Neuro-acute spinal cord disfunction Flashcards
What most often causes acute, non-progressive signs of spinal cord dysfunction?
- trauma
- hemorrhage
- Intervertebral disk extrussion
- fibrocartilagenous embolism
Why should you always assess the entire spine in trauma patients?
multiple spinal fractures occur in about 10% of trauma patients
What animals hemorrhage into the spinal canal?
- hemophilia A
- von willebrands
- acquired bleeding disorders
- primary or metastic neoplasia that bleeds (lymphoma, hemangiosarcoma)
What is Hansen’s type 1 disk dz?
large mass of nucleus pulposus herniates through annular fibers and enters spinal canal, bruising and compressing spinal cord
What breeds is Hansen type 1 most common in?
- daschund
- toy poodle
- pekingese
- beagle
- welsh corgi
- lhasa apso
- shih tzu
- cocker spaniel
Why do certain breeds get Hansen type 1 disk dz?
They get degeneration of intervertebral disks at a young age.
common in small breed dogs between 3-6
What large breed dogs (older) does Hansen type 1 occur in?
Basset hound Doberman (cervical vertebral instability) German shepherd Lab Dalmatian Sharpei Border collie Rottweilers
What are clinical features of Hansen type I disk extrusion?
- PAIN (with or without neuro defects)
2. signs of spinal cord injury
What causes pain in hansen type I disk extrusion?
compression of nerve roots and meninges
What are the signs of spinal cord compression in order of worsening progression?
- loss of proprioception
- ability to rise and walk
- ability to voluntarily move
- bladder control
- ability to feel deep pain
Are neurological signs with disk disease usually symmetric or asymmetric?
usually bilaterally symmetric
Why does cervical disk disease usually cause neck pain without neurological defects?
because the bony vertebral canal in this region has a very wide diameter
What do animals often exhibit with cervical disk disease?
- neck pain
- root signature
- rarely UMN to all 4 legs
What is root signature?
sign of cerbical disc dz due to compression of nerve roots or meninges, causing a pain response. affected ogs limb on one forelimb, hold it up when standing and resist movement of that shoulder through a normal range of motion
What are the signs of thoracolumbar disk dz?
- hinched back, back pain
- often neurological defects (ataxia to paralysis
UMN to hind legs (increased tone, normal to increased reflexes, ataxia, diminished proprioception)
How is disk disease diagnosed
- history
- localization of lesion
- spinal radiographs to look for disk disease
- advanced imaging
What are the major differential diagnoses for intervertebral disk disease?
- trauma
- firocartilaginous embolism
- hemorrhage
Why are spinal radiographs important when trying to diagnose intervertebral disk dz?
- rule out other dz: diskospondylitis, lytic vertebral tumor, fracture
- look for evidence of disk disease
When is a complete evaluation when IVDD is suspected recommended?
- anything that makes dx of disk extrusion uncertain
2. progression nof signs so that surgery is indicated
Why does observation of calcified disk spaces often not allow one to pinpoint the site of extrusion causing neuro dysfunction?
many dogs have multiple sites affected, some of which are old and only one that is actively causing a problem
What are radiographic signs consistent with herniation of intervertebral disk in thoracolumbar region?
- narrow or wedged disk space
- small or cloudy intervertebral foramen
- narrowing of facetal joints
- calcified density in spinal canal above involved disk
What is required to definitively localize site of an extruded intervertebal disk causing spinal cord compression in animals in which surgery is being considered?
advanced diagnostic imaging (CT, MRI, occasionally myelography)
What are drawbacks of myelography?
- they worsen menigitis and make it difficult to diagnose
2. It is difficult to tell whether the disk material is mostly on the left or right
What should always be done before myelographyt?
- collection AND analysis of CSF
When is CT most likely to be diagnostic for intervertebral disk dz?
when the extruded disk is calcified
What is the best advanced diagnostic imaging technique for localizing site and side of extruded disks?
MRI (also allows to evaluate cord parenchym)
What are three disadvantages of MRI compared to CT?
- slower than CT
- more expensive
- requires general anesthesia
What is medical treatment of intervertebral disk dz?
- strict cage confinement
2. analgesia if severe–but dont allow patient activity
What is an issue with treating dogs with IVDD with steroids?
- GI adverse effects
- decreased odds of successful outcome
- altered CSF cellularity
What are the drugs of choice for analgesia with medical treatment of IVDD?
- NSAIDs
- sometimes tramadol, gabapentin
- opiods in hospitalized patients
- muscle relaxants
How often should animals that are being medically treated for disk prolapse be monitored? why?
frequently, esp in first 24 hours because most common time for deterioration is 6-24hr
When is surgical therapy indicated in a case that is initially treated medically (IVDD)
- no improvement in 5-7d
2. if pain very severe and cannot be controlled (2-3d)
What percentage of dogs tretaed mecially for cervical or thoracolumbar disk dz will expereince relapse? What about surgically?
medically: 30%
surgically 6%
What is the essence of how to decide to pursue medical vs surgical therapy for IVDD?
if we can significantly increase the likelihood of recovery and completeness of recovery in a given dog with sx, then recommend sx
What should dogs with thoracolumbar disk dz be treated medically?
