Influenza B Virus-associated Pneumonia in Pediatric Patients: Clinical Features, Laboratory Data, and Chest X-ray Findings

Abstract

The clinical significance of influenza B is frequently overlooked, and reports on influenza B pneumonia in children are limited. Therefore, the clinical features of associated complications have rarely been reported. The aim of this study is to evaluate the clinical characteristics in pediatric patients with influenza B virus-associated pneumonia. From January 2009 to February 2012, 389 consecutive patients under 18 years old with influenza B virus infection were enrolled into the study. Thirty-four patients were defined as the pneumonia group by clinical symptoms and chest X-ray (CXR) findings, and 90 patients who had laboratory data and normal CXR findings were recruited to form the nonpneumonia group. The age of the patients in the pneumonia group was significantly younger (median of 5.3 vs. 6.6 years). The white blood cell count (median of 7.5 vs. 5.7×10(9)cells/L) and C-reactive protein level (median of 21.1 vs. 5.7mg/L) were higher, but the hemoglobin level was lower (median of 12.6 vs. 13.2g/dL) in the pneumonia group. The CXR findings revealed that 29.4% of patients had alveolar consolidation, 32.4% had interstitial infiltration, and 38.2% had ground glass opacity. Two of four patients with pleural effusion had a positive bacteria culture, and both of them died. Pneumonia should be considered in pediatric patients with influenza B virus infection presenting with younger age, higher white blood cell count, lower hemoglobin, and higher C-reactive protein level. The CXR findings were varied. Patients with pleural effusion and positive bacterial culture may have more severity of clinical outcome.