The authors report the case of a 21-year-old female patient with a six-month history of progressive dyspnea, dry cough, and weight loss. High-resolution computed tomography revealed a "crazy-paving" pattern with areas of focal sparing. The patient underwent transbronchial lung biopsy which confirmed the diagnosis of alveolar proteinosis. Two years later, without treatment, a marked improvement in pulmonary opacities was observed.

Keywords: Alveolar proteinosis.

The present study aimed to review high resolution computed tomography findings in patients with H1N1 influenza A infection. The most common tomographic findings include ground-glass opacities, areas of consolidation or a combination of both patterns. Some patients may also present bronchial wall thickening, airspace nodules, crazy-paving pattern, perilobular opacity, air trapping and findings related to organizing pneumonia. These abnormalities are frequently bilateral, with subpleural distribution. Despite their nonspecificity, it is important to recognize the main tomographic findings in patients affected by H1N1 virus in order to include this possibility in the differential diagnosis, characterize complications and contribute in the follow-up, particularly in cases of severe disease.

Keywords: Influenza A (H1N1); Pulmonary infection; Pulmonary viruses; Computed tomography.