[Follow-up of patients after COVID-19 pneumonia. Pulmonary sequelae]

Coronavirus disease 2019 (COVID-19) is an infection caused by SARS-CoV-2 that has caused an unprecedented pandemic with a high rate of morbidity and mortality worldwide. Although most cases are mild, there are a considerable number of patients who develop pneumonia or even acute respiratory distress syndrome (ARDS). After having recovered from the initial disease, many patients continue with various symptoms (fatigue, dry cough, fever, dyspnea, anosmia, and chest pain, among others.), which has led to consider the possible existence of "post-COVID-19 syndrome". Although the definition and validity of this syndrome are not clear yet, several studies report that individuals who have recovered from COVID-19 may have persistent symptoms, radiological abnormalities, and compromised respiratory function. Current evidence suggests that there is a large number of pulmonary sequelae after COVID-19 pneumonia (interstitial thickening, ground glass opacities, crazy paving pattern, and bronchiectasis, among others.). Likewise, it seems that pulmonary function tests (spirometry, DLCO, 6MWT, and measurement of maximum respiratory pressures), in addition to high-resolution computed axial tomographies (CAT scan), are useful for the assessment of these post-COVID-19 pulmonary sequelae. This review aims to describe the possible pulmonary sequelae after COVID-19 pneumonia, as well as to suggest diagnostic procedures for their correct assessment and follow-up; thus, allowing proper management by a multidisciplinary medical team.