Horse Health And Disease: Lesson 8

Front 1

What is the vertebral formula for the horse?

Back 1

C7 T18 L6 S5 C15-21
* Think 7 before 6 before 5. Sum them and you get 18.

Front 2

Where does the spinal cord end?

Back 2

S2

Front 3

What are the segments of the spine starting from head to tail?

Back 3

cervical (c), thoracic (t), lumbar (l), sacral (s), caudal (cd)

Front 4

What are the meninges?

Back 4

-pia mater
-dura mater
-arachnoid

Front 5

How are spinal nerves made up?

Back 5

Dorsal and ventral roots that exit at intervertebral spaces.

Front 6

What is the difference between afferent and efferent neurons (roots in this case)?

Back 6

efferent: away from spine to body parts
afferent: towards the spine from sensory neurons of body (like fingers for example)

Front 7

What type of neurons are motor neurons? Sensory neurons?

Back 7

motor=efferent (signals must go out of spine to area that needs to move)
sensory=afferent (signals come towards spine to translate from fingers/sensory receptors).

Front 8

Which neurons are the dorsal and ventral roots?

Back 8

dorsal= sensory/afferent
ventral= motor/efferent

Front 9

Where is the diameter greatest in the vertebral canal and why? Where does is begin to lessen?

Back 9

At the atlas to allow for head movement without spinal constriction.
It lessens at the axis.

Front 10

Where does the spine widen again?
Where is it smallest?

Back 10

-Two spots: cervical intumescence and lumbar intumescence.
-Smallest at mid-thoracic region

Front 11

What are the 6 major neurological diseases we studied in class?

Back 11

1) Equine protozoal myeloencephalitis (EPM)
2) West Nile Virus (WNV)
3) Cervical vertebral stenotic myelopathy (wobbles)
4) Equine herpesvirus 1 myeloencephalopathy (rhinopneumonitis)
5) Equine degenerative myeloencephalopathy
6) Equine motor neuron disease

Front 12

What is the most commonly diagnosed neurological disease?

Back 12

EPM (equine protozoal myeloencephalitis)

Front 13

What is the number one way to determine EPM? WNV? Wobbles? Rhinopneumonitis? EDM? Motor neuron disease?

Back 13

EPM: CSF
WNV: blood test
Wobbles: myelogram
Rhino: serology/nasopharyngeal swabs
EDM: Vit. E levels
Motor: No loss of coordination!

Front 14

What causes EPM?

Back 14

Ingestion of sarcocystis neurona.

Front 15

What are the natural carriers of sarcocystis neurona?

Back 15

Birds and oppossum.

Front 16

Describe EPM's effect on horses?

Back 16

-Infects brain and spinal cord
-Horse is dead-end host
-obscure lameness
-progressive, asymmetric ataxia
-facial paralysis/muscle atrophy
-head tilt/trouble swallowing
-wide range of severity

Front 17

How can you test for EPM?

Back 17

-use clinical signs
-blood test (30% of time= false positive)
-CSF (cerbrospinal fluid) tap

Front 18

Where are CSF taps done?

Back 18

Between atlanto-occipital space
or lumbo-sacral space

Front 19

What is the treatment of EPM?

Back 19

-anti-protozoal medication such as Marquis
-treat for 8-12 weeks
+/- 60% success rates

Front 20

What is the natural resevoir for WNV?

Back 20

Birds

Front 21

How is WNV transmitted?

Back 21

Through insect bites (horses and humans are dead end hosts)
*Found in all states

Front 22

List clinical signs of WNV from most common to least common

Back 22

ataxia/incoordination, depression/apprehension, weakness, stumbling/falling down, death, fever, anorexia, hyperesthesia, hypermetria, excessive sweating, disorientation, teeth grinding/bruxism, weight loss.

Front 23

What is the incubation period of WNV and what does this cause?

Back 23

+/- 2 weeks causing encephalitis

Front 24

How do you diagnose WNV?

Back 24

-clinical signs
-serology
-CSF tap
-post mortem

Front 25

How can you treat and prevent WNV?

Back 25

Treat: none specific, supportive
Prevent: Vax, mosquito control

Front 26

What causes "wobbles"?

Back 26

-malformation of cervical vertebrae
-narrowing of the vertebral canal
-compression and damage to spinal cord
-DOD

Front 27

What are clinical signs of wobbles?

Back 27

-mild signs to complete paralysis
-ataxia, spasticity, weakness
-generally worse in pelvic limbs, but all affected
-generally symmetric signs
-most common in TB, QH @ 1-3 years (more common in colts).

Front 28

How do you diagnose wobbles?

Back 28

-use clinical signs and signalment
-radiography (myelogram)

Front 29

How do you treat wobbles?

Back 29

-conservative
-surgical using vertebral fusion/stabilization

Front 30

What does stenotic mean?

Back 30

Constriction

Front 31

What are clinical signs of rhinopneumonitis?

Back 31

-may follow upper respiratory outbreak by 7-14 days
-acute onset of ataxia, weakness, swelling
-may be bladder paralysis
-signs usually occur acutely, progress for 1-3 days and then stabilize
-most recover fully

Front 32

How can you diagnose rhinopneumonitis?

Back 32

-use clinical signs and history
-virus isolation (nasopharyngeal swabs)
-serology (acute and convalescent samples
-CSF tap (look for xanthoghromia and elevated protein)

Front 33

How do you treat rhinopneumonitis?

Back 33

Isolation
supportive

Front 34

What causes equine degenerative myeloencephalopathy (EDM)?

Back 34

Not sure yet.

Front 35

How can EDM be treated?

Back 35

Give vit. E if levels are low.

Front 36

EDM targets what in the body?

Back 36

Diffuse degeneration of brain and spinal cord.

Front 37

What are the signs of EDM?

Back 37

-possible familial predisposition
-may be related to Vit. E deficiency
-must consider other nutritional or toxic causes
-horses less than 3 years
-symmetric ataxia, hypermetria, weakness
-may progress to recumbency

Front 38

How do you diagnose EDM?

Back 38

-History and signs
-Vit. E levels
-necropsy

Front 39

What is the pathology of equine motor neuron disease?

Back 39

-degeneration and death of motor neurons in brain and spinal cord
-similar to human ALS (Lou Gehrig's disease)
-cause unknown

Front 40

What are the clinical signs of equine motor neuron disease?

Back 40

-any age, breed, or sex
-weight loss and muscle atrophy
-weakness
-muscle tremors (fasciculations)
-drooping head due to muscle weakness
-short strided, tentative gait
-sweating

Front 41

How can you diagnose equine motor neuron disease?

Back 41

-history and clinical signs
-muscle biopsy
-electromyography (look at nerve muscle conduction)
-possible low Vit E

Front 42

What are some other conditions with neurologic signs?

Back 42

-atlanto-occipito-axial malformations
-rabies
-encephalitis
-trauma
-cervical vertebral osteomyelitis