[Does SARS-CoV-2 cause lung inflammation even in mild clinical courses? : A multicenter report from outpatient care].

In spring 2020 imaging findings of the lungs were found in several radiological practices and in outpatient clinic patients, which indicated acute or previous viral pneumonia. It was striking that many of the patients affected had only mild symptoms. In this case study it was investigated to what extent SARS-CoV‑2 can cause lung involvement even with minor symptoms. In this study five outpatient radiological centers and two inpatient hospitals in North Rhine-Westphalia and Baden-Württemberg in Germany were involved. The retrospective analysis included outpatients with radiologically detected viral pneumonia, who were examined in March or April 2020. The clinical symptoms were divided into severity levels 1-5 using a simplified clinical score. The lung images were evaluated with respect to features specific for COVID-19 . The presence of a SARS-CoV‑2 infection was verified using PCR, antibody testing and/or typical computed tomography (CT) morphology. A total of 50 patients were included, all of whom had radiological signs of viral pneumonia. The majority had no or only few non-specific symptoms (26/50). This was followed by mild symptoms of a flu-like infection (17/50). Severe forms were rare in outpatients (7/50). Detection of COVID-19 was successful in 30/50 cases using PCR and in 4/50 cases using an antibody test. In 16/50 cases the diagnosis was based on typical CT criteria and on the typical COVID patient history. A SARS-CoV‑2 infection leads to lung involvement more often than previously assumed, namely not only in severely ill hospitalized patients but also in cases with only mild or even non-specific symptoms.