Stridor 2/14/17 Dr. Yvorchuck

Question 1

What is ILH

Answer 1

Left laryngeal hemiplegia

Question 2

word association:

Left Laryngeal Hemiplegia > nerve?

Answer 2

Left recurrent laryngeal n.

Question 3

word association:

Left Laryngeal Hemiplegia > involvement

Answer 3

Cricoarytenoid dorsalis mm. (CAD)

atrophy of the CAD m. on left side

Question 4

word association:

ILH > what type of -pathy

Answer 4

axonopathy

Question 5

word association:

ILH > tx of

Answer 5

“tie back” or laryngoplasty

Question 6

ILH pathophysiology

Answer 6

correlation between axon density & CAD m. volume > correlation between CAD m. volume & dysfunction (grade of LH)

distal axonopathy of RLN

large horses -> long necks

repetitive trauma (think drafts & collar worn while pulling)

trauma from othr sources (think venipuncture gone wrong)

Question 7

Non-ILH pathophysiology

(Right or Bilateral Laryngeal Hemiplegia)

Answer 7

consider as manifestation of generalaized or localized neurologic dysfunction

• perivascular injections
• Guttural pouch dz
• dz of neck & cranial thorax

Question 8

ILH CS

Answer 8

exercise intolerance

INSPIRATORY noise = “roar”

possible EIPH

Question 9

Finish the sentence:

Good to remember when you change the mechanics in respiratory tract…

Answer 9

you can have several dz occur together!

Not unusual to see DDSP + EIPH, DDSP + ILH, DDSP + EIPH + ILH

Question 10

what 2 dz won’t you see together

Answer 10

ILH developing subsequent to EE or vice versa

they have nothing to do with each other (mechanically speaking!)

Question 11

T or F

It is possible for an animal to present for a noise & not exercise intolerance

Answer 11

True

If it not working at a level that requires the full respiratory capacity there might not be a performance issue

Question 12

ILH dx

Answer 12

CS & Hx

ENDOSCOPY (may require treadmill eval)

EXTERNAL ULTRASOUND

external laryngeal palpation (feel for asymmetry)

Question 13

describe how to tell which side is affected

Answer 13

when the arytenoid m. is atrophied the arytenoid will be position more axial

draw line straight down from center and see which side is smaller width -> affected side!

Question 14

what is grading system for laryngeal function (not grading laryngeal hemiplegia)

Answer 14

Grade 1 - Normal

Grade 2 - Asynchronous movement/ full abduction

Grade 3 - asynchronous movement/ incomplete abduction

Grade 4 - complete paralysis

Question 15

since the grading system is at rest, when do you need endoscopy at exercise?

Answer 15

if a horse has a Grade 3!

• there are subgroups of grade 3s the important one is the Grade 3 that at exercise is: asynchronous. but abducts fully, and stays abducted - in that case even though the animal has LH that is probably not the cause of exercise intolerance!*
• the other type is the one that initially abducts fully (still asynchronous) but then fatiques and does not (turning into an obstruction).*

Question 16

LH Tx

Answer 16

Determine Goal &/or presenting complaint (e.g. noise)

possible ventriculochordectomy alone (just correcting noise)

in drafts often done bilaterally as standing sx

To reestablish airway mechanics = Sx

LARYNGOPLASTY (“tie back”)

bilateral VENTRICULOCHORDECTOMY

occasionally - arythenoidectomy

Question 17

why would you want to do a standing ventriculochordectomy in a draft horse

Answer 17

concerns about post anesthetic myopathy (with GA)

Question 18

what is your dx

Answer 18

EE