Ch 30 - Medical conditions of the spine Flashcards

1
Q

List some examples of degenerative spinal diseases

A
  • LWN abiotrophy
  • Degenerative myelopathy
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2
Q

What is myelodysplasia?

A

An anomaly of the spinal cord resulting from incomplete closure or development of the neural tube

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3
Q

List some examples of metabolic spinal disease

A
  • Canine polioencephalomyelopathies
  • Globoid cell leukodystrophy
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4
Q

List some nutritional diseases of the spinal cord

A
  • Thiamine deficiency
  • Secondary hyperparathyroidism
  • Hypervitaminosis A (cat)
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5
Q

Where can a CSF sample be collected?
What is the maximum volume which can be collected?

A
  • Cerebellomedullary cistern
  • Lumbar subarachnoid space
  • No more than 1ml/5kg
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6
Q

What are the landmarks for entering the cisterna magna?
What structures do you pass through?

A
  • Intersection of a line between the occipital protuberance and the spinous process of C2 and a line between the cranial aspect of the wings of the atlas
  • Pass through the skin, atlanto-occipital ligament and the meninges (dura mater and arachnoid)
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7
Q

What volume of CSF is recommened for analysis?

A

0.75 - 2ml

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8
Q

What is the appropriate interarcuate space for lumbar CSF collection in dogs and cats?

A
  • L5-L6 in dogs
  • L6-L7 in cats

Spinal cord has tapered into the conus medullaris

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9
Q

How can you determine if haemorrhage within a CSF sample is iatrogenic?

A

Centrifugation - clears iatrogenic haemorrhage

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10
Q

What is xanthochromic CSF?

A

Yellow or straw-tinged CSF suggesting previous subarachnoid haemorrhage (in the absence of hyperbilirubinaemia)

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11
Q

What is used for determining a cell count on CSF?

A

Fuchs-Rosenthal chamber

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12
Q

What is the ideal timing for performing a cell count on CSF?
What can be done if this timing cannot be achieved?

A
  • Within 30min-1hr of collection
  • Refridgeration can help to stabilise the cells
  • Can add 1:1 dilution of hetastarch or autologous serum for stabilisation
  • If done, a seperate, unaltered alloquat should be provided for protein analysis
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13
Q

What is the normal WBC count of CSF in dogs and cats?

A

0-5 WBC x 10^6/L (WBC/mcL)

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14
Q

What is the normal CSF protein content in dogs and cats?

A
  • From cerebellomedullary cistern less than 250mg/L (25mg/dL)
  • From lumbar cistern less than 450mg/L (45mg/dL)

Increased protein is nonspecific and indicates a damaged BBB or increased local intrathecal IgG production

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15
Q

What are the pros and cons of antigen vs antibody serology?

A
  • Antigen testing may circumvent the problems associated with interpretation of antibody testing
  • Antigen testing is insensitivie as it required the presence of the organism in the sample being tested
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16
Q

What is an IgG antibody index?

A

IgG Index = IgG CSF/ IgG serum

A low index suggests the IgG migrated across the BBB whereas an elevated index indicates theat the source of the IgG is the CNS

17
Q

What test is highly suggestive of SRMA?
What is the sensitivity and specificity?

A

Combines elevation of CSF and serum IgA
- sensitivity 91%
- specificity 78%

18
Q

What is the sensitivty and specificity of PCR for the diagnosis of specific viral meningoencephalitis when the CSF is tested between 48hr and 10 days after onset of signs?

A
  • Sensitivity over 95%
  • Specificity over 99%

When combined with serologic testing, chances of diagnosis are maxmimised

19
Q

List 4 reasons that a negative PCR does not definitively rule out infectious meningoencephalitis

A
  • In individual PCR test may be inherently insensitive
  • Nucleic acids may be present in CSF at undetectable levels
  • Nuclei acids from organisms may be present within the CNS parenchyma but not in the CSF
  • The disorder may have been triggered by a pathogen which is no longer present
20
Q

Define degenerative myelopathy
What breeds are overrepresented?
What gene is effected?