- if only have back pain
2. if have pain, proprioceptive abnormalities, rear limb weakness if can still support weight and walk
When should dogs with thoracolumbar disk dz be treated surgically?
- uncontrollable pain
- repeated epsodes of pain
- if no improvement with medical treatment within 5-7d
- severe proprioceptive and motor deficits in hind limbs so cannot support weight/walk
With dogs that have surgical decompression within 12-72hr of loss of deep pain, what is the likelihood of functional recovery
60% in small breed
25% in large breed
What is the prognosis for recovery in dogs that have lost deep pain for >72hr?
poor
When are dogs with cervical disk disease treated medically
Moderate neck pain and NO neurological deficits
When should dogs with cervical disk dz be treated surgically?
- uncontrollable severe pain
- pain that does not resolve in 2-3 days
- recurrent pain
- even mild paresis or paralysis
How are dogs with cervical disk disease treated sx?
ventral slot decompression
How are dogs with thoracic disk dz treated surgically?
hemilaminectomy
What is a traumatic type 3 disk?
acute extrusion of the nucleus pulposus into the spinal canal secondary to traumatic twisting of spine. may be degenerate or normal.
Neurologic deficits usually due to bruising of spinal cord with little compression
Why are traumatic type 3 disks not treated surgically?
because there is very little spinal cord compression. Most neuro deficits secondary to severe bruising
What is ascending descending myelomalacia?
acute forceful intervertebral disk extrusions can cause considerable hemorrhag and edema (intramedullary)
in a small number of dogs with rapid onset of REAR LIMB PARAYSIS AND LOSS OF DEEP PAIN, the damage at the site progressively causes more and more spinal damage and progressive myelomalacia of cord cranial and caudal to original lesion
What is the treatment for ascending descending myelomalacia?
euthanasia
What are the surgical treatments of choice for
a. thoracolumbar
b. cervical
c. lumbosacral?
a. hemilaminectomy
b. ventral slot
c. dorsal laminectomy
What is a preventative procedure done to prevent future disk herniation?
fenestration
What is the mechanism of fibrocartilagenous embolism?
acute infarction and ischemic necrosis of small regions of spinal cord due to fibrocartilage lodging in very small arteries
Who is fibrocartilagenous embolism common in?
medium and large breed dogs
also in mini schnauzer, yorkshire terrier, shetland sheepdog
most dogs middle aged
What are the clinical features of fibrocartilagenous embolism?
- sudden onset of neurologic signs
- may or may not be after trauma
- spinal cord lesion
- more often thoraclumbar/lumbosacral, but cervical in small breeds
- ASYMMETRY common
- dogs NOT painful by time presented to vet (may be painful first minutes of embolism)
How do you distinguish fibrocartilagenous embolism from acute IVDD, spinal cord hemorrhage and trauma?
asymmetry and absence of pain
How is FCE diagnosed?
- signalment
- history
- recognition of acute nonprogressive, nonpainful spinal cord dysfunction
- radiographs to rule out (diskospondylitis, fracture, lytic neoplasia IVDD)
EXCLUSION OF COMPRESSIVE AND INFLAMMATORY ACUTE SPINAL CORD DISORDERS
What is the appearance of spine in radiographs in animals with FCE
normal
What are the findings of CSF, CT, myelography in animals with FCE?
CSF normal or increased protein
CT and myelography normal but may see subtle swelling
Why would you perform CSF analysis, CT, MRI, myelography in an animal with suspected FCE?
to rule out compressive lesions of the spinal cord for which surgery might be indicated. MRI useful in excluding compressive myelopathy and large FCE lesions may be seen as swelling with MRI
What is the treatment for FCE?
- supportive/nursing
2. if acute maybe corticosteroids
If an animal with FCE will return to function, when does improvement start to take place? How long for complete return? If an animal shows no improvement in ________days, it is unlikely to improve
- in the first 7-10d
- 6-8weeks
- 21 d
Wht is the prognosis for FCE?
50% of dogs and cats recover sufficiently to be returned to owners as acceptable pets. Best if only UMN SIGNS.
What kind of clinical signs indicate that an animal with FCE will not recover?
- loss of deep pain
2. lower motor neuron signs
What is atlantoaxial instabulity?
congenital or development abnormality involving dens and stabilizing ligaments of C1 and C2
What breeds are affected by atlantoaxial instability?
- yorkshire terrier
- maltese
- pomeranian
- minature schnauzers
What is usually the presentation of animals with atlantoaxial instability?
- acute onset of clinical signs after mild trauma or chronic progressive signs (localized to C1-C5)
- abnormal head carriage
- usually
What can exacerbate atlantoaxial instability during the physical exam?
neck manipulation, esp ventroflexion
What is the most effective screening test for atlantoaxial instability?
lateral radiographs (standing best) or ok on table with minimal restraint
What is seen on lateral radiographs with atlantoaxial instabilit?
increased space between dorsal aspect of C1 and C2
What is the management for atlantoaxial instability?
- strict cage rest, neck brace for 6-8wks if no defects and in young dogs with soft bones. dogs may relapse
- ventral arthrodesis of articular facets until boney fusion complete