Clinical Characteristic of Respiratory Tract Infections in Children during Pandemic Influenza (H1N1 2009) in Korea / 감염과화학요법

ABSTRACT

BACKGROUND: Since initial emergence on pandemic influenza (H1N1 2009) in Mexico on March 2009, the first case of pandemic influenza (H1N1 2009) occured on 2 May 2009 in Korea. We describe the clinical characteristics of childhood patients from pandemic influenza (H1N1 2009) and other concurrent respiratory pathogens during early phase of the pandemic influenza in Korea. MATERIALS AND METHODS: We have retrospectively studied 959 patients under age of 15 years who have visited Department of Emergency Medicine for a diagnostic test of pandemic influenza (H1N1 2009) or treatment of flu-like illness between May and September of 2009. The pandemic influenza (H1N1 2009) was detected via real-time RT-PCR and other respiratory viruses were detected via multiplex RT-PCR. RESULTS: A total of 959 patients visited Department of Emergency Medicine at Severance Hospital. Of them, 562 were tested; 124 (12.7%) were positive for pandemic influenza (H1N1 2009). Confirmed patients of pandemic influenza (H1N1 2009) were relatively older than non-H1N1 patients (7.5 years of age vs 4.6 years, P<0.001). Among histories or symptoms of patients with flu-like illness, contact history (80%) with another patient with pandemic influenza (H1N1 2009) was an important clue of the infection in early phase of pandemic. Comparing with hospitalized patients with respiratory tract infections due to other causes, lower ESR (32.9+/-23.5 mm/hour vs 11.5+/-9.2 mm/hour), hyperkalemia (4.2+/-0.3 mmol/L vs 5.2+/-3 mmol/L) and hyponatremia (137.2+/-2.5 mmol/L vs 124+/-40.5 mmol/L) were significant laboratory finding and higher cholesterol and GTP were noticed in pandemic influenza (H1N1 2009). Ten confirmed patients with pandemic influenza (H1N1 2009) were hospitalized due to pneumonia and all of them were resolved without any complication. CONCLUSIONS: Respiratory tract infections were caused not only by pandemic influenza (H1N1 2009) virus but also various respiratory viruses. Hospitalized patients, confirmed as pandemic influenza (H1N1 2009), showed a good prognosis. Age and contact history were distinct features and could be an important clue to differentiate causes in patients with febrile respiratory symptoms.