equine asthma

Question 1

what are the alternate names for the different types of equine asthma?

Answer 1

• Severe Equine Asthma sEA
  ◦ fomerly known as: Recurrent Airway Obstruction (RAO), Summer Pasture associated RAO (SPARAO)
• Mild to Moderate Asthma mEA
  ◦ formerly known as: inflammatory airway disease IAD

Question 2

what is the signalment, clinical signs, progression and diagnosis of mild equine asthma?

Answer 2

age - young (any age possible)
History: stabled

clinical signs:
* decreased performance
* No resting dyspnoea
* occassional cough
* >3 weeks

progression:
* Spontaneous improvement, response to treatment
* No recurrence

• Endoscopy: tracheal mucous +1 - 3+
• cytology: increased neutrophils, eosinophils and mast cells
• pulmonary function: 0/+

Question 3

what is the signalment, clinical signs, progression and diagnosis of severe equine asthma?

Answer 3

age - > 7y
history - stabled or on pasture, familial history, seasonality

clinical signs:
* decreased perfromance
* resting dyspnoea
* frequent cough
* variable time period

progression:
* long term treatment/manaement
* recurrence

• endoscopy: tracheal mucus +1- +5
• cytology - serverely increased neutrophils
• pulmonary function - ++/+++

Question 4

what are the thougths behind the aetiology of equine asthma?

Answer 4

• strong association with environment and feeding
  ◦ Airborne respirable dust (ARD)
  ◦ Breathing zone & Stable zone
• non-allergic inflammatory responses:
  ◦ Endotoxin, moulds, noxious gases
• genetic or familial
  ◦ familial risk for moderate/severe CS
  ◦ RAO - criterion of heritability soundness in breeding stallions
• hypersensitivity reaction
  ◦ exacerbation w/ hay dust
  ◦ allergic reaction? - HS type I and III
  ◦ possible role:
  ‣ Faenia rectivirgula
  ‣ aspergillus fumigatus
  ‣ thermoactinomyces vulgaris

Question 5

what is the breathing zone?

Answer 5

30cm around a horses nose where they breath in air from

Question 6

what is the pathophysiology of asthma?

Answer 6

• airway hyper-responsiveness
• bronchospasm
• inflammation
  ◦ mucous accumulation
  ◦ tissue remodelling

Question 7

what tissue remodleing occurs with equine asthma?

Answer 7

• increased smooth muscle mass
• increased contraction force
• peribronchial fibrosis
• epithelial hyperplasia
• bronchiectasis (widen and thicken)

Question 8

what is the overal cytology seen with asthma?

Answer 8

neutrophilia

Question 9

what are the general principles for diagnosing asthma?

Answer 9

• history
• PE
• auscultation
  ◦ rebreathing bag (look for tolerance, cough, recovery)
  ◦ specially important for mEA
  ◦ Wheezes, crackles, tracheal ratles
• endoscopy
  ◦ rule out upper airway diseases
  ◦ tracheal mucus
  ◦ 1h post-exercise
  ◦ carina thickening