H1N1 influenza: Initial chest radiographic findings in helping predict patient outcome

Galit Aviram*, Amir Bar-Shai, Jacob Sosna, Ori Rogowski, Galia Rosen, Iuliana Weinstein, Arie Steinvil, Ofer Zimmerman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


Purpose: To retrospectively evaluate whether findings on initial chest radiographs of influenza A (H1N1) patients can help predict clinical outcome. Materials and Methods: Institutional review board approval was obtained; informed consent was waived. All adult patients admitted to the emergency department (May to September 2009) with a confirmed diagnosis of H1N1 influenza who underwent frontal chest radiography within 24 hours were included. Radiologic findings were characterized by type and pattern of opacities and zonal distribution. Major adverse outcome measures were mechanical ventilation and death. Results: Of 179 H1N1 influenza patients, 97 (54%) underwent chest radiography at admission; 39 (40%) of these had abnormal radiologic findings likely related to influenza infection and five (13%) of these 39 had adverse outcomes. Fifty-eight (60%) of 97 patients had normal radiographs; two (3%) of these had adverse outcomes(P =.113). Characteristic imaging findings included the following: groundglass (69%), consolidation (59%), frequently patchy (41%), and nodular (28%) opacities. Bilateral opacities were common (62%), with involvement of multiple lung zones (72%). Findings in four or more zones and bilateral peripheral distribution occurred with significantly higher frequency in patients with adverse outcomes compared with patients with good outcomes (multizonal opacities: 60% vs 6%, P =.01; bilateral peripheral opacities: 60% vs 15%, P =.049). Conclusion: Extensive involvement of both lungs, evidenced by the presence of multizonal and bilateral peripheral opacities, is associated with adverse prognosis. Initial chest radiography may have significance in helping predict clinical outcome but normal initial radiographs cannot exclude adverse outcome.

Original languageAmerican English
Pages (from-to)252-259
Number of pages8
Issue number1
StatePublished - Apr 2010
Externally publishedYes


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