Acute bouts of inflammation, Robinson said, cause mucus secretion, airway wall thickening and increased responsiveness of reflexes that initiate cough and bronchospasm. These continued attacks lead to changes in the mucosa and the smooth muscle to the point that the airway walls are thickened. Prevention of inflammation through control of environment and feed was at the heart of Robinson's message. Ideally, he said, horses, especially those suffering from respiratory ailments, should be kept outdoors on pasture and should be fed dust-free hay when pasture is unavailable. When airway obstruction must be treated, he said, bronchodilators can be effective because airway obstruction is primarily a result of bronchospasm and bronchodilators can provide relief from this respiratory distress.
Corticosteroids are still the drug of choice.
The treatment of human asthma has been revolutionized by the use of inhaled steroids. Asthmatics monitor their own lung function and adjust their steroid dose accordingly. A similar treatment modality should be our goal in veterinary medicine. The use of inhaled steroids for treatment of horses is becoming practical as convenient devices reach the market. Robinson went into detail on the medications that are available today as well as the techniques and devices used to administer them.