746. Septal Emphysema with Refractory Pneumothorax in H1N1 Primary Viral Pneumonia
Session: Abstracts: Virology: Influenza
Friday, October 22, 2010

Background: The novel Influenza A H1N1 2009 pandemic peaked in Lebanon during the fall of 2009. Of the 1771 patients evaluated at our University Medical Center for influenza-like illness, 954 (54%) tested positive by PCR. Seventy-seven were hospitalized, 15 had severe hypoxemia and variable degrees of multi-organ failure, five required mechanical ventilation. Two patients died. The first patient was a 28-year-old female, presented with severe pneumonia. Bilateral pneumothoraces refractory to standard therapy further complicated her clinical course and she died after 8 weeks of hospitalization. The second patient was a 54-year-old male who presented with severe hypoxemia; intubation was averted with the use of non-invasive positive pressure ventilation (NIPPV) at 14/6 cm H2O. Still, he developed a pneumothorax and passed away .Pneumothoracies occurred at a high frequency, were not readily explained by barotrauma, and were associated with adverse outcome

Methods: This prompted us to perform limited cardiopulmonary autopsies to better understand the pathophysiological bases of that complication.

Results: Typical, albeit not pathognomonic findings of acute influenza were seen on microscopic examination  (Fig. 1).  Our first patient was a young, healthy, never-smoker without any previous history of pulmonary disease. She had multiples large bullae (Fig1 panel A) with cystic transformation of pulmonary parenchyma on microscopy (Fig 1 panel D).  We think that the pneumothoraces were due to the multiples large bullae acquired during the course of her illness. Gross examination showed a sub-pleural bulla in the second patient (Fig. 1. panel E) with septal emphysema and necrotizing alveolitis revealed on microscopy (Fig 1 panel H). Our patients' clinical and pathological findings do not support the typically accepted model of pneumothorax in ARDS patients where high positive pressure leads to focal alveolar overinflation with subsequent rupture.

Conclusion: Pneumothorax in patients with H1N1 pneumonia represents a serious cause of additional morbidity and increased mortality. We think that necrotizing alveolitis and septal emphysema rather than alveolar rupture and barotrauma were the underlying pathological factors in pneumothorax formation.


Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

Eid Azar, M.D. , Infectious Diseases, Balamand University, Beirut, Lebanon
George Juvelekian, M.D. , Pulmonary, Balamand University, Beirut, Lebanon
Fatima Ghandour, M.D. , Pathology, Balamand University, Beirut, Lebanon


E. Azar, None

G. Juvelekian, None

F. Ghandour, None

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