Asthma Like Syndrome

Asthma-like syndrome (ALS) is a nonallergic respiratory condition that is clinically identical to asthma but is not associated with persistent airway inflammation or airway hyperreactivity. This illness is common in swine confinement workers, in whom the prevalence has been reported to be as high as 25%. Approximately 20% of pig farmers had nonproductive cough and 11% experienced wheezing in one study. Veterinarians are another occupational group at risk. Swine confinement workers have increased prevalence of bronchial hyper-responsiveness. There is evidence that exposure to endotoxin, dust, and ammonia in the hog barn environment plays a key role in causing asthma-like syndrome. Slight elevation in neutrophils, lymphocytes, and macrophages in the lower respiratory tract without an increase in eosinophils has been observed in subjects challenged with inhalation exposure to the hog barn setting. Inflammation has also been observed in the lower respiratory tract of hog farmers and increased numbers of lymphocytes and neutrophils (107-115).

Asthma-like syndrome can be difficult to document in the clinical setting. The pulmonary deterioration can often be detected only by cross-shift testing. The cross-shift decline in FEVj is generally less than 10% but can range from 10% to 15% and is associated with more than 6 years of exposure.

Ensuring adequate air quality in swine/hog confinement areas is a practical preventive measure to prevent asthma-like syndrome. Respirator use reduces lower respiratory tract inflammation. Treatment may utilize corti-costeroids, but one study showed that these medications did not block the inflammatory response, which ensued after subjects were exposed to hog barn dust in an experimental setting. It is unclear whether chronic pulmonary disease can occur after developing this syndrome (116,117).

0 0

Post a comment