question 25

Describe tretraparesis caused by atlantoaxial instability

Answer 25

Instability of atlas and axis junction Congenital form – onset of signs most commonly seen in dogs less than 2 years age Trauma

Question 26

What are the signs of Atlantoaxial Instability?

Answer 26

neck pain (waxing and waning), ataxia, tetraparesis, postural and proprioceptive deficits normal or increased myotactic reflexes/ muscle tone

Question 27

How would you treat Atlantoaxial Instability?

Answer 27

Medical; for those cases with mild signs External splint for 6 weeks – to stabilise and allow ligaments to heal Surgical management; required if neurological deficits present Stabilisation of atlanto-axial junction – screws, pins etc.

Question 28

What are the two common causes of traumatic spinal injury?

Answer 28

fractures and luxations.

Question 29

Describe medical and surgical management of a traumatic spinal injury

Answer 29

Medical management – splints / cage rest Surgical management – spinal stabilization

Question 30

Describe tetraparesis caused by Fibrocartilagenous embolism (FCE)

Answer 30

Signalment; Peracute onset of non-painful neurological deficits Usually large, young non-chondroplastic breeds – commonly at lumbosacral intumescence Also smaller breeds represented; Shetland Sheepdog, Miniature Schnauzer, Yorkshire Terrier – usually C6-T2

Question 31

What is the pathogenesis of FCE?

Answer 31

fibrocartilagenous embolism from spinal structure – spinal blood vessel blocked– ischaemic necrosis of spinal cord grey matter.

Question 32

State the clinical signs of FCE

Answer 32

often lateralised – hemiparesis May get Horner’s Syndrome (sympathetic system affected) and vasodilation on the affected side (up to 10°C warmer)

Question 33

What are two bacterial causes of tetraparesis?

Answer 33

Tetanus (Clostridium tetani) Botulism (Clostridium botlulinum)

Question 34

Describe paraparesis

Answer 34

Most common cause is disease of the thoracolumbar spine. Clinical signs dependent on where cord is affected; T3-L3 or L4-S3.

Question 35

What complications can occur from an acute severe spinal cord injury?

Answer 35

Neurogenic shock Spinal shock

Question 36

Describe neurogenic shock

Answer 36

Sympathetic ns dysfunction (with parasympathetic function) – decreased blood pressure, heart rate – may lead to ischaemia – kidney failure Present in humans; rarely clinically in dogs/cats

Question 37

Describe spinal shock

Answer 37

Flaccidity caudal to the lesion – decreased spinal reflexes

Question 38

Describe paraparesis caused by degenerative myelopathy

Answer 38

Insidious, progressive ataxia and paresis of pelvic limbs progressing to paraplegia Initially recognised in GSD, but other breeds as well Average age of onset – 9 years

Question 39

What are the signs of degenerative myelopathy?

Answer 39

early; general porprioceptive ataxia and mild spastic paresis of pelvic limbs; worn nails on pelvic limbs most large breed dogs progress to non-ambulatory within 6 – 9 months Late stage – LMN signs in pelvic limbs and UMN signs in thoracic limbs; eventually tetraplegia Severe muscle atrophy

Question 40

What are the treatment options for degenerative myelopathy?

Answer 40

non-specific. Poor prognosis. Physiotherapy and hydrotherapy may help manage the condition (maintenance of muscle strength) and associated with longer survival.

Question 41

Describe paraparesis caused by Type I Hansen disc disease

Answer 41

Back pain, kyphosis, reluctance to walk Paraplegia, reduction in nociceptor responses In small breeds most commonly at T12-T13; in Large Breeds mainly L1-L2

Question 42

Describe treatment for Type I Hansen Disc disease (paraparesis)

Answer 42

Medical management; for mild spinal pain -as per cervical lesions Surgical management; Spinal cord decompression Dorsal laminectomy Hemilaminectomy (lateral approach) + fenestration Post surgical management as per cervical lesions

Question 43

Describe monoparesis

Answer 43

Monoparesis / plegia? Nerve Root Signature = pain manifested as lameness due to nerve root irritation / compression

Question 44

What nerves can cause monoparesis?

Answer 44

Brachial plexus- network of nerves innervating the forelimb (arise from spinal nerves C6-T2). Lumbosacral plexus- network of nerves innervating the hindlimb (arise from L4-S3 in the spinal cord).

Question 45

Define neuropraxia

Answer 45

interruption of nerve conduction without physical disruption of the axon.

Question 46

Define axonotemesis

Answer 46

physical interruption of the axon.

Question 47

Define neurotemesis

Answer 47

complete severance of the nerve- most severe type of injury.

Question 48

Describe foraminal stenosis

Answer 48

Narrowing of foramen where nerve roots exit LMN signs localised to one or more nerve roots Nerve root signature; pain on manipulation or palpation of affected limb Lameness of affected limb – may avoid weight-bearing May be constant, intermittent or exacerbated by exercise

Question 49

Describe treatment for foraminal stenosis

Answer 49

Medical management; NSAIDs and pain relief (but often signs return) Surgical; dorsal laminectomy and/or foraminotomy

Question 50

Describe brachial plexus avulsion

Answer 50

RTAs, fall from height – adduction and caudal displacement of thoracic limb Acute onset; either Cranial avulsion (C6-C8 nerve roots) Caudal avulsion (C8-T2) Complete avulsion (C6-T2)

Question 51

What are the clinical signs of brachial plexus avulsion?

Answer 51

Cranial is rare and few clinical signs; Atrophy of supra/infraspinatus Loss of shoulder flexion/extension; loss of elbow flexion. Can bear weight. Caudal and Complete more common and more severe signs; Loss of elbow extension (triceps brachii) – no weight-bearing and drags limb with carpus knuckled. Severe neurogenic atrophy Caudal alone – flexor muscles work therefore tends to carry limb

Question 52

Describe treatment for brachial plexus avulsion

Answer 52

Non-specific – physiotherapy and keep limb clean and protected Cranial avulsions can bear weight and have a good prognosis Complete/caudal avulsions – poorer prognosis; depends on severity of nerve damage. May require limb amputation