THE CONTRIBUTION OF RESPIRATORY VIRUSES TO SEVERE EXACERBATIONS OF ASTHMA IN ADULTS

Viral infections are known to be associated with severe exacerbations of asthma in children. In contrast, there is limited data that viral i nfections evoke acute episodes of asthma that require emergency care i n adults. To determine the role of viral infections in exacerbations o f asthma in adults, we examined 33 patients who presented to the emerg ency room with 35 exacerbations of asthma between September 1990 and M arch 1991 for the presence of a viral infection. A nasal swab was obta ined for virus isolation by culture and rapid antigen detection by flu orescent staining. In 16 patients, serum was collected at initial pres entation and 3 to 4 weeks later for acute and convalescent viral antib ody titers. All patients had acute episodes of asthma ascertained by m edical history and physical examination. About 56% of the patients wit h asthma exacerbations had symptoms suggestive of viral illness. Rapid antigen detection and viral cultures for influenza A and B, parainflu enza-1, 2, 3, respiratory syncytial virus, adenovirus, and rhinovirus were negative on all patients. Likewise, in all 16 patients tested, ac ute and convalescent serologic studies did not show a significant rise in titer by complement fixation test. Thus, despite symptoms consiste nt with viral infection, viral pathogens could not be shown by current virologic techniques. This study suggests that viral infection may no t be as prevalent a precipitate of asthma in adults requiring emergenc y room treatment as is generally thought.