Equine Neurologic Exam Flashcards
Describe NORMAL CSF in the horse
Clear, colorless
TNCC < 6
Majority mononuclear cells
protein < 100
RBC 0-1
What does xanthochromia indicate in regard to CSF cytology?
xanthochromia is when the CSF appears more yellow (normal CSF is clear)
xanthochromia indicates that RBCs were metabolized due to vasculitis or trauma.
what woudl you predict the TNCC would be in the CSF of a horse with bacterial meningitis?
TNCC elevated due to neutrophils
what can you infer about an elevated protein for a horses CSF?
this is a non-specific finding and is suggestive of inflammation
what do you predict the TNCC would be in a horse with viral encephalopathy?
TNCC elevated due to mononuclear cells (monocytes or lymphocytes)
How do you perform the thoracolaryngeal adductor response (slap test) and what is it evaluating?
Slap the horse over the left withers and simultaneously feel the throat for right arytenoid abduction
This tests the cervical spinal cord (af), the nucleus of CN X, and the vagus nerve + recurrent laryngeal nerve (ef).
What are components of the ‘static’ neuro exam? (there are 8)
- mentation
- stance
- cutaneous reflexes
- tail tone
- muscle symmetry
- palpation for pain and range of motion
- cranial nerve assessment
- slap test
Which areas are being assessed when performing the menace response?
CN 2 (sight)
Brain
CN 7 (blink)
What is the dazzle assessing?
CN II (sight)
brainstem
google says: CN II, the rostral colliculus, the the hypothalamus, the visual cortex, and CN VII.
what is PLR assessing?
CN II (sight)
CN III (pupil constrict.)
what CNs does the palpebral reflex assess?
CN V (sensory)
CN VII (motor, blink)
If a horse has asymmetry in the face (eye drooping, ear drooping, and masseter msucle atrophy), what cranial nerves are likely damaged?
CN VII (motor to muscles of facial expression)
CN V (motor to muscle of mastication)
If a horse couldn’t feel you touching it’s face, which CN is likely damaged?
CN V (facial sensation)
You are called ot a farm because the owner reports her horse is unable to keep food in its mouth. Upon examining the horse, you find that the jaw tone is loose and the tongue is hanging out. Which CNs might be damaged?
CN V – jaw tone, mastication
CN XII - tongue tone
CN VII – prehension
what is the function of CN IX, X, and XI?
to protect the airway by closing the arytenoids and bringing up the epiglottis.
What are components of the ‘dynamic’ neuro exam?
- walk and trot in straight line
- serpentine walk
- walk in circles
- walk with head elevated
- walk up/down hill and curb
- tail pull
Describe a grade 2 versus grade 3 on the modified mayhew grading scale
Grade 2 – consistently abnormal under special circumstances (ex. during the serpentine or hill walks)
Grade 3 – abnormal all the time
Describe the difference between Grade 4 and Grade 5 on the Modified Mayhew grading scale
Grade 4 – extremely ataxic and may fall
Grade 5 – down and unabe to rise
Describe the difference between Grade 1 and Grade 2 on the Modified Mayhew Grading Scale
Grade 1 – inconsistently abnormal under special circumstances
Grade 2 – consistently abnormal under special circumstances
Where would you localize a lesion to if the patient had mentation changes, head pressing, circling, central blindness, oand/or seizures?
the brain (CNS)
Where would you localize a lesion to if the patient was somnolent and had multiple CN deficits?
the brainstem
where would you localize a lesion to if the patient had a hypermetric gait, intention tremors, and/or paradoxic vestibular signs (head tilt and loss of balance contralateral to the side of the central lesion)?
cerebellum
T/F: a patient with a normal mentation and one or more cranial nerve deficits has peripheral nervous system disease
true – if it were central, there would be a change in mentation.
Which 2 conditions are good examples of diseases that would cause deficits in CN VII and VIII?
Temporohyoid osteoarthropathy (THO) and otitis media/interna
Cranial nerves 7 and 8 exit the skull in close proximity to one another, traveling through the guttural pouch and past the inner ear together.
T/F: guttural pouch disease can cause deficits in CN IX, X, and XII
true – these cranial nerves run through the guttural pouch
What differentiates paradoxical vestibular disease from peripheral and central?
in both peripheral and central vestibular disease, the patients head tilt would be TOWARD the lesion, they would lean/circle TOWARD the lesion, and the nystagmus would have a fast-phase AWAY from the lesion.
Whereas in paradoxical vestibular disease, the head tilt is AWAY from the lesion, the lean/circle is AWAY from the lesion, and the nystagmus fast-phase is TOWARD the lesion.
Compare and contrast the character of the ataxia in peripheral vs central vs paradoxical vestibular disease
peripheral – base-wide stance and staggering
central – proprioceptive deficits
paradoxical – hypermetrria, ipsilateral proprioceptive deficits
If a horse had a lesion in the C1-C6 spinal cord, what would be the result/deficit?
all 4 limbs would be affected and typically the pelvic limbs are worse than the thoracic because the pelvic limb motor tracts sit lateral to the thoracic limb motor tracts and are affected first.
Where would the lesion be if you had the following deficits:
- All 4 limbs affected (decreased proprioception, ataxia, paresis)
- weakness and toe dragging in the thoracic limbs
C6-T2
The weakness and toe dragging are lower motor neuron signs.
Where would the lesion localize to for the following deficits?
Thoracic limbs normal
Pelvic limbs – weakness, toe-dragging or hypermetria
Urinary and fecal incontinence but bladder is distended and NOT easily expressed.
T3-L2
What neuro exam findings would be present in a horse with a L3-S3 lesion?
- Normal thoracic limbs
- Pelvic limbs – toe dragging and weakness
- Fecal and urinary incontinent (easily expressed bladder)
- Poor tail tone
Where would you localize a lesion based on the following findings?
No ataxia
Fecal and urinary incontinent
+/- sabulous cystitis
S3-caudal
What diagnostic test can be used to diagnose CSM?
Myelogram – inject iodinated contrast into the subarachnoid space to look for narrowing of the dye columns.
highly specific, but low sensitivity
Which diagnostic is best for diagnosing THO?
CT – you will be able to see bony proliferation
Where is the easiest location to collect CSF from in horses? (easy meaning no ultrasound needed)
lumbosacral space
Locate the LS space, clip and prep, block the skin, sedate horse and have them in stocks with skilled handler, insert 18g 5.5” spinal needle and advance until subarachoid space is penetrated. Attached the syringe and aspirate 1-2 mL of fluid.
Where can we do ultrasound-guided CSF taps in horses?
C1-C2
Which CSF tap location requires general anesthesia?
Atlantooccipital space
Place horse under gen anesthesia and flex their poll. Locate the AO space, clip, and clean. Use 18g, 3.5” spinal needle to advance into the subarachnoid space.
