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Where do seizures localize the lesion to?
What is the main nerve evaluated when assessing tail and anal tone?
internal pudendal nerve
Horner's syndrome is damage to sympathetic nerve fibers. What are some ways these fibers are damaged?
- brachial plexus avulsion
- injury to cranial thoracic spinal cord (sympathetic fibers ascend from here)
- guttural pouch disease
- cervical sympathetic trunk injury
what are clinical signs of horner's?
- prolapsed 3rd eyelid
- sweating on affected side
Grade 0 means no deficits. What is the difference between 2 and 3?
- deficits readily seen but
- 2: confused with lameness easily
- 3: not confused with lameness easily
what is the difference between 4 and 5?
- 4: horse nearly falls, not safe
- 5: horse recumbent
If horse stands in place ok but then seems very unstable when blindfolded, what neuro disease does this lead you to?
What part of the brain does the horse NOT need to be able to walk properly?
does not need intact cerebrum (but will falter for complicated tasks)
what are some signs of paresis?
- muscle fasciculations
- difficulty backing
- toe drag/wearing toe
- "bounce" to stride
what are some ways to test paresis?
- tail pull
- sway test
- hopping in small foals
what are tests for ataxia?
- move w/head elevated
what gait is upper motor neuron sign characterized by over-reaching and high stepping?
what are some signs of proprioceptive deficits when standing? when walking?
- standing w limb crossed over the other w/o correcting
- walking: circumducting
If signs of paresis, could cerebellum, brainstem or vestibular system be involved?
paresis - brainstem
If signs of paresis, is this UMN or LMN? could it also be a musculoskeletal issue?
- UMN or LMN but more likely LMN
- also possibly MS
If signs of ataxia, could cerebellum, brainstem, or vestibular system be involved?
all 3 possible, esp. cerebellum
If signs of ataxia, is this UMN or LMN?
either but more likely UMN
Is hypometria or hypermetria associated with possible musculoskeletal problem?
Is hypometria or hypermetria associated w/ LMN?
- hypometria - LMN
- hypo/hyper - both UMN associated
What is normal CSF total protein, cell count, and color?
- TP: <100mg/dl
- < 6WBC
- no RBCs unless contamination
what is xanthocromia? what does it indicate?
previous endothelial inflammation/bleed into CSF
What should be aware of during recovery after taking myelograms?
transiently worse after taking the films (can pre-tx w NSAIDs)
list 6 cortical brain diseases?
- alpha virus encephalitis (EEE,WEE,VEE)
- west nile virus
- herpes myeloencephalitis
How long after administration is rabies vaccine effective?
what is causative agent of equine protozoal myeloencephalitis? Definitive host?
- sarcocystis neurona
How do horses get PEM?
possom eats sarcocyst in muscle tissue - poop sporocyst - horse eats sporocyst
what is the most defining clinical sign for EPM?
asymmetrical (otherwise can mimic any neuro disease)
how is EPM diagnosed?
- hx + CS
- western blot *only if horse neurological*
- CSF protein/cytology normal
what is western blot testing for? what does it mean that this test has only 89% sensitivity and 39% specificity?
- S. neurona antibodies (qualitative)
- many false positives
- *if CSF positive AND clinical signs = EPM*
what is a quantitative test for EPM w/97% specificity?
indirect immunoflorescence antibody test (IFAT)
What pathologic findings are suggestive of EPM?
perivascular cuffing w/mononuclear cells
how is EPM treated? what is efficacy of this tx?
folic acid inhibitors w/combo of antibiotics (sulfa + pyrimethamine) for 90-120 days
Coccidiostat (ponazuril) for 28days
only about 62% efficacy in both (meas. by improvement/return to function)
Should horses be vaccinated against EPM?
no, vx no longer available bc not efficacious
Are EEE/WEE/VEE reportable and/or zoonotic?
yes and yes
What is the vector and amplifying host for these alphaviruses?
- vector - mosquito (culiseta melanura)
- amplifier - birds (horse amplifies VEE only)
why is EEE/WEE/VEE known as sleeping sickness?
somnolence, recumbency, death
what are other signs seen with EEE/WEE/VEE?
- head pressing, dementia
- seizures, blindness
- Cr N deficits
- hypermetria, ataxia
what is prognosis for EEE? for WEE?
- EEE: 90% mortality (poor)
- WEE: <50% mortality (fair to poor)
what is best ante mortem test for the alphaviruses? What are problems with this test?
- horse often dies before collect convalescent titers
- vaccine antibodies interfere
what are expected CSF findings with alphaviruses?
- elevated protein
how is alphavirus diagnosed post mortem?
virus isolation from the brain
Most cases of alphavirus are in UNvaccinated horses. How long is the vaccine good for? when should it be given?
- lasts about 6 months
- give before mosquito season
Is west nile virus zoonotic? reportable?
- yes zoonotic
- not reportable
how is west nile virus transmitted? reservoir?
- birds as reservoir (crows)
what kind of virus is west nile?
flavivirdae, RNA virus
Do birds show signs of west nile virus? what is mortality in horses and humans?
- some birds die
- horse mortality 30% (much lower than alphaviruses)
- humans 10% (" ")
what are clinical signs of west nile virus?
- acute onset ataxia, *preferentially in rear limbs*
- face muscle fasciculations, tongue weakness
- (somnolence, but more w/EEE)
how is WNV diagnosed?
- IgM capture ELISA (81%sens/100%spec)
- virus isolation, PCR