PROGRESSIVE BRONCHIAL OBSTRUCTION DURING THE ACUTE STAGE OF RESPIRATORY-TRACT INFECTION IN ASTHMATIC-CHILDREN

To study the time-course of infectious asthma, we retrospectively examined FEV(1) from 5 days before to 10 days after the onset of illness in 31 asthmatic children (20 boys and 11 girls), aged 8 to 12 years. Infections were confirmed by a rise of at least fourfold in serum compliment fixation titers (respiratory syncytial virus, adenovirus, and Mycoplasma pneumoniae) and hemoaggulutination inhibition titers (parainfluenza virus types 1, 2, and 3). All the patients had 20 percent or more fall in FEV(1) from baseline value during acute phase, but were clinically tolerable and required minimum or no bronchodilators. Regardless of infectious agent, FEV(1) began to fall on the first disease day or the previous day, and deteriorate for the first few days. Mean(SD) maximum fall in FEV(1) ranged from 39(12) percent to 45(20) percent. Thereafter, FEV(1) began to improve and returned to the preillness level by the seventh to tenth day. These results suggest that progressive bronchial obstruction may be inevitable during the acute stage of any infectious asthma.