Viral infections and asthma exacerbations in children – adapted from the British Medical Journal, May 13, 1995 – Tips from Other Journals
Although it is widely believed that viral respiratory infections cause exacerbations of acute asthma, numerous studies have failed to confirm or refute this concept. Johnston and colleagues investigated the association between viral infections and exacerbations of asthma in children.
A total of 108 children aged nine to 11 years completed the study. All of the study subjects previously had taken part in a community-based study of asthma. Over a 13-month period, peak expiratory flow rates were recorded twice daily and a symptom diary was completed for each child. The research team was alerted if symptom scores rose, if peak expiratory values fell by more than 50 L per minute, or if the parent suspected that the child was having symptoms. Within 48 hours of such a call, the child was visited at home and serum and nasal samples were collected for viral identification.
During the study period, peak expiratory flow rates fell a mean number of 4.13 times per child. A mean of 5.33 episodes of lower respiratory tract symptoms and 7.24 episodes of upper respiratory tract symptoms were recorded. The median delay between reduction in peak flow and onset of respiratory symptoms was one day. In one-third of the episodes of lower respiratory symptoms, this delay was two or more days. Infection with at least one virus was detected in association with 81 percent of lower respiratory symptomatic episodes and in 80 percent of reported falls in peak flow rates. The most commonly detected viruses were rhinoviruses. Coronaviruses, influenza, parainfluenza and respiratory syncytial viruses were detected much less frequently.
The authors conclude that viral infections of the upper respiratory tract, particularly with rhinoviruses, are significantly associated with exacerbations of asthma in children and that sudden severe falls in daily peak flow measurements can be used to monitor the asthmatic process. (BMJ, May 13,1995, vol.310, p.1225.)
COPYRIGHT 1995 American Academy of Family Physicians
COPYRIGHT 2004 Gale Group