Postinfluenza Organizing Pneumonia in an Older Adult Successfully Treated With Corticosteroids: A Case Report

Influenza infection is usually self-limiting; however, it may occasionally trigger secondary inflammatory lung diseases such as organizing pneumonia, particularly in older adults. An 89-year-old man presented with progressive anorexia and dyspnea after a recent influenza A infection. Although he was initially managed conservatively, his respiratory symptoms worsened after a transient improvement. On admission, he had tachypnea, hypoxemia, bilateral crackles, hypoalbuminemia, elevated inflammatory markers, and mild liver dysfunction. Chest radiography and computed tomography (CT) demonstrated bilateral subpleural infiltrative opacities distributed along the bronchovascular bundles, with small pleural effusions. Based on the clinical course and imaging findings, postinfluenza organizing pneumonia was suspected. The patient was treated with systemic corticosteroids and antibiotics, followed by gradual steroid tapering. His respiratory symptoms and general condition improved steadily, and he was discharged home on hospital day 14. Follow-up CT performed one month after discharge showed marked improvement in the bilateral pulmonary infiltrates, and his functional status returned to baseline. This case highlights that persistent or worsening respiratory symptoms after influenza infection in older adults may indicate post-infectious organizing pneumonia rather than simple secondary bacterial pneumonia and that early recognition and corticosteroid treatment may contribute to favorable clinical recovery and prevention of functional decline.