Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Equine Medicine > Infectious Diseases of the Nervous System > Flashcards

Infectious Diseases of the Nervous System Flashcards

1
Q

What is the most frequent etiology of equine protozoal myeloencephalitis? What other microorganism can cause it? Where is this disease most common?

A

Sarcocystic neurona - obligate intracellular Apicomplexa

Neospora hughesi

USA —> NA opossums!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are environmental/management, horse, and parasite risk factors that increase likelihood of EPM development?

A

stress, season, housing, food, region

use/breed, age, number, immunity

type, number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the lifecycle of Sarcocystis neurona like?

A

3 hosts

  • DH - opossum
  • IH - raccoons, house, armadillos, skunks
  • aberrant hosts - horse ingestion of contaminated food or water with opossum feces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the suspected Neospora hughesi lifecycle?

A

indirect (2 hosts)

  • DH - carnivores (dogs?)
  • IH - ungulates (horses?) due to ingestion of contaminated food/water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the pathogenesis of EPM?

A
  • inflammation
  • neuronal necrosis
  • lack of clearance from CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What 2 macroscopic lesions are seen with EPM? Where is this most commonly found?

A
  1. multifocal hemorrhage
  2. foci of malacia and discoloration

gray and white matter of the spinal cord and brainstem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What 3 microscopic lesions are seen with EPM?

A
  1. parasite observed
  2. diffuse nonsuppurative inflammation and necrosis
  3. perivascular infiltration of mononuclear cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the most common signs seen with EPM?

A

STALL —> the great imposter

  • stumbling or tripping
  • tilted head
  • asymmetrical muscle loss
  • lameness
  • leaning against walls

(AAA —> ataxia, asymmetry, atrophy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the best antemortem diagnostic for EPM? What allows for definitive diagnosis?

A

positive serum/CSF ratio (intrathecal Ab) - many will be seropositive due to exposure, a negative is a good rule out

post-mortem examination (micro and macroscopic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 3 FDA-approved EPM treatments?

A
  1. Sulfonamide/Pyrimethamine
  2. Ponazuril (triazine antiprotozoal)
  3. Diclazuril (triazine antiprotozoal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What form is Sulfadiazine/Pyrimethamine available in? What is its mechanism of action?

A

oral suspension - ReBalance

inhibits tetrahydrofolate synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the duration of treatment of EPM with Sulfadiazine/Pyrimethamine? How is it offered with the diet?

A

90-270 days

withhold hay 2 hours before and after

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What 3 adverse reactions are associated with Sulfadiazine/Pyrimethamine?

A
  1. anorexia
  2. intestinal issues
  3. bone marrow suppression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What formulation of Ponazuril is available? What is its mechanism of action?

A

oral paste - Marquis

acts on chloroplast-related material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the dose of Ponazuril like? What is the duration of treatment?

A

loading dose 3x normal dose for a day followed by normal maintenance dose

28 days or until no further improvement - will likely need 4-5 tubes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What formulation of Diclazuril? What is its mechanism of action? What is the duration of treatment?

A

pellets - Protazil

acts on chloroplast-related material

28 days, no loading dose needed (1 bucket)

17
Q

What are some unofficial/off-label (illegal) drugs used for EPM?

A
  • compounded Sulfadiazine/Pyrimethamine
  • Diclazuril sodium salt/IV
  • Toltrazuril (compounded with pyrimethamine) - Baycox, not approved in US
  • Decoquinate + Levamisole - Orogin, not allowed in performance horses
18
Q

Other than anti-protozoals, what are 3 other treatments used for EPM?

A
  1. anti-inflammatory - NSAIDs (Banamine), steroids if danger of recumbency
  2. anti-oxidants - DMSO, vitamin E
  3. supportive care - nutrition, preventative care
19
Q

What is the prognosis of EPM like?

A

60% improve

  • 10% relapse in 1-3 years
20
Q

What are 2 important factors used to prevent EPM?

A
  1. avoid stress
  2. reduce exposure to opossum feces - feed off ground, separate fresh water source, no wildlife access to pasture or stalls
21
Q

What are the 2 families of equine herpes virusus?

