Imaging findings in a fatal case of pandemic swine-origin influenza A (H1N1)

Abstract

Objective: Although most cases of swine-origin influenza A (H1N1) virus (S-OIV) have been self-limited, fatal cases raise questions about virulence and radiology's role in early detection. We describe the radiographic and CT findings in a fatal S-OIV infection.

Conclusion: Radiography showed peripheral lung opacities. CT revealed peripheral ground-glass opacities suggesting peribronchial injury. These imaging findings raised suspicion of S-OIV despite negative H1N1 influenza rapid antigen test results from two nasopharyngeal swabs; subsequently, those results were proven to be false-negatives by reverse transcriptase polymerase chain reaction. This case suggests a role for CT in the early recognition of severe S-OIV.

Fig. 1

Middle-aged man with no history of chronic pulmonary disease presented to emergency department with 5-day history of fever, fatigue, nausea, and diarrhea. He complained of intermittent cough for approximately 3 days and confusion the night before presenting to the hospital. Radiography and CT were performed. Unenhanced chest CT lung window images showed multifocal peripheral ground-glass opacities involving all lobes. Patient died on fifth hospital day. A, Chest radiograph obtained at clinical presentation shows peripheral opacities. B, Unenhanced chest CT lung window image shows apical patchy peripheral ground-glass opacities. C, Unenhanced chest CT lung window image reveals that upper lobe and superior segments of both lower lobes show peripheral peribronchial ground-glass opacities. D, Unenhanced chest CT lung window image reveals that lingula, right middle lobe, and both lower lobes show patchy, peripheral, rounded, peribronchial ground-glass opacities with air bronchograms. E, Unenhanced chest CT lung window image shows bilateral lung bases with ground-glass opacities still predominantly patchy at periphery, but more confluent ground-glass attenuation. F, Magnified view of anterior segment of right upper lobe shows ground-glass opacity peripherally and air bronchograms (arrows).