Heaves: Recurrent Airway Obstruction Exam 2 Flashcards

1
Q

What did RAO used to be called?

A

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

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2
Q

What is RAO/Heaves/Asthma?

A

inflammatory obstructive airway disease that afflicts older horses

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3
Q

What age does RAO affect?

A

horses 7 years old or older

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4
Q

What is RAO initiated by?

A

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

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5
Q

Organic dusts

A

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

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6
Q

Can RAO be cured?

A

no, it can only be managed

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7
Q

How does a horse respond to the organic dusts?

A

very severe inflammatory process and bronchoconstriction

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8
Q

Where is RAO more prevalent?

A

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

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9
Q

Is RAO genetic?

A

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

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10
Q

What is the first step in the RAO disease process?

A

a massive influx of neutrophils invade the airway lumen

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11
Q

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

A

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

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12
Q

What is the second step of the RAO disease process?

A

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

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13
Q

What is the third step of the RAO disease process?

A

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

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14
Q

What is the fourth step of the RAO disease process?

A

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

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15
Q

Hyperresponsiveness

A

an exaggerated response

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16
Q

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

A

a hyperresponse

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17
Q

What symptom of heaves is more important to treat?

A

the inflammatory process (more important than bronchoconstriction)

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18
Q

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

A

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

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19
Q

Clinical signs of advanced stages of heaves:

A

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

20
Q

How is heaves diagnosed?

A

based on history and typical clinical signs

21
Q

What disease is RAO similar to?

A

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

22
Q

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

A

changing and controlling the horses environment

23
Q

What are the 3 principles of heaves management and prevention?

A
  1. environmental control
  2. corticosteroids to reduce inflammation
  3. bronchodilators to relieve respiratory distress
24
Q

What can a horse with heaves not eat?

A

dry hay

25
Q

Where does a horse with heaves have to live?

A

outdoors 24/7

26
Q

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

A

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

27
Q

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

A

-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

28
Q

Why are NSAIDs contraindicated?

A

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

29
Q

What do corticosteroids do for heaves?

A

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

30
Q

How should dexamethasone be used in treatment?

A

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

31
Q

What two drugs used for treatment are not FDA approved?

A

-beclomethasone
-fluticasone

32
Q

Beclomethasone and fluticasone treatment

A

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

33
Q

What are bronchodilators useful for?

A

acute heaves attacks

34
Q

What are common Aeromask bronchodilators given?

A

-albuterol
-pirbuterol
-salmeterol

35
Q

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

A

clenbuterol (ventipulmin) - has side effects like heart palpitations

36
Q

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

A

-clenbuterol and salmeterol
-6-8 hrs.

37
Q

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

A

-albuterol and pirbuterol
-1-2 hrs.

38
Q

Side effects of bronchodilators:

A

-sweating
-trembling
-tachycardia
-agitation

39
Q

Which bronchodilators are side effects mostly seen with?

A

systemic administrated drugs (clenbuterol) not drugs given via inhalation

40
Q

B-1 =

A

heart

41
Q

B-2 =

A

lungs

42
Q

Prognosis depends on what?

A

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

43
Q

What is important to do all the time?

A

prevent; continual prevention of exposure to organic dusts

44
Q

When should bronchodilators be used?

A

during acute heaves attacks or right before exercise

45
Q

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

A

low-moderate work