Critical findings of severe influenza A (H1N1) pneumonia in children

Background: Pandemic influenza A (H1N1) causes severe pneumonia in children. The mechanism of development of respiratory failure in pneumonia patients remains unknown. This report describes clinical features of childhood influenza A pneumonia. Methods: The clinical and laboratory findings of 31 H1N1 pneumonia patients hospitalized in Iwata City Hospital from 1 October 2009 to 31 January 2010 were reviewed. Intubation and mechanical ventilation were required due to respiratory failure in eight patients, who were classified as the intubation group. Other patients without mechanical ventilation were classified as the non-intubation group. Clinical features and laboratory findings were compared between the two groups. Results: The median age was 6.3 years (range, 3-10 years). The male to female ratio was 22:9. Clinical manifestations of tachycardia, tachypnea and cyanosis were significant findings in the intubation group at admission. Lymphocytopenia was observed in both groups. Leukocytosis with neutrophilia was the risk factor for intubation. Conclusions: Tachycardia, tachypnea, cyanosis and leukocytosis with neutrophilia, could be useful predictors at admission to identify high-risk influenza A (H1N1) pneumonia in children.