Severe adenovirus community-acquired pneumonia in immunocompetent adults: Chest radiographic and CT findings

Background: Severe adenovirus pneumonia and its associated imaging features are well-described in immunocompromised patients but are rare and poorly understood in immunocompetent adults. We sought to describe the radiographic and CT findings of severe adenovirus community-acquired pneumonia (CAP) in eight immunocompetent adults. Methods: We reviewed systematically chest imaging manifestations of laboratory-confirmed severe adenovirus pneumonia in eight immunocompetent adults from April 2012 to April 2014. Results: All patients showed abnormal results on initial chest radiograph and CT, with the exception of one normal initial chest radiograph. The abnormalities of the initial chest radiographs were unilateral (n=4) or bilateral (n=3), including consolidation (n=4), dense patchy opacity (n=3), ground glass opacity (GGO) (n=1), and pleural effusion (n=1). The initial CT findings consisted of unilateral (n=5) and bilateral (n=3) abnormalities, including consolidation (n=8), GGO (n=2), pleural effusion (n=3) and small nodules (n=1). Focal consolidation was the predominant finding in six patients whose initial CT scans were examined within one week after illness onset. Follow-up radiologic findings showed rapid development of bilateral consolidation within ten days after illness onset, usually accompanied by adjacent ground-glass opacity and pleural effusion. The parenchymal abnormalities began to absorb around two weeks after illness onset, with no appearances of fibrosis. Conclusions: Severe adenovirus CAP in immunocompetent adults mainly appears as focal consolidation followed by rapid progression to bilateral consolidation, usually accompanied by adjacent GGO and pleural effusion, which may resemble bacterial pneumonia. Adenovirus should be considered in severe pneumonia cases with negative cultures and failure to respond to antibiotics.