Chest radiograph findings in children with laboratory confirmed pandemic H1N1 virus infection

Introduction: Since its onset in the spring of 2009, the H1N1 pandemic has kept health-care professionals busy worldwide. Even though it often causes respiratory tract illness, reports describing the radiological manifestations in infected children are few. The purpose of this study was twofold: to review the chest radiograph findings in children with laboratory-confirmed pandemic (H1N1) 2009 influenza virus and compare them with the chest radiographic findings in children with the same symptoms but laboratory negative. Methods: Informed consent was not required by the institutional review board for this retrospective study. We identified 151 children who were tested for pandemic H1N1 virus and had chest radiographs. Chest radiographs were evaluated for the presence of airway disease including hyperinflation, subsegmental atelectasis and peribronchial cuffing, airspace disease, pleural effusion or any combination of these, and compared for H1N1-positive and H1N1-negative children, for healthy and non-healthy children separately. Results: No statistically significant difference between H1N1-tested positive children and H1N1-tested negative children was found for the proportion of abnormal chest rays (P = 1 for healthy children, P = 0.08 for children with chronic disease). For individual findings, there was no difference between H1N1-tested positive healthy children and H1N1-tested negative healthy children (P > 0.083 for each finding) In children with chronic disease, there was significantly more subsegmental atelectasis (P = 0.037) in the radiographs of H1N1-tested negative children. Conclusion: Chest radiographs have non-specific findings in cases of suspected swine flu in children and have limited value in distinguishing H1N1 from non-H1N1 viral infections for both healthy children and children with chronic disease.