Exam 1 - Equine Neurology - Cervical Lesions, EPM, & Trauma

Question 1

what are the 2 fundamental objectives of a neurological exam?

Answer 1

• neurologic or not neurologic
• localize the lesion

Question 2

ataxia is best defined as what?

Answer 2

inability to coordinate muscle activity during voluntary movement

Question 3

T/F: cervical vertebral myelopathy & equine protozoal myeloencephalitis are associated with ataxia

Answer 3

true - usually but not always for equine protozoal myelitis

Question 4

how is ataxia graded?

Answer 4

on a scale from 1-5

imprecise - subjective

Question 5

what is the most common synonym for cervical vertebral myelopathy?

Answer 5

wobblers disease

Question 6

what is cervical vertebral myelopathy?

Answer 6

abnormalities of the cervical vertebral body, processes, or foramina that cause compression of the cervical spinal cord at the level of 2 adjacent vertebrae

Question 7

what is the most common form of cervical vertebral myelopathy? what animals does it affect?

Answer 7

dynamic - compression with neck movement

younger horses

Question 8

where is the most common site of cervical vertebral myelopathy?

Answer 8

C3-C4 is most common followed by C6-C7

Question 9

what is static cervical vertebral myelopathy?

Answer 9

osseous or soft tissue changes that compress the cord regardless of movement

Question 10

what animals are affected by static cervical vertebral myelopathy?

Answer 10

typically older horses

Question 11

where is the common site of static cervical vertebral myelopathy?

Answer 11

C5-C6

C6-C7

Question 12

T/F: horses can have both dynamic & static forms of cervical vertebral myelopathy

Answer 12

true

Question 13

what causes cervical vertebral myelopathy?

Answer 13

spinal cord compression from instability or malformation

Question 14

what is the pathogenesis of cervical vertebral myelopathy?

Answer 14

unknown - probably multifactorial

Question 15

what breeds may be predisposed to cervical vertebral myelopathy because of rapid growth?

Answer 15

thoroughbreds & warm bloods

Question 16

T/F: cervical vertebral myelopathy is very similar to degenerative osseous diseae

Answer 16

True

Question 17

what is the typical signalment of cervical vertebral myelopathy?

Answer 17

usually 6 months to < 3 years, quarter horses, thoroughbreds, warm bloods, & Tennessee walkers, maybe males

animals affected can be any age or breed

Question 18

what is the common history in a patient with suspected cervical vertebral myelopathy?

Answer 18

can be acute - consider trauma

or can be subtle, slowly progressive

Question 19

what are the clinical signs seen with cervical vertebral myelopathy?

Answer 19

bilateral symmetrical ataxia, paresis, & spasticity

Question 20

what limbs are more severely affected by cervical vertebral myelopathy?

Answer 20

hindlimbs - usually at least 1 grade more severe

Question 21

T/F: signs of cervical vertebral myelopathy tend to be stable but can be progressive, wax, or wane

Answer 21

true

Question 22

what clinical signs will you see upon walking in a patient with suspected cervical vertebral myelopathy?

Answer 22

toe dragging, bunny hopping at canter, floating their front feet (can exacerbate this by elevating head), & a base wide stance at rest

Question 23

how is cervical vertebral myelopathy diagnosed?

Answer 23

signalment/history, neuro exam, & radiographs

Question 24

why can radiographs be useless in diagnosing cervical vertebral myelopathy?

Answer 24

cervical spine will often be normal in appearance

Question 25

how is myelography used in diagnosing cervical vertebral myelopathy?

Answer 25

neutral & flexed views, 50% reduction in dorsal contrast column, but not perfect

Question 26

what complications can occur with a myelogram?

Answer 26

poor recovery, worsening of signs after the procedure, seizures, & meningitis

Question 27

what is the best treatment option for cervical vertebral myelopathy?

Answer 27

interbody fusion to stabilize the vertebrae & decompress the cord - patient selection is important

Question 28

what are the limitations of using interbody fusion to treat cervical vertebral myelopathy?

Answer 28

complications, costs, missed sites ~70% of horses improve 1 grade of ataxia

Question 29

what are the treatment options using dietary restrictions for cervical vertebral myelopathy?

Answer 29

decrease carbs & proteins to 66-75% of NRC requirements, add vitamins & minerals, stall rest

Question 30

what is equine protozoal myeloencephalitis?

Answer 30

disease of horses in the americas associated with invasion of the central nervous system by apicomplexan protozoa

Question 31

what is likely the most common neurological disease of horses in texas?

Answer 31

equine protozoal myeloencephalitis

Question 32

what is the primary cause of equine protozoal myeloencephalitis?

Answer 32

sarcocytis neurona - vast majority n. hughesii - some cases

Question 33

what is the definitive host of sarcocystis neurona?

