A 59-year-old man who had no underlying diseases except for obesity was referred to a private clinic with fever and sore throat. A rapid diagnostic test for influenza using the throat swab was performed and the result was negative. His symptoms did not improve, and he developed shortness of breath and inspiratory crackles in both lung fields, resulting in his transfer to a medium-sized hospital.
A rapid antigen test for influenza using the throat swab was negative again, and thus, the patient was considered to have acute interstitial pneumonia based on chest radiological findings (Figure 1), and bronchoalveolar lavage (BAL) as well as transbronchial lung biopsy (TBLB) was performed (Figure 2A, demonstrating a diffuse alveolar damage compatible with acute interstitial pneumonia). Using BAL fluid, PCR for pandemic H1N1 2009 was positive. In addition, a rapid diagnostic test for influenza A was also positive using BAL fluid (Figure 2B).
Chest X-ray and chest CT findings of patient Both chest X-ray and chest CT demonstrate ground-glass and infiltrative shadow in both lung fields.