ANDY KANEPS: I'm Dr. Andy Kaneps of Kaneps Equine.
Today we'll discuss the neurologic examination
of the horse.
A neurologic examination is conducted
when we're concerned that the central
or peripheral nervous system may not be functioning correctly.
That dysfunction could be as subtle as a change in behavior,
for example a horse that's normally active
and alert becoming depressed, or be
as severe as stumbling and the horse having trouble standing.
The most severe manifestation of a neurologic disorder
would be with the horse laying down and unable to get up.
A neurologic examination systematically
evaluates different portions of the nervous system
and assesses whether function is normal or abnormal.
And if abnormal, to what degree of abnormality, severe or mild.
As part of the neurologic examination,
we always include a history so that we understand
if there are any new items in the horse's diet or exposure
to other types of illnesses or diseases.
An example might be equine rhinopneumonitis or EHV-1
that can cause neurologic dysfunction and starts
as a respiratory infection.
For example, did the horse go to a horse show?
Were there coughs?
Did the horse ever have a fever?
Those sorts of items are really important in narrowing down
a diagnosis.
But the physical exam still goes through a systemic examination.
The examination will usually start
with observing the horse, either free in a paddock
or in the stall.
Does the horse move normally?
What's the level of alertness of the horse?
Is the horse head pressing, for example?
When the horse turns, does the horse
stumble or seem unaware of the limb positions?
From that distance exam, we do a close-up exam.
We will usually start with evaluation
of the cranial nerves.
And those are the nerves that originate in the brain
and go to different parts of the body, particularly the head.
We check to see whether the horse can blink its eyes.
We check to see if the horse can feel a finger in a nostril,
whether or not the horse can use its tongue,
whether the horse can swallow.
Those sorts of evaluations are part of the cranial nerve exam.
The next step we usually take would
be to do mild pinpricks on the skin.
Normally, the horse will respond just
as it would with a fly on the skin by shivering the skin.
And we assess whether that's present to a normal or abnormal
degree throughout the body.
We check to see whether the horse has
normal strength of the tail.
If the horse resists tail movement when we grasp it,
that's usually quite normal.
If it's completely flaccid, then that's abnormal.
We also check whether or not the anus
has normal tone by a mild prick, such as just placing
a thermometer in.
We see that there's normal or abnormal muscle
strength in that area.
Another thing to assess, and it might
be done during the history, is whether the horse can urinate.
Is the stall wet to a normal degree,
and has the horse been observed to urinate or not.
From those general exams, we assess how the horse
manages its self-carriage.
We walk the horse back and forth in a straight line.
Does the horse track normally or abnormally?
We may introduce a log or a rail on the ground or a curb
and have the horse walk over that.
Can the horse tell that there is an obstruction on the ground?
We can also weave the horse back and forth
over objects like I just talked about.
By doing that, the horse has to fully assess its location
in relationship to the obstacle.
Does it trip over the obstacle, does
it stumble during the turns?
Those sorts of things are important to assess.
The next part of the exam is to pivot the horse
on its hind legs.
Doing that, will assess what we call proprioception.
Can the horse tell where its limbs are?
Normally, a horse will mildly cross over its back legs
as we pivot in a tight circle.
And it should do that without reaching
out far with the outside limb.
Reaching out far is called circumduction,
and that's an abnormal finding.
The next thing we can evaluate is limb strength.
We can do that in the forelimbs by pushing on one shoulder,
pushing the horse over onto the opposite leg,
and the horse should normally resist and not collapse or act
weak.
We can do the same for the hind legs by pulling the tail
and walking the horse forward.
Can the horse support its weight well
as we shift its weight onto one limb?
Another item of the exam is to walk the horse up and down
a slope.
To properly manage a slope, the horse
has to take in visual information, and its limbs
sensation, and compile that information
to keep it from stumbling.
Sometimes we'll do portions of the exam
with a towel over the eyes to eliminate the visual input.
That may show more subtle abnormalities
in proprioception and strength and full use
of the horse's body.
We record those findings and make an assessment
as to whether additional information is
needed to make a diagnosis.
If these findings show abnormal neurologic function,
appropriate samples to be taken for laboratory testing include
blood samples that can assess for various diseases ,
spinal fluid may be sampled, again,
to test for levels of inflammation and various
diseases.
From there, those laboratory findings are assessed.
And we determine whether or not imaging is indicated.
Imaging may be as straightforward as X-rays
of the neck if we suspect some type of pressure
on the spinal cord or may require a myelogram.
This is a procedure under general anesthesia
where contrast medium or dye is injected into the spinal canal.
For further information on neurologic conditions
of the horse, check the SmartPak Horse Health Library.