Traumatic, Degenerative and Toxic Disease of Equine CNS

Question 1

What are some common causes of traumatic brain injury in horses?

Answer 1

Flipping over backward, falls and collisions

Question 2

How should you proceed if you think you have a traumatic brain injury?

Answer 2

PE and Neuro Exam
-Palpate head and neck well
-Otorrhea (fluid out ears) bad sign, swelling and crepitus
-Pain make it hard to diagnose

Question 3

What is a primary vs secondary brain injury?

Answer 3

Primary - from trauma to CNS and blood vessel in brain
-Coup -direct - countercoup - opp

Secondary - side effects - edema, increased ICP, hemorrhage, ischemia, ischemia, inflammatory cytokines

Question 4

How can you diagnose traumatic brain injury?

Answer 4

Rads (orthogonal view) or CT

Question 5

What are the treatment goals of TBI?

Answer 5

Decrease ICP but keep good cerebral bloodflow (hypertonic and feed elevated)
Decrease inflammation and pain
Prevent sepsis
Keep standing
Treat seizures
Steroids and DMSO controversial

Question 6

Do TBI usually need surgery?

Answer 6

Medicine 1st then surgery - not great surgical candidates
-Leave bone fragments sometimes and vertebral medical may be enough

Question 7

When is the best time to address TBI?

Answer 7

1st 24-48hrs - longer = poor prognosis

Question 8

What are some degenerative CNS diseases of horses?

Answer 8

NAD, eDM, EMND, Dysautonia and THO

Question 9

What does eNAD and EDM stand for? Are they the same thing?

Answer 9

eNAD - equine neuroaxonal dystrophy
EDM - equine degenerative myeloencephalopathy

Different but cant tell unless dead

Question 10

What causeses eNAD and EDM?

Answer 10

Inherited disorder linked to vitamin E deficiency

Question 11

What are clinicla signs of eNAD and EDM?

Answer 11

Symmetric ataxia and CP deficity in all limbs
Abnormal stance at rest
thoracic and pelvic limb weak and spactis, pelvic worse
excessive hypermetria when head elevated
-Ataxia 1-2yr of life
Sign- decreased menace and lack of fight or flight response

Question 12

What are signs of eNAD or EDM on histo?

Answer 12

Spheroids, axonal loss, demyelination caudal brainstem and spinal cord (see vacuoles)

Question 13

What is the genetic cause of EDM?

Answer 13

Autosomal dominant incomplete penetrance mode inheritance

Question 14

What also has to happen for you to see signs of EDM in addition to having the gene?

Answer 14

Oxidative damage from lack vitamin E
(risk factors - insecticide, wood preservative, dirt lot, low VE)

Question 15

Can vitamin E supplementation reverse eNAD and EDM?

Answer 15

No but prevents from getting worse

Question 16

Is low vitamin E present in all eNAD and EDM horses?

Answer 16

No, some metabolize it faster and some excrete more

Question 17

What are some differential diagnosis for eNAD and EDM?

Answer 17

Cervical vertebral compressive myelopathy, EPM and Viral encephalitis, EHV and WNV

Question 18

What is the target serum Vitamin E concentration?

Answer 18

> 3ug/ml

Question 19

What kind of vitamin E should you supplement with?

Answer 19

Water soluable, natural RRR alpha tocopherol

Question 20

What is EMND?

Answer 20

Equine Motor Neuron Disease

Question 21

What causes EMND?

Answer 21

Acquired
Vitamin E deficiency
With eNAD and EDM many times

Question 22

What are signs of EMND?

Answer 22

Neuromuscular weakness and muscle atrophy (gluteal)

Subacute- symmetrical muscle atrophy, muscle fasiculations, weight shift, toe drag and weakness

Chronic- poor performance, failure to gain weight, atrophy

Pigment retinopathy

Question 23

How do you diangose EMND?

Answer 23

Sacrocaudalis dorsalis muscle biopsy
-low vitamin E supportive

Question 24

What is equine dysautonomia or grass sickness?

Answer 24

Acquired polyneuropathy affecting neuron of autonomic and enteric system in UK

Question 25

What organism do they thing causes equine dysautonomia?

Answer 25

Clostridium botuinum toxin

Question 26

What are clinical signs of equine dysatonomia?

Answer 26

Acute- dysphagia bilateral ptosis, GI ileus, abdominal pain, hypovolemia, sweating and muscle fasciculations

Subacute - same with large colon impaction

Chronic- same with weight loss, base narrow, leaning, dry nose and piloerection

Question 27

How do you diagnose Equine Dysautonomia?

Answer 27

Sign, phenylephrine eye challenge, histo definctive cajal cells reduction

Question 28

Prognosis for Equine dysatonomia?

Answer 28

Acute and subacute = euthanasia
Chronic change to recover

Question 29

What is Temporhiod Osteoarthropathy?

Answer 29

Adult horses any breed
-Facial nerve paralysis, vestibular disease, difficulty chewing

Question 30

What are clinical signs of THO?

Answer 30

-Facial nerve paralysis, vestibular disease, difficulty chewing
-Exposure keratitis
-Decrease lacrimation
-Ear droop
-Lip droop
-Hearing loss
-Nystagmus
-Strabismus
-Base-wide ataxia

Question 31

What are some differentials for CN VII and VIII disease?

Answer 31

THO, guttural pouch disease, TBI, otitis media interna, EPM, Extracranial mass

Question 32

What diagnostics are used to ID THO?

Answer 32

Rads, GP endoscopy, CT,

Question 33

How so you treat THO?

Answer 33

Medicine - antinflammatory and antibiotic, may have to enucleate

Surgery - ceratohyoidectomy

Question 34

What is hyperammonemia?

Answer 34

Liver fails to remove ammonia and other toxic metabolites from blood or over production leading to brain damage

Question 35

What are clinical sigs of hyperammonia?

Answer 35

Bilateral forebrain dysfunciton, behavior change, circle, head press, central blindness, stertorous breathing and seizure

Question 36

How do you diagnose ammonia toxicity ?

Answer 36

Signs, increase plasma or csf ammonia - liable run immediately

Question 37

How do you treat ammonia toxivity?

Answer 37

Oral lactulose
treat liver or enterocolitis
antinflammatory, hypertonic saline, fluid
tracheostomy, mange seizure