Neuro-chronic progressive spinal cord disfunction Flashcards
What are 8 disorders that cause chronic progressive spinal cord disfunction?
- neoplasia
- degenerative myelopathy
- type 2 disk protrusion
- cauda equina syndrome
- cervical spondylomyelopathy (wobbler)
- intraspinal articular cysts
- arachnoid cysts
- syringomyelia/hydromelia
What animals are most often affected by spinal tumors?
large breed dogs
middle age to oldder dogs (5-6 years)
What are two spinal tumors that don’t necessarily affect older dogs?
lymphoma (any age)
neuroepitheliuma T10-L1 in young dogs
Spinal lymphoma is most common in what cats?
young (4yr) adult FeLV positive cats
What are clinical features of spinal tumors?
- related to location
- pain may be prominent with nerve root tumors, tumors involving meninges, aggressive tumors involving bone
NOT tumors of spinal cord usually
How is neoplasia diagnosed?
signalment, history, physical exam, screening blood tests, plain radiographs
What does definitive diagnosis of neoplasia usually require?
CSF analysis
diagnostic imaging
histopathologic evaluation
Whenever a neoplasm is considered as a ddx, what should be done?
a complete physical examination and systemic evaluation to look for sites of primary tumor
- fundic exam
- palpate lymph nodes
- rectal
- thoracic and abdominal radiographs
- U/S of spleen, liver, heart
- maybe lymph node aspiration, cbc, bone marrow smears
What are further diagnostics of the spinal region that may help with diagnosis of neoplasia?
- survey radiographs of affected region
- CSF analysis—tumors rarely exfoliate though
- myelography–can characterize location
- advanced imaging for more precise localization
How are spinal tumors treated?
1.surgical decompression attempts at complete tumor excision in well encapsulated tumors
feline meningiomas have good prognosis, intramedullary tumors have poor prognosis
2. chemotherapy, radiation therapy
3. corticoteroids–temporary improvement
What is degenerative myelopathy?
a degenerative disorder of the spinal cord white mater characterized by widespread myelin and axon loss
Who does degenerative myelopathy occur most frequently in?
aging
German shepherd
cardigan and pembroke welge corgies
5-14yrs
What regions are most severely affected by degenerative myelopathy?
thoracic and thoracolumbar spinal cord
What is the etiology of degenerative myelopathy?
inheritance of a genetic mutation similar to Lou Gehrigs
Why is testing for the genetic mutation involved with degenerative myelopathy not sufficient to diagnose degenerative myelopathy?
because the animal may have the mutation without having the dhsease
What are the clinical signs of degenerative myelopathy?
- slowly progressive (mo-yr)
- UMN paraparesis and ataxia of rear limbs
localization to T3-L3
How is degenerative myelopathy diagnosed?
- signalment
- slowly progressive spinal ataxia, UMN weakness in rear limbs
- systemically normal
- no spinal pain
What are differential diagnoses for degenerative myelopathy?
- neoplasia
- type II disk dz
- enlarged articular facets compressing spinal cord
- musculoskeletal dz affecting rear legs (careful neuro exam)
=diagnosis of exclusion!!
What are the results of radiography, CSF analysis, myelography/advanced imaging with degenerative myelopathy?
- normal spinal radiographs
- cytologically normal CSF
- normal myelogram or MRI
What is the treatment for degenerative myelopathy?
no treatment
exercise may be helpful
aminocaproic acid EACA
What is type II intervertebral disk disease
Fibroid degeneration of intervertebral disk, partial rupture of disk annulus and prolapse of a small amount of disk nucleus into annulus firosus
In what does is type II intervertebral disk disease seen most often?
large breed dogs German Shepherd Lab Doberman (occasionally small)
what are clinical features of type II intervertebral disk disease?
Depends on location
Thoracic: UMN rear limbs
Cervical: UMN all limbs, pelvic limbs more, maybe pain
lumbosacral: cauda equina syndrome
How is type II intervertebral disk disease diagnosed?
- slow progressive signs of spinal cord disfunction
- radiographs–may be normal, not good at localizing site
- CT/MRI important
What are radiographic signs of type II intervertebral disk disease?
