Spinal Cord Disease - Chronic & Progressive

Question 1

what are differentials for chronic, progressive myelopathies

Answer 1

1. IVDD type II
2. degenerative myelopathy
3. diseases of instability (LSS, CSM, AAI)
4. anomalous (CJA, vertebral malformations, constrictive myelopathies)
5. spinal cord neoplasia
6. +/- spondylosis deformans

Question 2

IVDH type II description

Answer 2

disc herniation with annulus fibrosis PROTRUSION into the spinal cord area

Question 3

IVDH type II pathogenesis

Answer 3

fibrous degeneration –> weakening of dorsal annulus –> partial disc protrusion forming dome shaped mass –> compression of spinal cord

Question 4

IVDH type II signalment

Answer 4

breeds: non-chondrodystrophic, large breeds
age: older

Question 5

IVDH type II clinical signs

Answer 5

• hyperesthesia
• paresis
• paralysis
• CP deficits w/ intact reflexes

Question 6

IVDH type II diagnosis

Answer 6

1. radiographs
2. myelography
3. MRI - hypo intensity in spinal canal compressing cord

use history to differentiate from type I

Question 7

IVDH type II treatment

Answer 7

conservative: activity restriction, pain medications

surgical: decompression (hemilaminectomy)

Question 8

degenerative myelopathy (DM)

Answer 8

slow, progressive degeneration of the spinal cord

Question 9

DM signalment

Answer 9

breeds: GSDs, boxers, bay retrievers, corgis, ridgebacks
age: older (~9 years)

Question 10

DM pathogenesis

Answer 10

mutation in SOD I –> amyotrophic lateral sclerosis (ALS)

Question 11

DM clinical signs

Answer 11

• NO hyperesthesia
• progressive PL weakness
• non-ambulatory within 6 months to 1 year of onset

early:
- asymmetric paresis
- general CP ataxia in PLs
- T3-L3 myelopathy signs

late:
- LMN paraplegia to tetraplegia
- TL weakness
- flaccid weakness
- PL muscle atrophy
- dysphagia
- respiratory distress

Question 12

DM diagnosis

Answer 12

diagnosis of exclusion
- no significant findings on MRI, normal CSF
- histopathology is definitive but rarely done

Question 13

DM treatment

Answer 13

none - elect euthanasia once progressed

poor prognosis

Question 14

what are the diseases of instability

Answer 14

• degenerative lumbosacral stenosis (LSS)
• caudal cervical spondylomyelopathy (CSM)
• atlantoaxial instability (AAI)

Question 15

lumbosacral stenosis (LSS)

Answer 15

degenerative narrowing of the intervertebral foramen (similar to IVDH type II)

Question 16

LSS signalment

Answer 16

breed: medium to large
age: middle aged (~7 years)

Question 17

LSS clinical signs

Answer 17

• lumbosacral hyperesthesia
• hunched posture
• muscle atrophy
• CP deficits in pelvic limbs
• reduced flexor and perineal reflexes
• normal to pseudo-hyperreflexia patellar reflex

Question 18

LSS diagnosis

Answer 18

1. radiographs - severe calcifications
2. CT/MRI

Question 19

LSS treatment

Answer 19

conservative: weight loss, activity restriction, corticosteroid injections, NSAIDs
surgical: decompression and stabilization (hemi)

Question 20

caudal cervical spondylomyelopathy (CSM)

Answer 20

lesion in C6-T2 (cervical intumescence) causing narrowing of the spinal canal and spinal cord compression

two types:
- osseous
- disc associated

Question 21

CSM clinical signs

Answer 21

• ambulatory tetraparesis
• thoracic: LMN signs –> choppy thoracic limb gait
• pelvic: UMN signs –> long tract signs (long stride gait)
• CP ataxia
• +/- cervical pain

Question 22

osseous CSM signalment

Answer 22

breed: giant (Great Danes, mastiffs)
age: young (1-2 years)

caused by rapid growth –> osseous proliferation –> stenosis of canal

Question 23

disc associated CSM signalment

Answer 23

breed: large (dobermans)
age: middle to older (>5-6 years)

caused by conformation (spinal instability) –> type II IVDD + ligamentous hypertrophy + joint capsule proliferation

