Heaves: Recurrent Airway Obstruction Exam 2

Question 1

What did RAO used to be called?

Answer 1

COPD: chronic obstructive pulmonary disease (now this is incorrect)

Question 2

What is RAO/Heaves/Asthma?

Answer 2

inflammatory obstructive airway disease that afflicts older horses

Question 3

What age does RAO affect?

Answer 3

horses 7 years old or older

Question 4

What is RAO initiated by?

Answer 4

inhalation of organic dusts (dusts associated with hay, bedding, etc.)

Question 5

Organic dusts

Answer 5

-allergens
-endotoxins
-molds
-other particles that can initiate lung inflammatory response

Question 6

Can RAO be cured?

Answer 6

no, it can only be managed

Question 7

How does a horse respond to the organic dusts?

Answer 7

very severe inflammatory process and bronchoconstriction

Question 8

Where is RAO more prevalent?

Answer 8

in the northern hemisphere (horses are stabled more and fed more hay)

Question 9

Is RAO genetic?

Answer 9

there is an apparent genetic component (horses housed in the same environment may get heaves while others may not)

Question 10

What is the first step in the RAO disease process?

Answer 10

a massive influx of neutrophils invade the airway lumen

Question 11

When does the first step of the RAO disease process happen?

Answer 11

when susceptible horses are moved from pasture to stable and fed hay
-it happens within 6-8 hours

Question 12

What is the second step of the RAO disease process?

Answer 12

inflammatory mediators (IL, cytokines, leukotrienes) act on cholinergic nerves and are responsible for bronchospasm

Question 13

What is the third step of the RAO disease process?

Answer 13

increased mucus production and thick viscosity leads to mucus accumulation (to capture the dust particles)

Question 14

What is the fourth step of the RAO disease process?

Answer 14

airway wall thickening: edema (acute) - swelling that comes from inflammation - and remodeling (chronic) - the muscle becomes thicker (hypertrophy, painful as muscling increases)

Question 15

Hyperresponsiveness

Answer 15

an exaggerated response

Question 16

What is a horse’s immune response to organic dust particles with RAO?

Answer 16

a hyperresponse

Question 17

What symptom of heaves is more important to treat?

Answer 17

the inflammatory process (more important than bronchoconstriction)

Question 18

What are the clinical signs of an acute episode of heaves?

Answer 18

-flared nostrils
-increased resp. rate (14-16/min)
-use of abdominal muscles to assist expiration
-anxious appearance
-intolerance to exercise

Question 19

Clinical signs of advanced stages of heaves:

Answer 19

-struggle to breath
-unable to eat
-weight loss
-heave lines (from consistent used of abdominal support in expiration)

Question 20

How is heaves diagnosed?

Answer 20

based on history and typical clinical signs

Question 21

What disease is RAO similar to?

Answer 21

summer-pasture associated obstructive pulmonary disease (warm and humid weather)

Question 22

What is the first step you have to take to manage heaves?

Answer 22

changing and controlling the horses environment

Question 23

What are the 3 principles of heaves management and prevention?

Answer 23

1. environmental control
2. corticosteroids to reduce inflammation
3. bronchodilators to relieve respiratory distress

Question 24

What can a horse with heaves not eat?

Answer 24

dry hay

Question 25

Where does a horse with heaves have to live?

Answer 25

outdoors 24/7

Question 26

What is the number one environmental elimination that needs to happen?

Answer 26

eliminating hay and bedding dust (even a little can trigger a heaves attack)

Question 27

If it is impossible to keep horse outside year-round what measures should be taken?

Answer 27

-soak hay -feed grass silage or pelleted feed -keep horse closer to barn door -use cardboard or flax bedding -don't blow or sweep barn aisles while horse is inside

Question 28

Why are NSAIDs contraindicated?

Answer 28

they decrease production of PGE2, a prostaglandin that inhibits inflammation and prevents bronchospasms

Question 29

What do corticosteroids do for heaves?

Answer 29

prevent pro-inflammatory process, prevent down-regulation of B2-adrenoceptors, increase appetite

Question 30

How should dexamethasone be used in treatment?

Answer 30

gradually reduce dose to minimum necessary -there should be improvement in 3-7 days (on lowest dose possible)

Question 31

What two drugs used for treatment are not FDA approved?

Answer 31

-beclomethasone -fluticasone

Question 32

Beclomethasone and fluticasone treatment

Answer 32

must be given by use of aeromask (if the obstructions prevents inhalation (too severe) bronchodilators may have to be given first)

Question 33

What are bronchodilators useful for?

Answer 33

acute heaves attacks

Question 34

What are common Aeromask bronchodilators given?

Answer 34

-albuterol -pirbuterol -salmeterol

Question 35

What is the common bronchodilator given (not with aeromask)?

Answer 35

clenbuterol (ventipulmin) - has side effects like heart palpitations

Question 36

What are the two long lasting bronchodilators and how long do they last?

Answer 36

-clenbuterol and salmeterol -6-8 hrs.

Question 37

What are the two short acting bronchodilators and how long do they last?

Answer 37

-albuterol and pirbuterol -1-2 hrs.

Question 38

Side effects of bronchodilators:

Answer 38

-sweating -trembling -tachycardia -agitation

Question 39

Which bronchodilators are side effects mostly seen with?

Answer 39

systemic administrated drugs (clenbuterol) not drugs given via inhalation

Question 40

B-1 =

Answer 40

heart

Question 41

B-2 =

Answer 41

lungs

Question 42

Prognosis depends on what?

Answer 42

the stage of disease at the time of diagnosis and the level of care provided to the horse

Question 43

What is important to do all the time?

Answer 43

prevent; continual prevention of exposure to organic dusts

Question 44

When should bronchodilators be used?

Answer 44

during acute heaves attacks or right before exercise

Question 45

Horses with heaves can do what level of work when under the right conditions?

Answer 45

low-moderate work