Answer 33

opossum

Question 34

T/F: EPM is transmitted horse to horse

Answer 34

false - horses are the dead end host

Question 35

how is EPM transmitted?

Answer 35

ingestion of food or water contaminated directly or indirectly with sporocysts from opossum feces

Question 36

what horses are affected by EPM?

Answer 36

any breed, age, sex!! only in north & south america!

Question 37

T/F: EPM is not reported in donkeys, mules, or non-horse equids

Answer 37

True

Question 38

what is the classical presentation of EPM?

Answer 38

progressive, asymmetrical, multifocal, ataxia, & muscle atrophy

Question 39

Why is equine protozoal myeloencephalitis the great imitator?

Answer 39

its clinical signs can represent a multitude of neurologic diseases

Question 40

how is equine protozoal myeloencephalitis diagnosed postmortem?

Answer 40

looking for presence of protozoa - can be difficult if animal received treatment

Question 41

which is more accurate in diagnosing equine protozoal myeloencephalitis, antemortem or postmortem?

Answer 41

post mortem

Question 42

how is equine protozoal myeloencephalitis diagnosed antemortem?

Answer 42

use clinical signs, CBC, & CSF analysis to help rule-in or rule-out other causes immunodiagnostic testing - serum or CSF response to treatment - this can be misleading

Question 43

what is an antemortem immunodiagnostic test for equine protozoal myeloencephalitis that is semi-quantitative?

Answer 43

western blot - looks for s. neurona specific antibodies

Question 44

what is an antemortem immunodiagnostic test for equine protozoal myeloencephalitis that is quantitative & looks for s. neurona & s. hughesii?

Answer 44

indirect fluorescent antibody test

Question 45

what is an antemortem immunodiagnostic test for equine protozoal myeloencephalitis that is quantitative & looks for s. neurona surface antigens?

Answer 45

ELISA

Question 46

why is it best to test both serum & CSF for equine protozoal myeloencephalitis?

Answer 46

exposure is widespread so the seroprevalence is high false negatives can occur in serum & CSF negative results can make EPM less likely while positive results can be harder to interpret

Question 47

what is the treatment for equine protozoal myeloencephalitis?

Answer 47

anti-protozoals, anti-inflammatory drugs, & other supportive care

Question 48

what drug is used to treat equine protozoal myeloencephalitis once daily for a minimum of 3-4 months?

Answer 48

pyrimethamine (1mg/kg) & sulfonamide (25mg/kg) - ReBalance

Question 49

what are the side effects/toxicities of pyrimethamine (1mg/kg) & sulfonamide (25mg/kg) - ReBalance?

Answer 49

diarrhea & bone marrow suppression (neutropenia & anemia)

Question 50

what anti-protozoal treatment is used once daily for a duration of 28 days for equine protozoal myeloencephalitis?

Answer 50

Ponazuril

Question 51

what are the benefits to using ponazuril for equine protozoal myeloencephalitis? cons?

Answer 51

corn oil may enhance intestinal absorption & side effects appear to be limited expensive!!!

Question 52

what drug is used to treat equine protozoal myeloencephalitis that has the same minimum treatment duration as ponazuril?

Answer 52

diclazuril

Question 53

why are corticosteroids controversial for treating equine protozoal myeloencephalitis?

Answer 53

they may promote parasite proliferation by immunosuppression

Question 54

what are the proposed benefits for using steroids for equine protozoal myeloencephalitis?

Answer 54

signs are largely attributed to inflammation associated with response to parasites - highly effective for acute CNS inflammation

Question 55

what is the treatment outcome for equine protozoal myeloencephalitis?

Answer 55

1/3 recover 1/3 have no response to treatment 1/3 have deficits after treatment 10-30% relapse

Question 56

how is equine protozoal myeloencephalitis prevented?

Answer 56

no vaccine!!! opossum proof pastures & barns, store feed & hay in a secured manner, minimize stress

Question 57

T/F: equine protozoal myeloencephalitis affects both gray & white matter (upper & lower motor neurons)

Answer 57

True

Question 58

T/F: geographic distribution of equine protozoal myeloencephalitis appears to largely be attributed to the range of the opossum

Answer 58

true

Question 59

T/F: sagittal ratios & using inter/intra vertebral measurements are believed to be helpful in making the diagnosis for cervical vertebral myelopathy - but don't always identify the specific site of compression

Answer 59

true

Question 60

if a horse with EPM has a subtle, slowly progressive onset of the disease, how do you expect the animal to present?

Answer 60

may appear to have a lameness problem initially

Question 61

if a horse with EPM has an acute onset of the disease, how do you expect the animal to present?

Answer 61

sometimes associated with trauma & neurologic signs are errantly attributed to trauma

Question 62

T/F: EPM can cause cranial nerve deficits

Answer 62

true