Noninfectious Respiratory Diseases 1

Question 1

What are some common and uncommon non-infectious equine airway diseases?

Answer 1

Common:
Equine Asthma
Inflammatory Airway Disease
Exercise Induced Pulmonary Hemorrhage

Uncommon:
Neoplasia (granular cell)
Silicosis (dust)
Equine multinodular pulmonary fibrosis
Multisystemic eosinophilic epitheliotropic disease (MEED)

Question 2

What are some other names for equine asthma?

Answer 2

COPD - Equine chronic obstructive pulmonary disease
RAO - Recurrent airway disease
Equine Asthma

Heaves, broken wind

Question 3

What is the normal signalment for a patient with asthma?

Answer 3

Middle aged (7 and up)
Recurrent, seasonal
Exposure to debris
Progressive - exercise intolerance, cough, nasal discharge, nostril flare and abdominal push

Question 4

Can you cure equine asthma?

Answer 4

No

Question 5

What are the 2 forms of equine asthma?

Answer 5

Typical Equine Heaves - dust, hay, mold, winter

Summer Pasture Arway Obstructive Disease (SPAOD) - Southeast, pasture, humid, hot

Question 6

Where can the following particles reach in the airway?
>5 microns:
1-5 Microns:
<1 Micron:

Answer 6

> 5 microns: Interial Impaction - dirt and pollen, trapped upper airway
1-5 Microns: Sedimentation, mold spore, bacteria - Upper
<1 Micron: Diffusion - gas, moisture, endotoxi - small airway and alveoli

Question 7

What is the driving force of equine asthma?

Answer 7

Inflammation

Question 8

What is the basic pathogenesis of Equine Athma?

Answer 8

Exposure to inhaled irritant
Airway neutrophilic inflammation
Bronchoconstriction and mucus hypersecretion

Question 9

Based on the history how do you know the its most likely non-infectious?

Answer 9

-Exposure to new environmental factor, seasonal, recurring
-No fever
-No other horses have it
-Gradual onset, chronic, recurring

Question 10

If you are suspicious of equine asthma, what should you check on physical exam?

Answer 10

Complete Exam
Auscultate Larynx, Trachea and Thorax
Auscultate Heart
Observe in work

Question 11

What factors influence your clinical score of asthma?

Answer 11

Abdominal Expiratory Effort
Nostril Flaring

Question 12

Do clinical signs of equine asthma correlate with disease?

Answer 12

No, few signs can be a lot of damage
-See evidence of disease then horse is very compromised

Question 13

If you need to listen to the lungs more closely you can apply a rebreathing bag. When should you not do this?

Answer 13

If they are severely compromised

Question 14

What are some diagnostics test useful for diagnosing equine asthma?

Answer 14

CBC - leukocytosis, neutrophilia, hyperfibrinogen, hyperprotieniam
Chem - hyperglobeniema (neo)
-Airway endoscopy (airway exam, mucus score, TTW
-Thoracic Ultrasound
-Rads

Question 15

What are some ways you can obtain a sample from the airway and what can you submit your sample for?

Answer 15

Transtracheal Aspirate - Cytology, PCR, Gram Stain, Culture and Sensitivity

Tracheal Brush

Bronchoalveolar Lavage - cytology, PRC, Gram Stain

Question 16

If it is your first time seeing the horse for airway issue what should you do?

Answer 16

TTW
Then can do BAL to recheck

Question 17

Where is the fluid from the transtracheal wash from?

Answer 17

Fluid in lower airway drains up toward trachea - more representative f happening in the whole airway and lung

Question 18

What does your transtracheal wash look like in a patient with asthma?

Answer 18

Moderate to high cellularity
15% non-degenerative neutrophils
Rare bacteria
Bacterial culture - negative, may have strep equi zooepidemicus
Viral PCR - negative

Question 19

What does your transtracheal wash look like in a patient with Infection?

Answer 19

High cellularity, degenerative neutrophils, increase lymphocytes
Bacterial positive
Viral PCR positive

Question 20

What is a disadvantage of a TTW?

Answer 20

May not represent current state of lower airways (has to travel there)

Question 21

When you recheck the patient, you perform a BAL … how do you know if the patient is in remission or active asthma?

Answer 21

Remission: few to mild cellularity, 5-15% non degenerative neutrophil, occasional bacteria or fungus

Asthma active - moderate cellularity, >15% nondegenerative neutrophil, occasional bacteria and fungus

Question 22

What are the goals of treating equine asthma?

Answer 22

1. Resolve immediate Disease - Airway inflammation, bronchoconstriction and hypersecretions
2. Maintain Remission

Question 23

What is the number one thing that need to be done to treat equine Asthma?

Answer 23

Change the environment

-Inspect: eliminate hay, reduce dust in barn and shed, don’t make them eat out of a round bale, provide grassy pasture

Question 24

What broad categories of medications help with asthma?

Answer 24

Corticosteroids - decrease inflammation
Bronchodilators - decrease constriction and resistance
Anti-inflammatories - NSAID

Question 25

What neurotransmitter attached to the bronchial smooth muscle to determine if there will be constriction or dilation?

Answer 25

ACH

Question 26

What regulates parasympathetic modulation?

Answer 26

Antagonists: Block ACH binding
Alpha 2 Antagonist: Block Ach Release

Question 27

What are some M3 receptor antagonist that modulate parasympathetic system of lungs?

Answer 27

Atropine
Ipratropium Bromide - nebulize - localized to lung - works with inflammation
Buscopan - IV - rescue drug

Promote bronchodilation, decrease secretions and decrease gut motility lead to colic

Block constriction

Question 28

What do alpha 2 receptor agonist do?

Answer 28

Bind pre-junctional receptor - decrease ACH release at NM junction, reduce contraction
- increase mucous and water transport
-Promote smooth muscle relax

Block release of ACH

Question 29

What causes sympathetic Modulation?

Answer 29

Beta 2 agonist: smooth muscle relax and bronchodilation

Question 30

What neurotransmitters cause sympathetic innervation?

Answer 30

Epinephrine and norepinephrine from adrenals

Question 31

What is some beta 2 agonists?

Answer 31

Clenbuterol (ventipulmin) - increase HR, Sweat and excited
Albuterol - more toxic risk
Need inflammation under control for these to help

Question 32

What are some additional drugs that could be used as bronchodilators?

Answer 32

Phosphodiesterase Inhibitor
Antihistamine
Furosemide