- disk space narrowing
- osteophyte prouction
- end plate sclerosis
What is treatment for type II intervertebral disk disease?
- low doses of corticosteroids (short neuro improvement, not a cure)
Surgical: - ventral decompression/hemilaminactomy
What is the goal of therapy for type II intervertebral disk dz?
to stabilize the animals neurogic status (unlikely to see full recovery!)
What are intraspinal synovial cysts?
Cysts arising from the joint capsule of spinal facetal joints affected by degenerative change
Can compress spinal cord or nere roots
What dogs are most often affected by intraspinal synovial cysts?
young large and giant breed dogs
How is intraspinal synovial cysts diagnosed?
- signs
- signalment
- evidence of DJD at articular facets at area of interest
- MRI required!
What is treatment for intaspinal synovial cysts?
- decompression
- cyst drainage
- stabilization
What are arachnoid cysts?
accumulation of CSF in structures within the subarachnoid space
Who gets arachnoid cysts?
young dogs
What is the treatment for arachnoid cysts?
exploration and marsupialization of the cyst
What is cauda equinia syndrome?
Compression of the nerevs of the cauda equina
What can cause compression of the nerves of the cauda equina?
- disk protrusion
- tumor
- diskospondylitis
- vertebral or sacral osteochondrosis
- congenital bony malformation
- progressive proliferation of tissues in lumbosacral region (degenerative lumbosarcal stenosis)
What is the most common cause of cauda equina compression in older large breed dogs?
- Acquired type II disk prolapse with progressive lumbosacral stenosis caused by bone remodelling and soft tissue proliferation
What dogs are most often affected by cauda equina syndrome?
- german shepherd
- lab
- belgian malinois
most often males over 5
What are clinical signs of cauda equina syndrome?
- slow to rise from prone
- reluctant to run, sit up, jump, climb stairs
- rear limb lameness and weakness worsen with exercise
- reluctant to raise or wag tail
- may get hyperesthesia or paresthesia of perineum
Why does rear limb lameness and weakness worsen with exercise with cauda equina syndrome?
neurogenic intermittent claudication
The blood vessels accompnaying the spinal nerve roots in the intervertebral foramen dilate and further compress the nerve roots
What is found on physical exam with cauda equina syndrome?
- pain elicited by deep palpation of dorsal sacrum or dorsiflexion of tail or hyperextension of lumbosacral region
- may be difficult to distinguish from other diseases if no neuro deficits
- rear limb weakness, atrophy of muscles of caudal thigh and distal limb (sciatic) and deccrease in limb flexion, esp hock during withdrawal reflex if there are neurodeficits
- proprioception normal, not ataxic
- urinary dysfunction only if VERY severe
How is cauda equina syndrome diagnosed?
- clinical findings
- radiographs to rule out causes of cauda equina compression (diskospondylitis, lytic vertebral neoplasia, fracture/luxation) and find predisposing factors for degenerative stenosis (osteocondrosis, vertebral malformations)
What are radiographic changes commonly seen with cauda equina syndrome due to stenosis?
- end plate sclerosis
- spondylosis of ventral and lateral margins of L7 and S1 end plates
- proliferative changes on L7-S1 facets
- narrowing or collapse of L7-S1 intervertebral disk space
Why must you have caution when interpretinng radiographs of the lumbosacral region in a suspected cauda equina dog?
many of the same abnormalities are common in clinically normal dogs and dogs with clinically significant compression may have normal radiographs
What is the most sensitive, accurate and noninvasive means of evaluating the lumbosarcal region and visualizing all components potentially involved in cauda equina compression?
MRI
What is the treatment for cauda equina syndrome if there are no neuro defects?
