Clinical Features of Severe Influenza A (H1N1) Virus Infection

OBJECTIVE: To highlight the clinical presentations of influenza A (H1N1) infection, for early diagnosis and recognition by the pediatricians. METHODS: In this retrospective study, the medical records of inpatients with influenza A (H1N1) infection between November 1, 2009 and May 31, 2011were reviewed. RESULTS: Eighty pediatric in-patients with median age 41.9 mo were studied. ARDS (11/80), pneumothorax (8/80), pleural effusion (7/80) and encephalopathy (7/80) were the most frequent complications. Six of 11 ARDS patients died;all of them were under 5 y. The median days of viral shedding was 11.4 d. Slight increase of Il-6, Il-10 and TNF-γ were revealed in some cases. CONCLUSIONS: During late stage of pandemic wave, the majority of patients were young children. Children with severe Influenza A (H1N1) are prone to develop complications, and die from ARDS. If influenza-like illness is accompanied by neurologic signs, influenza A (H1N1) virus infection should be considered. The viral shedding in children is longer than in adults.