Characteristics of atopic children with pandemic H1N1 influenza viral infection: Pandemic H1N1 influenza reveals ‘occult’ asthma of childhood

Abstract

The number of human cases of pandemic H1N1 influenza viral infection has increased in Japan since April 2009, as it has worldwide. This virus is widespread in the Yamaguchi prefecture in western Japan, where most infected children exhibited respiratory symptoms. Bronchial asthma is thought to be one of the risk factors that exacerbate respiratory symptoms of pandemic H1N1-infected patients, but the pathogenesis remains unclear. We retrospectively investigated the records of 33 children with pandemic H1N1 influenza viral infection who were admitted to our hospital between October and December 2009 and analyzed their clinical features. The percentage of children with asthma attack, with or without abnormal findings on chest radiographs (pneumonia, atelectasis, etc.), caused by pandemic H1N1 influenza infection was significantly higher than that of children with asthma attack and 2008-2009 seasonal influenza infection. Of the 33 children in our study, 22 (66.7%) experienced an asthma attack. Among these children, 20 (90.9%) did not receive long-term management for bronchial asthma, whereas 7 (31.8%) were not diagnosed with bronchial asthma and had experienced their first asthma attack. However, the severity of the attack did not correlate with the severity of the pulmonary complications of pandemic H1N1 influenza viral infection. The pandemic H1N1 influenza virus greatly increases the risk of lower respiratory tract complications such as asthma attack, pneumonia, and atelectasis, when compared to the seasonal influenza virus. Furthermore, our results suggest that pandemic H1N1 influenza viral infection can easily induce a severe asthma attack, pneumonia, and atelectasis in atopic children without any history of either an asthma attack or asthma treatment.

Viral infection of the lung: Host response and sequelae

“…Asthma exacerbations have been documented after infection with rhinoviruses, seasonal and pandemic influenza, adenoviruses, and coronaviruses. [166][167][168][169] Eighty percent of children requiring hospitalization after an acute asthma attack had a viral infection at the time of entry. 167 The mechanisms by which viral respiratory tract infection might contribute to asthma exacerbation are unclear, but current evidence demonstrates a skewed immune response in infected children.…”

Astımlı Çocukların Ebeveynlerinin Mevsimsel İnflüenza Aşısı Hakkındaki Görüşlerinin Değerlendirilmesi

“…İnflüenza virüsü ile enfekte olan astımlı hastalarda astım atak sıklığının ve şiddetinin, hastaneye yatış ve atelektazi gelişimi gibi komplikasyonların belirgin olarak arttığı (2,3), pandemik inflüenza virüsü ile enfekte olunması durumunda ise komplikasyonların daha ağır olabildiği gösterilmiştir (4,5).…”

Differences between asthmatics and nonasthmatics hospitalised with influenza A infection

“…Furthermore, we are unable to reliably distinguish between acute bronchospasm concurrent with the A/H1N1 2009 infection and exacerbation of prior asthma. Such new onset asthma or viral-induced bronchospasm is not infrequent with influenza, at least in children [11]. The prognosis of such cases in relation to influenza infection may be different.…”