Best Cases from the AFIP Fatal 2009 Influenza A (H1N1) Infection, Complicated by Acute Respiratory Distress Syndrome and Pulmonary Interstitial Emphysema

In July 2009, a 56-year-old man with a history of asthma presented to his primary care physician after 3 days of nonproductive cough, fever, and dyspnea. The patient was treated with clarithromycin and pulse-dose prednisone for presumed community-acquired pneumonia and asthma exacerbation. He returned to the clinic 6 days later with worsening symptoms and speaking in one-to two-word phrases. The patient was admitted to the hospital, and 1 day later, he was transferred to the intensive care unit because of declining respiratory status. Although initial direct fluorescent antibody (DFA) tests for influenza A+B, respiratory syncytial virus, adenovirus, parainfluenza, and metapneumo viruses were negative, the patient was empirically treated with oseltamivir and broad-spectrum antibiotics. However, his oxygen requirements continued to increase; intubation was performed and mechanical ventilation was begun on hospital day 4. Shortly thereafter, bilateral pneumothoraces and subcutaneous emphysema developed. Multiple pleural drains were placed bilaterally in the ensuing days. Persistent air leak from the right-sided chest tubes was noted. On hospital day 6, computed tomography (CT) of the chest was performed. Results from real-time reverse-transcriptase polymerase chain reaction (RTPCR) assay of specimens obtained from bronchoalveolar lavage were positive for 2009 influenza A (H1N1) RNA. Because of increasing difficulties with ventilation, CT pulmonary angiography was performed on hospital day 9; the results were negative for embolism. The patient continued to decompensate, eventually requiring multiple vasopressor agents, 100% FIO2, and inhaled nitric oxide. Hypoxemia worsened, and on hospital day 16, the patient became profoundly bradycardic and then asystolic. Postmortem examination was conducted shortly thereafter, with the consent of family members.