Rquine Asthma Flashcards
What is the neutrophil % for mild asthma
10-25% or 5% eosinophils
What % neutrophils for severe equine asthma
> 25%
Treatment for mild asthma
Immune modulation
Omega 3 supplementation
Therapy for m/sEA
Glucocorticoids
Bronchodilators
Diagnosis of equine asthma
History/physical exam
Auscultation
Rebreathing bag
Endoscopy
BAL
Phenotypes of mEA on BAL
Neutrophils >10%
Mastocytes >5%
Eosinophils>5%
sEA phenotype on BAL
Neutrophils>25%
In remission 10-20%
Degenerated with vacuolisation
What tissue remodeling occurs in equine asthma
Increased smooth muscle mass
Peribronchial fibrosis
Epithelial hyperplasia
Bronchiectasis
Pathophysiology of asthma
Hyper-responsive airway
Bronchospasm
Inflammation
Mucous accumulation
Aetiology of asthma
Non-allergenic inflammation
Genetic
Hypersensitivity reaction
Strong association with environmental particles
Difference between presentation of aEA and sEA
sEA > 7, mEA any age
CS
- sEA - performance reduced, resting dyspnoea, frequent cough
- mEA - no resting dyspnoea, occasional cough, >3weeks length
Progressions
- mEA - spontaneous improvement or drug improvement with no reoccurrence
- sEA reoccurrence requiring long term treatment
Tracheal wash procedure
30-50ml sterile saline installed where trachea is parallel to ground
Good screening, represents both lungs
Preferred c and s method
Accuracy for mEA unknown
BAL procedure
~250ml sterile saline into one lung
Good for diffuse pathology
Specific
Preferred for EA diagnosis
Cytology on tracheal samples
Macrophages most abundant, lymphocytes second
Neutrophils most common abnormalities
Eosinophils should be < 1%
Glucocorticoids
High efficacy - extensively used
Impacts on lung function, airway inflammation, bronchial remodelling but does have adverse effects
Systemic Glucocorticoids
Prednisolone - poor bioavailability
Dexamethasone - superior, lasts longer
Isoflupredone - causes hypokalemia
Treatment in acute sEA
IV dexamethasone followed by oral dexamethasone
Then followed by inhaled Glucocorticoids - beclomethasone dipronpropriate
- fluticasone
- ciclesonide - new prodrug, does not effect cortisol levels
Corticosteroids for mEA
Oral dexamethasone or Prednisolone
+ Inhaled Glucocorticoids
- beclomethasone
- fluticasone
(Tapered over 4 weeks)
Bronchodilators
Alongside glucocorticoids
Beta-adrenergic (clembuterol, Albuterol, salbutamol)
Parasympatholytics (ipratropium)
Other drugs for asthma
Interferon-alpha - can show better treatment response/decreased relapse rate
Cromoglicate - mast cell mediated
Omega 3 fatty acids
Adverse effects of drugs
Glucocorticoids
- adrenal suppression/adrenal gland atrophy)
- immune suppression
- laminitis
Systemic beta-adrenergic bronchodilators
- cardiovascular remodelling
- tachyphylaxis
Regulations
Check with BHA for drug withdrawal times for competition
How can you reduce environmental dust
Keep outside
Free of urine/manure
Hay cubes/pelleted feed
Soaked/steamed hay/haylage
Clean cool environment
Cardboard/dust free shavings
Feed from the ground
What distance from the nose is the breathing zone
30cm
How long does it take to clinical remission with changes
4-8weeks
Extra suggestions to reduce dust
Sprinkle with water before sweeping
Turn bedding banks every day
Take horses outside whilst cleaning
No indoor blowers
Avoid hay storage near horses
