Viral causes of acute respiratory infection among Egyptian children hospitalized with severe acute asthma exacerbation.

BACKGROUND: Viral respiratory infections are associated with nearly 80% of asthma exacerbation episodes. These can have severe adverse outcomes in patients with established asthma. AIM: The aim of the study was to identify the viral causes of acute respiratory infection that precipitate acute asthma exacerbation in Egyptian asthmatic children. PATIENTS AND METHODS: The current prospective study was conducted in Cairo University Children's Hospitals from December 2010 to December 2011. All asthmatic children (n=130) aged 2-12 years admitted with asthma exacerbation due to severe lower respiratory tract infection were included. All cases were subjected to nasopharyngeal or throat swabs that were analyzed for common respiratory viruses, including respiratory syncytial virus (RSV), human metapneumovirus (hMPV), influenza B (Flu B), human parainfluenza virus (hPIV), influenza A (H1N1), and adenovirus (ADV) using the real-time PCR technique. All patients were followed up to record the outcome.
RESULTS: PCR analysis was positive for one respiratory virus in 54 asthmatic patients (41.5%) and was negative in 76 patients (58.5%), with a high predominance of RSV (51.9%) and hMPV (25.9%) especially in winter and early spring months. Hypoxia was detected in all patients with RSV infection; of these patients, 21.4% were admitted to the ICU, 14.3% required mechanical ventilation, and 14.3% died. In contrast, among those with hMPV infection, hypoxia was detected in 71.4%; none required ICU admission or mechanical ventilation. CONCLUSION AND RECOMMENDATIONS: Viral etiology of lower respiratory tract infections constitutes an important cause of acute asthma exacerbation in asthmatic children admitted to children's hospitals in Cairo, supporting the need for large-scale multicentric studies on asthmatic patients over multiple years using a wider-panel PCR for detection of respiratory viruses.