COVID-19 or not?

Bilateral multilobar ground-glass opacities are characteristic features of COVID-19 pneumonia. However, the dif-ferential diagnosis of ground-glass opacities is challenging. The aim of this paper was to share our experiences with other colleagues. The first patient presented with anosmia and loss of taste. Legionella antigen in urine was positive. The second patient had bilateral ground-glass opacities, which predominantly involved the upper lung zones and lym-phopenia. Radiological findings were the same with the radiological control of 8 months ago, and she had a diagnosis of sarcoidosis. The third patient complained of dyspnoea. The inspection of national health system records showed a histological diagnosis of nonspecific interstitial/organizing pneumonia. The fourth patient had findings suggestive of congestive heart failure such as bilateral pleural effusion, peribronchial cuffing, and interlobular septa thickening. The co-existence of multiple ill-defined centrilobular ground-glass opacities suggested a concomitant disease but lesions disappeared with furosemid infusion within 5 days. The fifth patient presented with only right upper lobe consolida-tion. The opacities did not exceed the horizontal fissure. The intact fissure suggested a bacterial aetiology, but PCR tests of the nasopharyngeal samples were positive for COVID-19. This finding suggested that pulmonary infiltrate of COVID-19 was inflammatory rather than infective in nature. In conclusion, old imaging studies were more useful in the differential diagnosis.