A

ALPHA
- EHV1: respiratory, abortion, neurologic
- EHV3: equine coital exanthema
- EHV4: upper respiratory (+ abortion)

GAMMA
- EHV2 an EHV5

22
Q

What is the etiology of neurologic equine herpesvirus infection?

A

EHV1 (dsDNA)

  • worldwide 80-100% of horses are infected and become carriers within their trigeminal ganglia
  • OUTBREAKS
23
Q

What are the 5 risk factors that increase the likelihood of developing neurologic herpesvirus infections?

A
  1. shedding horses kept close to susceptible horses
  2. stress
  3. season
  4. crowding, mingling with shared air space
  5. adult horses of tall breeds have a higher predisposition
24
Q

What are the 2 forms of transmission of EHV1? What is its incubation period?

A
  1. DIRECT - respiratory (commonly before clinical signs), aborted materials
  2. INDIRECT - tack, equipment, people

4-7 days

25
Q

What are the 3 phases to the pathogenesis of EHV1 infection?

A
  1. attachment and invasion of the respiratory epithelium, local LNs, and peripheral blood mononuclear cells
  2. PBMC association and viremia
  3. infection of endothelial cells, vasculitis, hemorrhage, thrombosis, and ischemia
26
Q

What is the most consistent clinical sign associated with EHV1 infection?

A

biphasic fever

27
Q

What acute signs are commonly associated with neurologic EHV1?

A

ascending ataxia and paresis

  • posterior/anterior ataxia
  • recumbency
28
Q

What cauda equina signs are associated with neurologic EHV1?

A
  • urinary and fecal incontinence
  • loss of anal tone
  • loss of sensation to perineum
29
Q

What are 2 rarer presentations of neurologic EHV1? How do patients typically progress?

A
  1. facial nerve paralysis - drooping!
  2. depression

typically stabilizs in 24-48 hr

30
Q

What samples are preferred for diagnosing EHV1?

A
  • nasal swab with viral transport medium
  • EDTA blood (within WBCs in buffy coat)

maximizes viral isolation

31
Q

What is the quickest diagnostic for EHV1? What are some additional diagnostics available?

A

PCR - gB-based test or D752/N752 markers (allows for missing new strains)

  • CSF: xanthochromia - high protein and normal cells
  • seroconversion
  • viral isolation
32
Q

What treatment is recommended in horses with EHV1?

A

isolation, quarantine, supportive care - antivirals are expensive!

  • keep standing, sternal with props, reposition recumbent
  • easy access to food and water
  • protect from trauma
  • hydration
  • evacuation of bladder and rectum
  • keep handlers safe - neurologic horses are DANGEROUS
33
Q

What 6 non-specific treatments can be used for horses with EHV1?

A
  1. NSAIDs: Firocoxib, Banamine - every day of fever and continued 3-5 days past
  2. steroids: Dexamethasone SPP
  3. antioxidants: vitamin E, DMSO
  4. antimicrobials for secondary infections: TMS, Ceftiofur
  5. virustatics ($$): valacyclovir, ganciclovir
  6. CRI Detomidine in thrashing horses
34
Q

What is prognosis of EHV1 like?

A

standing = good

recumbent > 24 hrs = reserved

35
Q

What are the 5 steps fo EHV1 outbreak management?

A
  1. quarantine of premise
  2. biosecurity - PPE, barriers
  3. confirm diagnosis with PCR in febrile and EHM horses, complete post-mortem exams, freeze serum
  4. monitor rectal temperatures 2x a day
  5. release premise in 21-28 days
36
Q

How is EHV1 infection prevented? What is not available?

A
  • biosecurity
  • monitoring
  • management

EHV1 vaccines do NOT protect against EHM

37
Q

EHV vs. EHM:

A
38
Q

What are the 5 AAEP core vaccines?

A
  1. West Nile
  2. Rabies
  3. Tetanus
  4. Eastern Equine Encephalomyelitis
  5. Western Equine Encephalomyelitis

(4 are viruses!)

Equine Medicine (33 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions