Delay of COVID-19 diagnosis due to aspiration pneumonia.

COVID-19 was first confirmed in December 2019 in Wuhan, China and is now spreading worldwide. Diagnosis of COVID-19 is sometimes difficult due to the absence of symptoms and its tendency to be masked by other diseases. In this paper, we report a COVID-19 case in which diagnosis was delayed due to aspiration pneumonia. A 64-year-old man visited our department for evaluation of swallowing function. However, during the examination, the patient aspirated testing food and subsequently developed a fever. Based on his medical history and computed tomography (CT) images, he was diagnosed with aspiration pneumonia and admitted to the hospital to begin treatment. However, after admission, his respiratory condition deteriorated, and the result of a COVID-19 polymerase chain reaction (PCR) test was positive. Previous reports have shown that CT images in cases of COVID-19 pneumonia were normal in the early phase, and abnormalities usually appeared approximately 6-11 days after onset. Common findings of COVID-19 are consolidation, ground-glass opacities, and a distribution of lesions predominantly in the bilateral inferior lung field periphery. It is difficult to differentiate COVID-19 pneumonia from other types of pneumonia; it should therefore be listed as a differential diagnosis during the current pandemic.