Equine asthma Flashcards
What do areas of dullness within the lung fields suggest?
Suggesting pleural effusion or pulmonary consolidation/abscessation/masses
What could abnormal lung sounds suggest?
- Large airway sounds suggesting consolidation
- Wheezes and crackles suggesting airway narrowing, or discharges in airways
What does a tracheal rattle suggest?
Suggesting discharge pooling at the thoracic inlet
Causes of asthsma in foals?
- Infectious causes (usually bacterial)
- Congenital abnormality
- Sepsis, trauma, other
Causes of asthsma in weanlings?
Infectious causes (often bacterial but also parasites) & contagious
Causes of asthsma in adults?
- Disease of young adults
-
EQUINE ASTHMA SYNDROME
- Infectious causes (bacterial and viral and mycoplasma)
- Young racehorses 4-5 years where they will develop equine asthma
-
EQUINE ASTHMA SYNDROME
- Disease of old horses
- EQUINE ASTHMA SYNDROME
- Mature horse will suffer from an infectious form of equine asthma too
Clinical signs of equine asthma?
- Chronic cough
- Excess respiratory mucus production
- Poor performance
- Systemically healthy
How can you tell between Equine Asthma Syndrome and equine flu?
- Equine asthma horses will be otherwise systemically healthy
- With equine flu will be generally unwell
Which horses tend to get Recurrent Airway Obstruction?
Older horse (typically 8+)
Signs of Recurrent Airway Obstruction?
- Chronic (don’t recover and need long term environmental management)
- poor performance to overt signs of respiratory dysfunction
- expiratory effort
- with/without coughing
- Nasal discharge
- hypertrophy of the abdominal muscles (heave line in the abdominal muscles)
- Previous episodes, worsening over the years
Which horses tend to get inflammatory airway disease?
Any age, but typically younger horses
Clinical signs of inflammatory airway disease?
- Recover
- Rarely have snotty nose, don’t cough as much, typically present just with exercise intolerance
- A non-specific response to dust etc. in the environment, not infection or hypersensitivity
- Often subclinical – poor performance
What is equine asthma an umbrella term for?
- Recurrent airway obstruction
- Inflammatory airway disease
Indications for cytology?
- Horses that relapse
- Do not respond to therapy
- Check you have the right diagnosis
- Do not respond to management change
How would you sample for cytology?
- Tracheal wash (endoscopic)
- Trans-tracheal wash
- Bronchoalvealor lavage
Results of a tracheal wash in a recurrent airway obstruction case?
- Tracheal wash neutrophilia
- BALF will show at least 20% Neutrophils
- +++Mucus
Results of a tracheal wash in an inflammatory airway disease case?
- TW: Increased mucus
- Neutrophilia??
- BALF
- >5% neutrophils <20%
- > 2% Mast cells <5%
- >1% Eosinophils <5%
Management of recurrent airway obstruction?
- Environment
- Remove allergens and particles from airway
- Improves ventilation
- Remove dusty bedding and hay
- Control inflammation
- Proven benefit
- Brochodilators
- Corticosteroids
- Mast-cell stabilizers
- During remission
Management of inflammatory airway disease?
- Environment
- Remove irritants
- Remove dusty bedding and hay
- Control inflammation
- Anecdotally helpful
- Corticosteroids
- Brochodilators
- Not useful (limited constriction)
- Mast-cell stabilizers
- Reduce mast cells in BALF
Effects of Beta-agonists (Clenbuterol)?
- Bronchodilators
- Activates the SNS and opens up the airways
- Must be combined with environmental control
How are Mucolytic agents used?
- Often used at the same time as clenbuterol
- Helps to clear mucus, which is trapping the aerosols
- If not much mucus probably not worth using as quite expensive too
How useful are Mast Cell Stabilizers?
- Only useful for horses IN REMISSION
- Prevent disease
- Don’t work if the horse is showing clinical signs at the time
Advantages and disadvantages of nebulised bronchodilators?
- Rapid onset of effect
- Reduced systemic effects
- But still absorbed and therefore detectable in blood
- So affects ability to compete
How do Parasympatholytics work?
- Inhibit main bronchoconstriction pathway
- Vago-vagal effects
- Systemic side effects limit use
- Reserve for respiratory distress
- Will affect GI motility
What is Ipratropium Bromide, and what is its use?
- Inhaled parasympatholytic
- Nonselective muscarinic antagonist (like atropine)
- Also inhibits cough
- Little systemic uptake
- Duration 4 – 6 hours so a drug to give just before the animal goes out for exercise (but not before competing)
Side effects of corticosteroids?
- SUPPRESSION OF ADRENAL FUNCTION
- IMMUNOSUPRESSION
- LAMINITIS
Benefits of inhaled corticosteroids?
- Local administration
- Reduced systemic side effects
- Rapid onset of effects
- 24 hours after admin
- Taper dose to minimal effective
- But - May require systemic corticosteroids initially
Which inhaled corticosteroid do we tend to use?
- Beclomethasone - we tend to use based again on the fact it is cheaper
- Fluticasone is more potent but a lot more expensive
Why does therapy fail?
- Wrong diagnosis
- Not combined with environmental control
- Beta Receptor down-regulation
- Occurs after 2-4 weeks
- Can be offset by combination with corticosteroid
Management of the relapsing case?
- Rule out secondary bacteria
- Tracheal wash / BALF cytology
- Transtracheal culture
- Must be combined with cytology
- Care when interpreting bacterial culture
