In COVID-19 related end stage lung disease, there are two distinct phenotypes. The first phenotype is the COVID-19 related acute respiratory distress syndrome (CARDS) showing a classical histopathological pattern of fibrotic diffuse alveolar damage (DAD). The second phenotype is the post-COVID pulmonary fibrosis (PCPF), in which the diagnosis is based on the combined clinical, radiological and (if available) pathological information. Both phenotypes have different clinical features, risk factors, biomarkers and pathophysiology. The exact prognosis in these two phenotypes as well as optimal treatment needs further studies.Key messagesTwo different phenotypes exist for COVID-19 related pulmonary fibrosis. The CARDS phenotype has a worse prognosis compared to the PCPF phenotype, which requires longer-term follow-up and evolves without ARDS picture. The best treatment options for the two different phenotypes, such as anti-fibrotic drugs or lung transplantation, still needs to be defined in future studies.
Keywords: Pulmonary fibrosis; hypothesis; lung transplantation; prognosis.