Exam #4: Equine Respiratory Pt. 3 Flashcards

1
Q

DDx? Poor performance, hypophagia, lethargy, history of “flu and URT-like” infections, mild tachypnea, intermittent wheeze with rebreathing bag, intermittent cough and “sore throat” (2)

A

1) Exercise-induced pulmonary hemorrhage
2) Inflammatory airway disease

Others = post-viral bronchitis/bronchiolitis (based on history) or lymphoid follicle hyperplasia

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2
Q

Dx of non-febrile and poor performance respiratory disease (EIPH, IAD)

A
  • History and PE
  • CBC = often WNL
  • Endoscopy
  • Transendscopic/percutaneous tracheal wash
  • Cytology
  • Culture & sensitivity
    +/- Thoracic rads
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3
Q

What grades of lymphoid hyperplasia is normal in young horses? Abnormal in adults?

A

Young = normal = grades 1-2 out of 4

Older/adults = chronic and heavy breathing, grades 3-4

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4
Q

Common inciting agent/pathology and risk factors (2) for EIPH

A
  • Inciting agent = strenuous exercise –> extravasation of RBC’s from pulmonary capillaries
  • May have been preceded by IAD or previous viral infections
  • Risk factors = age, speed of exercise (develops more in older horses with increasing race speeds)
  • INTENSITY of exercise is more important than duration
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5
Q

Clinical signs of EIPH

A

+ Poor athletic performance = most commonly
+/- Dyspnea
+/- Excessive swallowing
+/- Coughing
+ Epistaxis, during or shortly thereafter exercise

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6
Q

Diagnosis of EIPH

A
  • History and PE
  • Endoscopy WITHIN 90 MINUTES of race (graded)
  • BAL or TTW cytology = see hemosiderophages, RBC’s, erythrocytophagia
  • Thoracic radiographs = helps r/o other disease like abscesses, tumors, IAD (interstitial)
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7
Q

Treatment of EIPH

A

> Reduce pressure in capillaries = furosemide
+/- Enalapril’s efficacy hasn’t been proven in the lungs, NO as a vasodilator
Reduce blood viscosty = pentoxyfylline (ok with EIPH)
Reduce airway obstruction = nares dilator strips
Reduce airway inflammation/bronchoconstriction = bronchodilators, corticosteroids, low allergenic bedding
Rest

+/- Hemostasis promoters (vit-K, estrogens)
+/- Inhibition of platelet aggregation = aspirin
+/- Herbals, etc.

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8
Q

Comparison of age with IAD and RAO

A
  • IAD = occurs at any age

- RAO = primarily mature to older horses that have been previously sensitized to antigens

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9
Q

Comparison of clinical signs at rest with IAD and RAO

A
  • IAD = subtle, poor performance, exercise intolerance, chronic/intermittent coughing, +/- tracheal mucus
  • RAO = overt EXPIRATORY effort at rest (heaves), severe exercise intolerance
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10
Q

Where do we sample from for cytology for EIPH, IAD, or RAO for dx? What do we see?

A
  • EIPH = sample trachea with TTW (more localized) = RBC’s, hemosiderophages, erythrocytophagia
  • IAD = BAL = mild neutrophilia, lymphocytosis, monocytosis, may see eosinophils or mast cells
  • RAO = BAL = most are neutrophils, fewer lymphocytes and monocytes, usually no mast cells or eosinophils
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11
Q

Comparison of response to treatment for IAD and RAO

A

BOTH improve with corticosteroids, bronchodilators, and environmental change

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12
Q

Comparison of inciting factors for IAD and RAO

A
  • IAD = no systemic infection, but non-infectious agents are important, Ex: aerosolized particles, dust, gases, endotoxins, mite debris, etc.
  • RAO = aerosolized allergens and endotoxins from hay and bedding

*BOTH triggered by environmental conditions so it can be hard to differentiate

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13
Q

What do the airways look like and respond like with IAD?

A
  • Lung function and gas exchange is impaired = may see evidence of hypoxemia on bloodwork
  • Evidence of airway obstruction
  • Hyperreponsive airways = secrete mucus
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14
Q

Non-infectious LRT disease treatment (IAD, RAO)

A

> Environmental and allergen management
- Use feedstuffs and bedding that are low dust and endotoxin
- Reduce airborne particles and noxious gases
- Ex: paper bedding, soaked hay, pelleted diets
Control airway inflammation = glucocorticoids (inhalation, PO, systemic), mast cell stabilizers
Bronchodilators = clenbuterol, albuterol
*Systemic glucocorticoids risk laminitis

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