- restrict exercise
- analgesics/anti-inflammatories
a. NSAIDs, tramadol, gabapentin
How is cauda equina syndrome surgically treated?
lumbosarcal dorsal laminectomy, excision of compressing tissues and foraminotomy of L7-S1
distraction-fusion can be used to improve stability
then strict confinement
What is the prognosis for dogs treated surgically for cauda equina syndrome?
very good for dogs with lameness and mild neurologic defects
good for mild to moderate neuro defects (70-80%)
but later recurrence may be high
dogs with severe LMN defects may have permanent deficits
What is cervical vertebral instability? (wobbler’s)
Caudal cervical spinal cord and nerve root compression in large breed dogs secondary to developmental malformations, cervical instability or instability associated changes in vertebral canal
What may cause verebral canal narrowing with cervical vertebral instability (wobblers)
- malformed vertebral laminae
- hypertrophy of ligamentum flaum
- articular facet enlargement
- periarticular soft tissue hypertrophy
(or combination)
can also lead to disk herniation
What animals are most commonly affected by cervical vertebral instability? (wobbler’s)
Great Danes
Doberman Pinschers
(can be other breeds)
age presentation varies
What are the most common abnormalities causing wobbler’s in Danes?
stenosis of cranial aspect of cervical vertebrae and articular facet deformities
What is the most common cause of wobbler’s in dobermans?
vertebral column instability with spinal cord compression by secondary soft tissue hypertrophy, disk, with or without cervical vertebral malformation
occurs in middle-age, older dobermans
What are the clinical features of cervical vertebral instability?
- slowly progressive paresis and incoordinated wobbling gait, esp pelvic limbs
- traumatic eposidoe may result in acute exacerbation
- braod based stance in rear
Why are rear limbs more severely affected than forelimbs with wobblers
because the UMN pathways to the pelvic limbs are more superficial
Is there usually cervical pain with wobblers?
no, unless there is secondary disk prolapse
Are forelimb signs due to wobblers usually severe or mild?
often mild or undetectable. May only see muscle atrophy of supraspinatus and infraspinatus
How is wobbler’s diagnosed?
- signalment
- history
- clinical findings
- radiographs, CSF (normal), advanced imaging
Why should animals affected with wobblers be examined for systemic dz/
infectious ddz
mature dobermans may have concurrent hypothyroidism, vWD, cardiomyopathy
What are radiographic changes seen with wobblers?
may be normal
1. tipping of craniodorsal aspect of vertebral body into spinal canal
2. stenosis of vertebral canal at cranial aspect of vertebra
collapsed disk space
3. degnerative changes in articular facets
Why should standard lateral and ventrodorsal myeloraphic views and views while traction is applied to neck be taken?
To see whether compressive lesions are reduced with traction (dynamic) or static.
can inform therapy, prognosis
What is treatment for wobblers disease?
medically
1. severe exercise restriction, corticosteroids
surgically
1. ventral decompression for disk herniation
2. distraction/fusion for dynamic lesion
3. dorsal decompression
What is the prognosis for dogs with Wobbler’s syndrome?
variable!!
depends on severity and cause
Recurrence can be a problem after fusion surgeries
What is syrinlgomyelia?
development of CSF-filled cavity anywhere within the cord
What is hydromyelia?
accumulation of excessive CSF whtin a dilated central canal
Why may syringomyelia, hydromyelia develop?
- altered CSF pressures
- loss of spinal cord parenchyma
- secondary to obstructed CSF flow due to malformations, inflammation, neoplasia
What is a relatively common cause of syringomyelia in dogs?
malformation of the skull (Chiari-like malformation) in Cavalier King Charles Spaniel. Reduces caudal fossa and displaces cerebellum and brainstem into foramen magnum
How many cavalier king charles spaniels have Chiari-like malformation? how many have syringomyelia? how many have clinical signs?
90%
50%
35%
When is the onset of clinical signs in Cavalier King Charles Spaniels with Chiari-like malformation and resulting syringomyelia?
puppies and young adults (,4)
What is the most consistent sign for cavalier king charles spaniels with syringomyelia?
- neck pain
- some may randomly vocalize or resent touching of area
- some phantom scratch
- may see muscle LMN upper lim, UMN rear limbs
- scoliosis due to LMN damage to nerves serving paraspinal muscles
How is syringomyelia in cavalier king charles spaniels diagnosed?
MRI–small caudal fossa due to hypoplastic occipital bone, cerebellar crwoing nad compression/herniation of cerebellar vermis and medulla
Fluid filled cavities in spinal cord parenchyma
What is the treatment for syringomyelia in cavalier king charles spaniels?
- analgesics
- drugs to decrease CSF (omeprazole, acetazolamide, prednisone)
- decompression of caudal fossa with occipital craniectomy