Addressing pulmonary fibrosis as a sequel in critically ill COVID-19 patients

INTRODUCTION: The SARS-CoV-2, first observed in China and responsible for COVID-19 disease, has triggered a serious global health crisis. There is evidence that this virus interacts with the angiotensin-converting enzyme 2 (ACE-2) with tropism for lungs, heart, kidneys and intestine cells. An intense respiratory viral attack was observed, causing serious lung damage such as respiratory failure. AIM: To highlight pulmonary fibrosis as the main sequel in recovered patients. MATERIAL AND METHODS: As a systematic review, Latin American Literature in Science Health (LILACS) and Virtual Health Library (VHL) databases were consulted for open access articles released between 2015 and 2020. As search guide: "Inflammation", "Fibrosis", "Lung" and "SARS-CoV-2" were used as descriptors. Among 16 articles found, 7 fulfilled the aim of this research. Fully available articles in Portuguese or English were used as inclusion criteria. RESULTS: Patients with Covid-19 have shown fever, dry cough, dyspnea and fatigue as mainly symptoms. The vast majority shows a favorably evolve, however, about 20% develop to a severe form of this disease, including acute respiratory distress syndrome (ARDS). Lung biopsy samples evaluations carried out by medical doctors in Italy revealed evident pneumocytes desquamation and hyaline membrane formation in the right lung, indicating ARDS, there was also pulmonary edema and hyaline membrane formations in the left lung, highly suggesting of an early stage ARDS. Severely emphysematous areas with diffuse alveolar damage and fibrotic exudate were identified in critically ill patients through necropsies, highlighting the occurrence of pulmonary fibrosis upon them. A European study group noted that patients with COVID-19 hospitalized in the ICU for a long period may progress with sequelae, just as long-term mechanical ventilation can generate pulmonary fibrosis. CONCLUSIONS: Pulmonary fibrosis has been described as one of the main sequelae of Covid-19, triggering chronic respiratory failure. However, more researches and studies in recovered covid-19 patients are still necessary to prove this association.