Corticosteroid therapy for treatment of recurrent airway obstruction

摘要

Over the past decade, the therapeutic emphasis for asthma in human patients has shifted away from symptomatic bronchodilator therapy, and has focused on daily anti-inflammatory therapy to prevent episodes of airway obstruction. Inflammation is recognized as the underlying component in all cases of bronchoconstriction, and daily anti-inflammatory therapy can eliminate the need for symptomatic bronchodilator therapy. In addition, the National Heart, Lung, and Blood Institute has recently identified that sustained use of bronchodilator therapy results in increased morbidity and mortality in human asthmatic patients. In people, regular administration (q.i.d.) of #beta#_2 adrenergic agonists produces deterioration in pulmonary function, increased airway responsiveness, and more frequent exacerbations of bronchoconstriction within months of initiation of therapy. The role of corticosteroid therapy is to reverse underlying inflammation and alleviate bronchoconstriction and excess mucus formation. Corticosteroids are the only drug class to demonstrate sustained modification of disease course in human asthmatic patients. Despite evidence that inflammation is a key feature of allergic airway disease, anti-inflammatory therapy is only prescribed for 30 to40 percent of asthmatic patients. The majority of patients rely on symptomatic bronchodilator therapy, which may precipitate a vicious cycle of deterioration in pulmonary function and increased administration of short-acting #beta#_2-adrenergic drugs. Recurrent airway obstruction (heaves) in horses is an environmentally induced inflammatory airway disease of horses. Stabling of such horses leads to influx of neutrophils into the airway lumen and this is accompanied by airway obstruction as a result of bronchospasm, mucus accumulation and airway wall thickening. The most important treatment for this disease is modification of the environment in order to reduce exposure to the organic dust that originates in hay and bedding. Such a change can reduce inflammation and improve airway function within three to seven days. When environmental management is insufficient, it is necessary to administer anti-inflammatory drugs and, as yet, there is nothing more effective than corticosteroids. When administered inadequate doses, corticosteroids dramatically improve lung function in horses with recurrent airway obstruction.