Question 24

CSM diagnosis

Answer 24

1. myelogram
2. MRI/CT

Question 25

CSM treatment

Answer 25

conservative: activity restriction, chest harness, weight loss, pain management surgical: spinal distraction + stabilization OR decompression

Question 26

atlantoaxial instability (AAI)

Answer 26

subluxation of the atlanto-axial joint caused by multiple congenital abnormalities --> instability --> over flexion and dorsal subluxation of axis can be congenital or acquired - most common: dens hypoplasia or aplasia

Question 27

AAI signalment

Answer 27

breed: toy breeds age: young

Question 28

AAI clinical signs

Answer 28

- cervical hyperesthesia - CP ataxia - tetraparesis to plegia

Question 29

AAI diagnosis

Answer 29

1. radiographs 2. CT/MRI

Question 30

AAI treatment

Answer 30

conservative: pain management, corticosteroids, immobilization of C spine, strict rest surgical: dorsal vs ventral stabilization w/ screws or pins and cement

Question 31

cranio-cervical junction anomalies (CJAs)

Answer 31

caudal occipital malformations (COMs) such as chiari like malformations leading to cerebellar dysfunction congenital anomalies leading to overcrowding, compression of cerebellum +/- herniation, kinking of medulla, and CSF flow disruption

Question 32

CJA signalment

Answer 32

breeds: small (CKCS) age: young to middle (~3-6 years)

Question 33

CJA clinical signs

Answer 33

- hyperesthesia in head/neck - cervical localization (paresis to plegia in all 4 limbs) - ataxia - pruritus of face/head - CN VII paralysis/paresis - hypoglossal nerve deficits - syringomyelia

Question 34

syringomyelia

Answer 34

fluid accumulation within the spinal cord parenchyma caused by CJA disrupting the normal CSF flow in the subarachnoid space

Question 35

CJA diagnosis

Answer 35

MRI - visualize attenuation/obliteration of dorsal SAS

Question 36

CJA treatment

Answer 36

conservative: pain management, decrease CSF production/inflammation (corticosteroids), AEDs if seizing surgical: foramen magnum decompression

Question 37

vertebral malformations

Answer 37

errors in embryonic/fetal vertebral center of ossification and/or fusion leading to hemi or butterfly vertebrae can be incidental but some are clinical

Question 38

vertebral malformation diagnosis

Answer 38

most are SUBCLINICAL 1. radiographs 2. CT/MRI (check for compressive lesions if clinical)

Question 39

vertebral malformation treatment

Answer 39

conservative: NSAIDs or steroids surgical: in situ hybridization, decompression

Question 40

constrictive myelopathies

Answer 40

articular process dysplasia congenital anomalies that affect either the caudal articular facet (aplasia, hypoplasia, hyperplasia) leading to secondary constrictive fibrosis of the spinal cord

Question 41

constrictive myelopathy signalment

Answer 41

breed: pugs age: variable; 2-11 years

Question 42

constrictive myelopathy pathogenesis

Answer 42

malformation caudal to T10 --> loss of an articular process in T10 to L3 causing chronic micromotions --> fibrosis and adhesions to spinal cord --> secondary parenchymal changes of the spinal cord and meninges --> constrictive myelopathy

Question 43

constrictive myelopathy clinical signs

Answer 43

- NO hyperesthesia - paraparesis - paraplegia chronic progression of paresis/plegia

Question 44

constrictive myelopathy treatment

Answer 44

conservative vs surgical (decompression + stabilization)

Question 45

spina bifida

Answer 45

congenital bone malformation of unknown etiology causes incomplete closure of caudal neuropore --> neural tube defects --> incomplete closure or fusion of dorsal vertebral arches

Question 46

vertebral and spinal cord primary neoplasia

Answer 46

extradural: most aggressive - osteosarcoma - plasma cell tumor - multiple myeloma intradural-extramedullary: slow growth/progression - meningioma intramedullary: least painful - glioma - ependymoma

Question 47

vertebral and spinal cord secondary neoplasia

Answer 47

lymphoma (extradural) cats - FeLV is risk factor for lymphoma

Question 48

vertebral and spinal cord neoplasia diagnosis and treatment

Answer 48

dx: MRI or CT tx: surgical resection, radiation, chemotherapy