To inquiry the time-course of infectious asthma.

To inquiry the time-course of infectious asthma, we retrospectively examined [FEVsub1] from 5 days before to 10 days after the first brunt of illness in 31 asthmatic children (20 striplings and 11 girls), aged 8 to 12 years. Infections were confirmed on a rise of at least fourfold in serum compliment fixation titers (respiratory syncytial virus, adenovirus, and Mycoplasma pneumoniae) and hemoaggulutination inhibition titers (parainfluenza virus signs 1, 2, and 3). All the patients had 20 percent or more fall in [FEVsub1] from baseline value during acute phase, however were clinically tolerable and required minimum or no bronchodilators. Regardless of infectious agent, [FEVsub1] began to fall forward the first disease day or the previous day, and deteriorate for the first not many days. Mean(SD) maximum fall in [FEVsub1] ranged from 39(12) percent to 45(20) percent Thereafter, [FEVsub1] began to improve and replyed to the preillness level by dint of the seventh to tenth day. These rises suggest that progressive bronchial obstruction may be inevitable during the acute stage of any infectious asthma.

(Chest 1994; 106:100-04)

RSV = respiratory syncytial virus

key-note words: infectious asthma, Mycoplasma pneumoniae, respiratory virus

Infections of respiratory viruses and Mycoplasma pneumoniae, a certain number of of them of low pathogenecity to healthy children, many times provoke exacerbations of bronchial obstruction in children with asthma.(1)(2)(3) Besides, more than individual third of all severe episodes of asthma are associated with viral respiratory tract infection.(4) A previous consideration demonstrated that influenza virus infection in asthmatic children causes progressive bronchial obstruction during the acute stage of illness(5) and the progressive bronchial obstruction may superficially diminish the efficacy of bronchodilators administered in a certain quantity of patients. Therefore, it is also useful for better prediction and treatment of exacerbations of asthma to elucidate the time-course of bronchial obstruction triggered through other respiratory viral and M pneumoniae infections.

Children with asthma who were admitted to our residential treatment center received routine physical examination each day, and also performed spirometry almost each day. When the children had signs and symptoms of respiratory tract infection, paired serum specimens were examined for viral and M pneumoniae titers to identify an infectious agent. There were a certain patients with stable conditions whose episodic bronchial obstructions were considered to be triggered mainly according to a respiratory tract infection. The ready study retrospectively investigated the time-course of bronchial obstruction triggered by dint of symptomatic, uncomplicated respiratory tract infections, leaving out those caused by influenza virus infection, in these children with stable asthma; the first day of illness, was considered to be first day with low-grade fever

METHODS

Patients

Bronchial obstruction was diagnosed if wheezing was audible without stethoscope and/or there was a 20 percent or more fall in [FEVsub1] from baseline value (see below). We retrospectively studied incidence of bronchial obstruction during serologically proven 43 respiratory syncytial viruses (RSV) 54 parainfluenza virus, 27 adenovirus, and 36 M pneumoniae respiratory tract infections among 160 asthmatic children (104 lads and 56 girls), and compared it with the incidence during rubella virus infection in 16 asthmatic children (13 male childs and 3 girls). The children were 8 to 12 years antique and all of them were staying in a residential treatment center because of uncontrollable asthma at their abiding-place They all met American Thoracic Society criteria for the diagnosis of asthma.(6) No single in kind was steroid dependent or aspirin sensitive. None of them had respiratory tract infection for at least 6 weeks or clinical asthma that continued 1 day or more for at least 2 weeks before the storming of the study.

The time-course of percent fall in [FEVsub1] was retrospectively examined from 5 days before to 10 days after the storm of each illness in 31 patients (20 striplings and 11 girls) whose bronchial obstructions were clinically tolerable and required minimum or no bronchodilators among the 160 patients (Table 1)

[TABULAR DATA OMITTED]

Physical examination was done twice daily, in the morning and the evening, and wheezing during be dead was heard hourly from 8:30 PM to 6 AM. Axillary temperature was measured routinely one time in the morning, and as required.

Oral bronchodilators, a combination of short-acting salbutamol (2 mg) and aminophylline (100 mg) were given one time or twice a day through every part of the study in five patients, from the first disease day to the completion in one patient, and from the third disease day to the sixth day in the same patient. They were given in the late afternoon and before going to bed, or just before going to bed. Oral short-acting aminophylline (100 mg) was given three times a day over the study in two patients, and oral DL-isoproterenol hydrochloride (10 mg) was given three times a day from the first disease day to the period in two patients. The morning dose was given about 8 AM. Eight patients inhaled sodium cromoglycate (20 mg) (by spinhaler) three times a day, and five took oral ketotifen (1 mg) twice a day regularly from end to end the study. The morning dose of these anti-inflammatory medicines was given about 8 AM. Eight patients took as well-as; not only-but also; not only-but; not alone-but bronchodilator and anti-inflammatory medicine, and 12 patients took none of them in every part the study. Analgesic antipyretic, mefenamic acid or acetylsalicylic acid, was given as necessityed However, treatment with it was withheld for at least 10 h before the spirometry. Antimicrobial medicine was not given to any patient during the study

...