A
  • Diffuse axonopathy associated with necrosis primarily in the lateral and ventral funiculi of the TL spinal cord segments, accompanied by secondary demyelination and astrogliosis
  • GDS, Corgis, Boxer, Rh. Ridgeback
  • Missense mutation in the superoxide dismutase (SOD1) gene causing progressive superoxide radical-induced axonal and myelin degeneration within the spinal cord
21
Q

Define SRMA
What breeds are overrepresented?

A
  • A systemic immune disorder characterised by inflammatory lesions of the leptomeninges and associated arteries that typically respond to corticosteroids
  • Beagles, Boxers, Bernese Mt Dogs, Weimeraners, NSDT Retrievers
22
Q

What vessels can also be effected by SRMA? What other disease is often seen concurrently?

A
  • Vessels of the heart, mediastinum and thyroid glands
  • Occassionally concurrent IMPA
23
Q

What acute phase proteins are elevated in the CSF of dogs with SRMA?

A
  • CRP
  • alpha2-macroglobulin

IL-8 has also been indentified in the CSF and correlates with IgA

24
Q

What are the three forms of GME?
Define GME

A
  • Disseminated
  • Focal
  • Ocular

An angiocentric, nonsuppurative, mixed lymphoid inflammatory process affecting predominantly the white matter of the cerebrum, caudal brainstem, cervical spinal cord and meninges

25
Q

List some forms of infectious meningitis

A

Viral
- Canine distemper (guarded prognosis)
- FIP (fatal)
Protozoal
- Toxoplasma gondii (meningoencephalomyelitis OR myositis-polyradiculoneuritis)
- Neospora caninum
Bacterial
- Staph
- Pasteurella
- E.Coli
- Actinomyces
- etc..

26
Q

What IgM antibody titres are suggestive of disease of toxo and neo?

A

Greater than 1:64

Treat with clindamycin

27
Q

What are three potential sources of bacterial meningitis?

A
  • Haematogenous spread
  • Direct inoculation (wounds/needles)
  • Direct extension from other structures of the head

Use an ABx which effectively crosses the BBB (metro, enro, chloramphenicol etc) for 1-4 months post resolution

28
Q

What breeds are overrepresented for discospondylitis?

A

Great Dane, Labs, Rottweilers, GSD, Doberman, Eng Bulldog

Female GSD overrepresented for fungal disco

29
Q

What are some speculated caused of vertebral endplate infection in the development of disco?

A
  • “dead-end” capillary loop trapping circulating bacteria
  • Microtrauma associated neovascularisation of the adjacent IVD
30
Q

What are the most common patholgens isolated from disco lesions?

A
  • Staph
  • E.Coli
  • Brucella canis (zoonotic)
  • Strep
  • Klebsiella
  • Pseudomonas
  • Proteus
  • Actinomyces
31
Q

Regarding disco, what is the percentage diagnosis from blood and urine culture as apposed to percutaneous intervertebral disc aspiration?

A
  • Blood and urine culture 40%
  • Disc aspiration 60%
32
Q

What is a good empiric option for treating discospondylitis?

A
  • First-generation cephalosporins or amoxiclav
  • Good penetration of bone!
  • 17% of staph spp are resistant to first-gen cephalosporins….
  • Treat for 8 weeks
33
Q

What are some hypotheses for the entry of the fibrocartilaginous into the vessel in FCE?

A
  • Direct penetration of the fibrocartilage from the nucleus pulposus disc into the vessel
  • Remnant vessel within the nucleus pulposus
  • Herniation of a portion of the nucleus pulposus into the bone marrow and subsequent retrograde movement into the internal vertebral venous plexus
  • Neovascularisation of the degenerated intervertebral disc
34
Q

How can MRI imaging help to prognosticate in FCE lesions?

A
  • Leison-to-vertebral length ratios greater than 2, 60% unsuccessful outcome
  • Lesion-to-vertebral length ratio less than 2, 100% successful outcome
35
Q

What are some speculated caused of vertebral endplate infection in the development of disco?

A
  • “dead-end” capillary loop trapping circulating bacteria
  • Microtrauma associated neovascularisation of the adjacent IVD